IFATCA The Controller - 4th quarter 1998

THECONTROLLERS JOURNAL

Free Flight Special

OF

Greek ACC

AlR

TRAFFlC

CONTROL

Chile Registration Form

Christmas Special

4/ 98 4th quart er 1998 volume 37 ISSN 0010 - 80 / 1

PUBLISHER IFATCA , Internat ional Federat ion of A ir Traffic Con tro llers' A ssociations. See bo tt om of page 4 fo r contact add ress.

THE JOURNAL

EXECUTIVE BOARD OF IFATCA Samuel Lampkin President and Ch ief Executi ve Offic er

Paul Robinson Dep uty President

NTROLLER OF

Al-R

T R A F F IC

CO N TRO L

ln This lssue

Oliver Farirayi Executi v e Vice-President Afr ica/

5

M iddl e East

Foreword

Free Flight - The Executi ve Vice President Professional's v iew point

George Chao Pao Shu Exe cut iv e Vice- President As ia/ Pacific

Marc Baumgartner

6

Exe cuti ve Vice -President Europ e

Foreword

Free Flight - The Exec ut ive Vi ce President Technical 's view point

John Redmond Execu tiv e V ice-President Finance

Martyn Cooper

8

Executive V ice-Presid ent Professional

Free Flight

Automation tools for Controllers

Martin Cole Execut ive V ice-President Techn ical

Terry Crowhurst

16

Executive Board Secretary/ Edi tor

Free Flight

One Controller 's perspective

EDITOR Terry Cro w hur st

20

29 Heritage Law n, Langshott ,

Free Flight

A pilot' s viewpoint

Horl ey, Surr ey, RH6 9XH, Un ited Kingdom .

Tel +44 (0) 1293 784040 Fax. +44 (0) 1293 771944

26

Free Flight

A summary by Anthon y Smoker

emai l: te rry _crowh urst @compu serve .corn (home) Internet : terry.crowhurst @srg .caa.co .uk (w or k)

28

A Christmas

story

Philippe Domagala reports from Greece CMG CHAIRMAN AND ACCOUNTS Edge Green O .B.E 4 The Rookery

30

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Decemb er 1998

32

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CONTROLLER

IssuesAppear End of March, June, September, December Contributors Are ExpressingTheir Persona l Pointsof View and Oprn1ons_ Which May Not Necessarrh, CoincideWith Thoseof The International Federation of AorTrafficControllers· Associations . IFATCA IFATCADoes Not AssumeRcspons1bil1t y For Statements Made and OpinionsExpressed, 11AcceptsRespons1b1l1ty For Publ1sh111g TheseContributions ContributionsAre WelcomeasAre Commentsand Cnt1c1smNo Payment Car be Made For Manuscripts Submitted For Publ1cat1o n 1nThe Controller The Editor Reserves The Right to Make Any EditorialChanges 1nManusrnpts. Wn1Chm· BelievesWill Improve The Matenal Withou1 Altermg The Intended Meaning Wntten Perm1ss ron by The Editor 15NecessaryFor Repr1ntmgAny Part of This Journal

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CONTROLLER

Editorial Free

Flight Terry Crow hurst, Edito r

THECONTROLLER n the three years since the RTCA Select committee

contro llers of some of t he issues,

pub lished its report,

directons that the Free flig ht

introduced the concept of Free Flight , there has been a fre nzy of activity. Many have looked at the

questions and some of the concept has generated . It is hoped that this edition of The

concept, thought about it , and

Contro ller will provide IFATCA members some idea of the

come to their ow n conc lusio ns

current state of play, and

as to what it all means. This

stimulate debate. If you have any

leaves us today w ith the situation

questions or comm ent , please

that when someone asks a

write to me and share your views

quest ion about Free Flight, the

or thoughts on the topic. To lead

answ er all too often repre sents

in to the topic , bot h the

an interpretation that is but one

Executi ve Vice Presient

of many.

Technical and Professional have w ritten Forew ord s respective ly,

The follo w ing articles in t his

to addressth e technical and

edition provide an introduction to

human factors aspectsgenerated.

THECONTROLLER REGlONAL SUB-EDlTORS AFRICA MIDDLE EAST

ASIA PACIFIC

Mr Albert Aidoo Taylor

Accra

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Hong Kong Tel: +852 25510081 Fax: +852 23628101

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Fax:+233 21 773293

AMERI CAS Rosanna Baru

EUROPE

(ATCA U)

Mr Philipp e Domagala

P.O . Box 6554 Monte v ide o

M erelstraat 5 NL - 6176 EZ Spaub eek

URUGUA Y

THE NETHERLAN DS

Tel: +598 2770299

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· I 11 CONTROLLER

5

Free Flight

Foreword

The Professional Viewpoint

•

Martyn Cooper, IFATCA Executive Vice President Professional

As I considered the central theme for this issue of The Controller, I w as struck by the relationship that air traffic Cont rol has had with the development of civil aviation and the f act that thin gs have almost turned full circle. n the early days of flying, pilots had everyth ing mostly their own way They generally only flew w hen the weather was good and then only during the day.

Navigation was based on road maps and followin g railway lines. If they got lost. it was easy enough to land and ask the way. It was, wh en the use of the aeroplane became viable for public transportation, that the need for someone on the ground to monitor what was going on became important Using light signals and then radio , communication between pilots and ground per sonne l developed . As airf ields became airports, control became ever necessary to assist with the safe departure and landing of aircraft. Flight planning, regu lar weather reporting and alerting serv ices came into being W ith the control tower came t he 'contro ller' and the f irst v isible signs that the freedom in t he air was passing from pilot to ground staff.

The aftermath of t he Second World War found the wo rld a much smaller place, w ith larger aircraft available to trave l great distances with accuracy. The radio aids wh ich had assisted the bomber finding the target. now enabled route structures to be developed and de livered passengers to their

I

6

destinations safely and without or wit h the airspace that too much concern for weat her enables continually increasing conditions. air traffic to be handled safely.

Th e routes became We have seen in Afr ica, and "corridors in the sky" and the other parts of the wor ld, th at need for control led flight to investment in ATC systems - to avoid airborne collisions provide the service that became centra l to the task of controll ers want to give and the air traffic controller. t he airlines expect - is simply Freedo m fo r the pilot became not happening . extreme ly limited, w ith a list of Pilots, and airlines, and rules and procedures contro llers, are all victims of established to support virtua lly t he same system th at has failed the wh ole length of a to keep up w ith the time s. commercial flight. ATC w as in Wherea s, we have allowed 'charge' and held the reins of ourselves to advance in commercial civil aviation from airborne techno logy - the takeoff to landing. It all gro und-based systems have seemed to be going so we ll been allowe d to stagnate. for the controller.

Ever increasing demands to fill But th e airlines faced delays up th ose air corridors, w ith at peak times . Commercia l aircraft going ever faster, has needs demanded more put a considerable strain on eff icient use of expensive the provision of a safe ATC aircraft and meet compet it ive service. TCAS, perhaps fir st t ime schedu les. It was considered absolutely patently clear t hat ATC wasn't necessary as a 'last resort delivering the service to meet collision avoidance system' for increasing de mands . some parts of the wor ld, is In simple te rms, t he now mandatory for all stages development of ATC system s of the fl ight in many countries . has not matched aircraft Pilots face t he frustration of systems and ATC oft en falls know ing exactly w here t hey short of what airlines and pilots are, whe n it is patent ly obvious now expect. But, is th is the the controller doesn't It is, controllers¡ fau lt 7 After all, the therefore, not surprising t hat airl ines 'pay' for the service pilots want t he freedom of the they rece ive and it is air, again. A irlin es and pilots reasonab le for the m to expect want to break free from the the ATC system to de liver. constraints of t hose narrow air The truth is, t hough, that many corridors that for ce aircraft contro ller s are not work ing togethe r and then require with the equ ipm ent t hey need, overloaded contro llers to

separate them. Th ey wa nt to use the expens ive technolog y that comes standard with the aircraft . The y want to avoid the delays caused by ATC systems that simply cannot cope w ith the traffic. The y want the freedom to fly. In short, the y want the "Free Flight" concept.

But, and it is another 'but', th e concept of "Free Flight " remains withi n the spectrum of contro lled airspace - and with it. the need for gro und based monitoring and 'control' .

Where then, does th is place th e contro ller?

Pilot s have already ind icated that they do not want to see the job of th e contro ller tran sferr ed directl y int o the fli ght deck. Th ere are good reasons for th is, because despite t he advanced t echnolog y that modern aircraft use, t here become s an increasing need fo r the pilots to wo rk hard at being pilot s ensurin g that th ey are full y aware of what the aircraft is doi ng. Automated systems now und ertake so many of the respons ibilities previously allocated to the pilot s, that far from the systems monitoring the human acti ons, it is ve ry much th e other way round .

Taking on the add itiona l responsibility for separat ion is not something the pilots have time for, w hen prep aring t hemselves for take off or landing, or operating in the comp lex Termina l Contro l Areas .

Unl ess the contr oller is provided w ith equipme nt at least as good as the pilot has, t hen the "Free Flight" concept wi ll be grounded . In order for the cont roller to be an active

CONTROLLER

participant in the "Free Flight" concept, advanced conflict detection and resolution systems wi ll have t o be adapted for ground based use.

What use w ill it be, for a pilot to know what is going on and the controller a mere observer?

Is that how the circle w ill be closed, w ith the controller out of the information loop, yet still to be held responsib le for controlling the "Free Flight" environment?

The lack of Air Traffic Management to provide efficient and economic air traffic services is clearly leading airlines to pursue their ow n ideas for the future.

Whether it is TIBA, TCAS or "Free Flight", the important and essential relation ship between aircrew and air traffic controllers is being undermined . Th e pilots want to fly and the co ntroll ers wa nt to control - but in a way that not only affords safety, but also exp resses an acknow ledgeme nt of the basic right for freedom to fly in the air. For too long that freedom has been blocked by lack of grou nd-b ased technology and the resistance to change exist ing procedures and rules .

The "Free Flight" concept now enab les us to review the who le futur e of A ir Traffic Management and consider the changes that pilots and airlines desire and which contro llers can pro vide, if only t hey can share in the tec hnology, too .

The te rm "Free Flight" has been central to the minds of humans, ever since thought s of leaving the ground became a reality with the Wright brothers If w e have come fu ll circ le, then those early steps for freedom into the air is not Just a hum an aspiration - it is now a basic commerc ial requirement.

I'

ii CONT ROLLER

Free Flight, an idea whose time has come - and gone?

The Technical Viewpoint Martin Cole, IFATCA Execut ive Vice President Technica l

At a recentIFATCAmeetingin Montreal,one of the participants madea statementthat left me a littlestartled.

The statementwas,"Perhapsit'stimeto considerthat Free Flightshouldnot be the ultimategoalof CNS/ATM". was surprised because this ran directly counter to all I have heard on this topic for the last three or more years.

There has been the unquestioned assumption that the natural evolution of all our current and planned improvements in the air traffic system was leading up to the "eventual" implementation of the full concept of Free Flight. I wi ll leave the details of this full, or mature, concept of Free Flight to the authors of the excellent articles contained in thi s issue.

No one can argue that the current state of the global air traffic contro l system is adequate to meet even today's level of aircraft traffic, much less the projected doubling of system demand in the coming years.

This inadequacy is tr ue in both the industrialised nations as wel l as in the develop ing countries of th e world . There is an urgent need for technologica l improvements that w ill allow control lers to wo rk more aircraft wit h even high er levels of safety than in th e current ATC system Some of

I

these new technologies include conflict detection and resolution tools, datalink and improved vo ice communications capabilitie s, enhanced surveillance systems, and an automation of the basic "housekeep ing" duties of the control ler (e.g . strip and fligh t plan management and ground inter-ATSU co-ordination).

Somehow the "experts" have made a leap from thi s real need for technologica l improvement to the requirement that we must remove the controller (as the supposed "limiting factor") from t he ATC equation. This is a leap about w hich I am no longer completel y conv inced. As I become more acquainted with th e levels of integrit y and reliability to w hich new systems are being planned or built, coup led w ith expanding research into the problems wh ich highly automated systems cause for maintaining skill levels of the human operators, I see a disturbing picture begin to emerge . The spectre that

reducing separat ion standards and/ or increasing airspace capacit y will require even faster human response t imes w hen "i ntervening " in the system, at a time when syste m automation leaves t hose same humans with atrophied skills, demands t hat w e qu estion some of the previousl y untouchable assumptions of Free Flight.

This questioning of assumptions does not mean t hat we, as controller s, can afford to ignore or repudiate the prog ress and research in impro ving how we accompli sh our roles in the ATC system . We mu st participate ful ly at local , national and inte rnational leve ls in the deve lopment of the CNS/ ATM concept , which may include elements of Free Flight that can be integrated into , rather t han replace , a ground -oriented ATC system. But we must also be w illing to question any "goal" (even one as popular as Free Flight) that would lead to an ATC system that is less, rather than more , safe than it 1stoday

7

Free Flight Automation Tools for Controllers •1n Future Air Traffic Control RajaParasuraman, JacquelineDuley,& AnthonySmoker Cogniti ve Science Laboratory , The Catholic University of America , Washington DC, USA As the 21st century draws near, commercial air travel can look back on al most 100 years of service w ith some satisfact ion fo r its excellent safety record. How ever, the volume of air traff ic is likely to doub le over the next two decades, posing a threat to the capacity of the air traffic control (ATC) system [l 2] M oreover, even if the accide nt rate remains at its current low value , in the near future one major commercial airline accident w ill occur every w eek in some part of the world [3] .

The recent call for a five-fold improvement in safety by the Gore Commission in the U S [4] was clearly mot ivated by th e need to avoid t he publ ic outc ry t hat w ould result from such an outcome.

To meet this challenge, the ATC system must change in fu ndamental w ays. Several proposals have been put forw ard. In the U.S there has been much interest in Free Flight (FF), w hich w ould allow user-p referred rout ing and fr ee manouvering, among ot her changes aimed at minimizing ATC restr ictions [5] A n alternative is to extend the current system of groundbased ATC, but to use autom ation to support air t raffic contro llers in the management of an increasingly dense airspace [6] European proposals have similarly ranged fro m aircraft self-separat ion [7, 8] to ground -based cont rol w ith enhanced systems for communic ati ons, nav igation , and surveillance [2] Irrespectiv e of w hich proposal is imp lemente d , the increasing compl exity of f uture airspace w ill requi re the development of automat ion

8

tools to support air traffic controllers. Controllers are likely to continue to be respons ible for airspace management and safety, although there wi ll probably be greater "cooperative" decisio n making between control lers and pilot s in airspace regimes w here traffic densities allow this [9].

Automation too ls w ill be needed for planning, traffic management, conflict detection and resolut ion, etc.

Th ese systems must be designed w ith serious atte nti on to controller human facto rs if the y are to be successfully fie lded [6, 10, 11] In th is article, we consider two major hum an factors issues critic al t o the design of ATC automat ion tool s. In particular, we show how to: • Design automat ion tools for effect ive use by contro llers by implementing appropriate types and levels of automatio n. • Develop approp riate interfaces for future ATC systems by incorporating controller informat ion requireme nts into design.

Automation in ATC Let us beg in by defining w hat w e mean by automation, because the term has been used in a number of different w ays. Automat ion does not refe r simp ly to computer ization or modern ization . For example , updat ing an aging co mputer wi th a more pow erf ul system w ou ld not necessarily const itu te auto mat ion , no r wou ld repl acing a low-r esolution, monoc hrom e displa y w ith a 2K x 21<co lor d isplay. Rat her, we

HIGH10. The computerdecides everything, acts autonomously, ignoring the human.

9. informs the human only if it, the computer, decides to 8. informs the human only if asked, or 7. executesautomatically,then necessarily informs the human, and 6. allows the human a restricted time to veto before automatic execution, or 5. executes that suggestionif the human approves, or 4. suggests one alternative 3. narrows the selection down to a few, or 2. The computer offers a complete set of decision/act ion alternatives, or LOW 1. The computeroffers no assistance: human must take all decisions and actions.

Table 1. Levels of automation of decision and action selection

use th e fo llowing definition (12] : "Autom ation refers to a device or system that accomplishes (partially or fully) a function that was previously carried out (partially or fully) by a human operator."

According to this definition, an early form of ATC automation was the presentation on the primary visual display (PVD) of electronic data blocks, w hich automated the aircraft identif ication function previously carried out by controllers in communication w ith pilots . Another example (in Europe) is the use of On Line Data Interchange between ACC's , w here the task of passing an estimate by telephone is replaced by automatic data transfer. A current example of ATC automation involving a more complex function is the converging runway display aid (CRDA) , wh ich elimin ates the need for t he contro ller to mentally project the approach path of one aircraft onto that of another landing on a convergi ng runway so as to maintain a 2 nm separation [13 ] Finally, an example of an automation system currently undergoing field tria ls is the Center Tracon Automation

System (CTAS). One component of this system, the Descent Adv isor, will replace the controller's need for determining the best top-ofdescent point for an aircraft entering a terminal area by optimizing the descent trajector y for that aircraft and the planned arrival sequence at the terminal [14] .

A Human-Centered Model for Types and Levels of Automation In ou r definition, automation refers to the replacement, either full y or only partially, of a function previously carried out by th e controller . Thi s impl ies that automation is not all or none, but can vary across a continuum of leve ls, from t he lowest leve l of fully manual perfor mance to the high est level of full automation Several levels between these two extremes have been proposed [6 15] Table 1 shows a 10-po int scale for auto mation, with higher leve ls represent ing incr eased autonomy of comp uter over human action [6] . For example , at level 4 , the computer suggests one decision alternat ive, but the human retains authority for executing that alternat ive or choosing another one However , at a higher level 6, the system gives t he hum an only a limited

Ii CONTROLLER

"New ideas

ost likelv

rom ex eritnced mind s

,, Egil A lv ier

Senior Projec t M anage r GA RE)(

Creativity is all abo ut solving a problem in a new and bette r wa y, and obviously one needs to see a problem from all ang les t o produce bette r so lu t io n s for the futu r e. Th is k ind o f insight can only be gai ned from lots of expe ri e n ce , according to sc ie nt ifi c studies of crea ti v ity .

Navia Aviatio n' s GA REX voice communicatio n co ntr o l systems have bee n install ed at leading air po rt s aro und the wo r ld fo r m o r e than 30 years , continuo usly carrying new develop m ent s. Th e re · s no need fo r a r evo luti o n when yo u, ve go t it ri ght in t he fir st plac e . But t he r e ' s alw ay s r oo m for im pro vem ent - m o st likely cr eated by so m eo ne with a lo t o f exp e ri e nce in t hat pa rti c ular fi e ld . You kno w w her e t o look for expe ri ence, do n't yo u?

NAVIA AVKA li

N

A COM PANY I N THF NAV I A GRUll

Normare

CONTROLLER

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9

Free Flight Information Acquistion and lntergration

Decisionand Action Selection

Action Implementation

InformationAcquistion and lntergration

Decisionand Action Selection

Action Implementation

Automation Level

AutomationLevel

AutomationLevel

AutomationLevel

AutomationLevel

AutomationLevel

High

High

High

]

]

Low

Fig 1. Levels of automation

Low

for-three

• Information gather ing (or acquisition) and inte grat ion • Decision and action selection.

• Act ion imp lementat ion Automat ion of informat ion acquisition app lies to several indepe ndent operat ions

Lo w

independent

tim e for a veto before carrying out the decision choice .

Automation systems operate at specific levels w it hin this continuum. For example, a confl ict detection and resoluti on system that notifies a controller of a conflict and suggests a resolution wo uld qualify as level 4 automat ion.

Under level 6 or higher, the system w ould automatical ly execut e its ow n resolution advisory.

Aut omation can also be decomposed by funct ional dimensions, thus def ining differe nt typ es of automation (see Figure 1 ) The scale in Table 1 applies mainly to automation of decision and action selection, or "output" fun ct ions, such as the form ulat ion of a clearance .

However, automation may also be applied to "input" f unctions, i.e , informat ion gather ing (or informat ion acquisition) and integrat ion For examp le, the data block represe nts information auto mation rather t han dec ision/ action automation . Thi s type of automat ion supports but doe s not remove the controll er from the decision-making and action implementat ion loop We propose th at autom ation can be app lied to t hree broad classes of fu nctions:

10

] functions

performed on input data.

These include operations of filtering, in which certain items of informat ion are selected for control ler attention (e.g., highlighting the data block of a particular aircraft), and integration, in w hich several input variables are combined into a single value (e.g., pro viding time to loss of separation based on position, heading, and speed of a pair of aircraft). Automation of decision and action selection can vary in leve l according to the degree of autonomy given to t he computer, as described previously. Finally, the action implementation scale refers to the actual execution of the action choice (e.g., "p ressing the button"). Often this scale w ill have only two levels, manual and automatic, as opposed to the continuum of levels in the other scales.

The three functional dimensi ons correspond roughly to th ree stages of human info rmation processing Automation in each dimension can vary across several leve ls, from low to high . A completed system can invo lve automation of all three dimensions at d ifferent levels.

Thu s, for examp le, a given syste m (A) could be designed to have moderate to high information aut omation, low de cision automation , and low act ion automation. Another syste m (B), on the other hand , might have high levels of automat io n across all three d imensions (see Figure 2)

,tr=======igh System B Sys tem A

1

10Hfigh

101

-

--

,-_l_ (___ --------:;-

Lo w

Fig 2. Systems with different

I

High

J Low

Lo w

levels of automation

Human Performance in Automated Systems Before applying this model of automation to ATC, we briefly describe research on human-automation interaction .

This research, based on experiments, simulations, and field studies, has found that automation can have both beneficial and negative effects on human performance [12] .

There is not the space here to consider all the effects that have been uncovered. We wil l briefly discuss four effects: mental work load, situation awareness, complacency, and skill loss.

With respect to mental workload, the evidence suggests that well-designed automation can reduce work load, thus allowing the contro ller to focus on other tasks or to handle a greater number of aircraft efficient ly.

Automated handoffs and the use of conflict probe tools (such as Maastricht UAC's "VERA" tool) are two such examples. Note, however, that instances of automation "increasing" work load have also been found [12 .16].

Against these benefits, several human performance costs of automation have also been noted. First, automation of decision-making functions may reduce the control ler's situation assessment or "picture" of the airspace [17] Second , high- level automation may lead to comp lacency, in w hich control lers may not detect occasional failures in the automation itself or in the

across dimensions

processes that it controls [18].

Third, if the dec ision-making function is consistently selected by automation, there will come a time when the controller wi ll not be as skilled in performing the function manually. These costs collectively demonstrate the disadvantage of taking controllers "out of the loop, " particularly for decisionmaking functions [6. 12] A ll three of these sources of vu lnerabi lity may pose a critical threat to safety in the event of system failure . Automation must therefore be designed to ensure that such potential human performance costs do not occur. We apply our model of types and levels of automation to show how th is may be achieved.

Designing for Effective Use of Automation by Controllers The major criteria for applying automation in many complex systems tend to be technological feasibility and cost. These can be valid reasons for automation if there is no detrimental impact on human (and hence, system) performance in the resulting system. Howeve r, as discussed previously, this may not be the case w ith certain "clumsy automation designs.

Consequently, human performance issues must be considered 1ndesigning automated systems What is the app ropr iate type and level of automation that should be app lied to ATC? There is no simple answer to

, , CONTROLLER

this question: but the threedimensional model we have proposed can provide a guiding framework. The model is neither a static formula nor a prescription, because several other factors also need to be taken into account. Two important factors are automation reliability and risk. Both need to be considered in evaluating choices of the appropriate level of automation.

Automation reliability is an important determinant of human use of automated systems because of its influence on trust. Automated systems may be under-utilized or disabled because of mistrust, as in the case of alarm systems that frequently give false alerts [12]. On the other hand, excessive trust can lead to complacency. The controller must clearly adopt the correct middle ground between these extremes. Whenever a new

automated aid is introduced into the ATC system, training is needed to ensure that controllers can assessthe conditions under which the aid is likely to be correct [19]. If the controller is busy and such cond~onsoccu~then following the aid's directives is appropriate, given that the aid's reliability under those conditions has been certified.

But the controller must also be trained to be aware of the conditions under which the aid may be imperfect.

Reduced traffic awareness, complacency, or manual skill degradation may occur only for high-level decision/action automation. Information automation that selects and integrates data for the controller to support his or her decision making should be less susceptible to these human performance costs, because the controller remains "in the

Information Acquistion and lntergration

Decision and Action Selection

Automation Level High 10---

Automation Level High ---10

for reliable automation 1

-~

for reliable

automat12n

for high-risk functio~ ~ 1

Low

Low

Action Implementation Automation Level High 10 --oflow-l~el decision automation 1

-'-

Low

Figure 3. Influence of automation reliability and risk on recommended levels of automation.

loop." Our model therefore recommends that high levels of automation can and should be pursued for information acquisition, integration, and presentation for aiding controller decision making, so

long as the automated functions have high reliability.

Figure 3 illustrates this recommendation.

Assessing the appropriate level of automation for decision automation requires additional consideration of risk. For decisions involving relatively little risk, e.g., the

decision to handoff control of an aircraft to the adjacent sector, then the aforementioned out-of-theloop problems are unlikely to have much impact, even if there is a complete automation failure, because the appropriate defenses are in place. Because of the very nature of ATC, however, a large number of decisionmaking situations will involve some risk, e.g., issuing a climb clearance in a crossing conflict, where the separation is close to the minima. For

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Free Flight such situat ions, automation of decision and action selection should not proceed beyond a low t o moderate level, e.g., level 4, in w hich the computer suggests a decision choice, but th e controller is free t o accept or reject that advice (see Figure 3). System designer s w ishing to implem ent decision automat ion above t his level must show t hat the ir design will not lead t o problems of loss of sit uat ion aw areness, complacency, and skill loss.

This may be difficult to achieve fo r very high levels of decision automat ion .

(Adaptiv e automation , in which a fun ction is automated but then returned briefly and periodically to th e human operator. reduces comp lacenc y and can enhance situation awareness [20]. A recent study also found th at adaptive impl ementation of the CTAS automated system. in w hich confl ict resolution advisories were prov ided only under high traffic load. also reduced cont roller w ork load compared to wh en th ese w ere provided at all time s [21 ] .) Further work needs to be done to examine w het her adaptive automation would be fe asible in actual operations .

A system designer may object to the recom mendation that decision aut omat ion should not exceed a moderate level on t he grou nds th at if infor mat ion auto mation can be made high ly reliable , t hen decisi on automat ion can also be designed to be reli able .

Then w hy not implement high-level auto mation fo r thi s functi on too? Th e answe r is t hat althoug h decision-aidin g systems can be eng ineered to be high ly reliable fo r many know n cond it ions, t hey are not infallible The "noi siness" of the real wo rld , w ith variations d ue to w eat her, unexpected aircraft beh avior, system malfun ction s, et c., w ill mean t hat t here w ill alw ays be a set of cond it ions under which t he automat ion w ill reach an incorrect decis ion .

To allow the auto mation authority to execute that decision w itho ut contro ller input, especially under risky situations , may be foo lhard y.

Finally, if a low t o moderate level is implemented for

12

decision automation so that the controller remains in the decision-making loop and has final authority over the alternative chosen, then the actual execution of that choice can be automated if necessary, or performed manually if the controller so chooses .

These considerations can be summarized as follows (see also Figure 3). High levels of information automation can be pursued and implemented if the resulting systems can be shown to be reliable. For decision and action selection automation , how ever, high levels should be implemented only for low risk situations . For all other situations, the level of decision automation should note xceed t helevelofthe automation suggesting (but not executing) a preferred alternative to the controller .

Free Flight, Automation, and Controller Performance Free Flight w ill be supported by automated systems and technologies such as conflict probe, ADSB, datalink, etc. Therefor e, human-automation interaction is also relevant to an evaluation of FF Moreo ver, fr om the pe rspecti ve of t he controller, advanced FF and hig h-level decision autom ation both remo ve the co ntro ller from the decisionmaking loop concerning aircr aft separation, leading to the same poten t ially adverse co nsequenc es [6] .

Recent simulator studies have examin ed how FF may influ enc e controller perfor mance, situation awa ren ess, and w orklo ad .

One study co mpar ed a baseline co ndition correspo ndin g to current ATC proced ures w it h t hree FF co ndit ions dir ect rout ing w ith fl ight plan, d irect routing w ith deviat ions fro m fli g ht plan after sharing inte nt w it h t he

Tim e requir ed

Time

Tim e availabl e low

Level of deci sion autom ati on

high

Fig 4. Failure recovery time under low and high levels of decision automation

controller, and direct routing with deviations from flight plan without intent information [22]. Controllers reported significantly higher subjective workload when they were ignorant of the pilot's intention to deviate.

The mature stage of FF (referred to as the Holy Grail

by John Levesley in this issue of The Controller), will have been reached if technologies such as GPS, ADS-B and CDTI are integrated into a method of operation with ground based systems that affords aircraft operators considerable flexibility in the operation of their aircraft and a significant influence in the strategic and tactical control mechansims.

The result will be an airspace that is considerably more dense and comple x than it is today . Will the controller of the future still be able to monitor such a saturated airspace and intervene effectively if, for example, the pilots cannot resolve a conflict, bad weather encroaches into the FF airspace, or there is a system failure (e.g ., GPS)? To examine this issue, a recent study investigated how well cont rollers could detect conflict s and aircraft selfseparating events when all separation decision-making aut hority was removed from them, as it w ould be und er advanced FF [23] . Controlle rs missed up to 50% of the confl icts, especially und er high traffic. Self-separating eve nts

w ent unreported even more frequently (70-80%). When conflicts and self-separations "were" identified, they were reported at ver y short times prior to their occurrence.

These studies suggest that controller performance can be vulnerable under either high levels of decision automation or advanced FF,in which decisionmaking authorit y is ceded . The results suggest some caution in implementing high-level ATC decision automation. Given that FF may well lead to reduced aircraft separation , the very short notification times and low detection rate in the simulation study of advanced FF [23] raise some concern .

High-level decision automation and advanced FF will reduce the time available to recover from an emerg ency situation because of reduced separation and a den ser airspace . At the same time, the out-of-the-loop probl ems of complacen cy, reduced traffic aw areness, and skill loss will result in controllers requiring greater time to respond . Figure 4 shows this tradeoff between the time available and the time required to respond to an emergency [6] When the latter exceeds the former, failure recovery may be compromised We con clude t hat high -level decision automation and FF procedur es that result in controller s cedin g all decision making author ity can bot h have harmful eff ects Thi s doe s not mean t hat

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Free Flight automat ion should not be considered for future ATC systems. If reliable, high-level infor mation automation should be applied, t here is amp le evidence t o show that such automation can enhance controll er decision making .

However, th e kinds of inform ation most needed to support cont roller decis ion making are not yet full y understoo d . The w ay such information should be displayed t o controllers , namely th e int erfaces that should be used , also needs systematic investigation. We examine th ese issues next.

Controll er Information Requir ements for Future ATC Sy stems As describ ed previously, informati on automation includes softwa re interf ace operations such as highlight ing time-critical events, filt ering unnecessary or irrelevant data , and presenting data using infor mative form ats rather than reprodu cing raw dat a. Before discussing how such infor mation automatio n can be designed , let us consider w hat informat ion sources the contro ller has available .

The PVD provides the controller with several data sources, primarily aircraft identity and flight path parameters such as direction of flight, altitude, and in some cases grou ndspeed, as we ll as informat ion on the sector airspace-waypoints, airways, sector boundar ies, and areas of special use airspace. The contro ller can also obtain information regard ing current procedures and restrict ions from manuals and NOTAMS .

Procedures and regulations are also learned and committed to t he trained contro ller's memory .

Weather info 1¡mation is available, e g , from METAR and TAF reports Detailed 1nformat1on about an aircraft 's flight path and intentions 1s available to the contro ller via

14

the aircraft fl ight progress strip in either an electroni c or paper form or via electronic flight data. Finally, a controller's information needs may be met by querying pilots, supervisors, and contro llers in adjacent sectors. This information might include weather changes previously not forecasted, pilot requests, as w ell as emergencyrelated info rmation.

Note that in addition to these sources of information, some items that are required for the control of traffic may be available dynamically, such as estimated approach times or co-ordinated levels out of the sector etc. Information presentation is dynamic in the sense that it can be available alw ays or at all times , "at the discretion of the controller", or at the discretion of the soft w are/ computer system.

Information that is present at all times requires no physical manipulation or search by the co ntro ller, e.g . because th e aircraft call sign is always show n on the PVD, it is not necessary fo r the controller to perf orm a keystroke or search t hrou gh a manual, etc . in order to obt ain t his information . If a cont rolle r must use a keystroke or search t hrough manuals, NOTA MS, METARs , etc. to f ind specif ic information, the infor mation presentation is then availab le at the discretion of t he controller . This is the case w ith the 0D 1D Ill/IV system, w here a slew of the mo use over an object hig hlight s t he requested infor mation . The third form of informat ion presentat ion is that of system di screti on . In this case th e system or softwa re may prov ide t he informati on when, accord ing t o its determinatio n, it is relevant.

For exam ple in t he U S , the M inumum Safe A ltit ude Wa rn ing (MSA W ) system prov ides inform at ion to th e contro ller reg ardi ng an aircraft 's posit ion relative to mountainous terr ain .

These sources provide the controller w ith a rich assortment of data. Because of this variety and the complexity of a controller's decision making in managing air traffic, it is difficult for a system designer to create a system that wi ll meet the information needs of controllers appropriate ly. As previously described, decision-making too ls and aids are curr ently being developed and fielded to assist the controller in managing traffic. In order for designers to create an interface that includes these tools as well as all other information regarding the air traffic and airspace, it is necessary to determine the information requirements of the air traffic controller. These requirements include not only the information that is needed by the controller in doing his/her job but also how often the info rmation is needed [24] .

This guidance from current air traffic controllers will allow designers to create a system that allows controllers to perform safely and efficient ly in an ATC environment of increasing traffic and complexity With the support of NASA Ames Research Center (Moffatt Field, CA , USA), we are conducting research on the design of eff icient interfaces for controllers . This issue of The Controller provides directions for obtaining a copy of our questionnaire which w ill allow designers to understand controllers' information requirements. The questionnaire is divided into several ATC tasks The respondent is asked to complete tw o tasks. For each of these tasks, flo w charts are provided to clarify the procedures involved that t he quest ionnaire is attempting to addr ess.

The quest ionnai re asks for the opinions of contr ollers regarding their infor mation

requirements under three levels of CNS/ ATM, which extend from tod ay's operational environment t o a pred icted future environment near the year 2015. These levels are described in the questionnaire in terms of the available technolog y such as datalink and satellite navigation, as well as the ATM procedures and support too ls to perform under each of these CNS/ ATM leve ls.

Participation of air traffic controllers in completing this questionnaire will allow us to gain a better understanding of the information needs of the controller. This in turn will lead to seamless integration of the automated tools described . previously into interfaces that w ill allow controllers to interact effective ly and safely with future managed airspace [24] .

Conclusions To meet the twin challenges of increased capacity and improved safety, the future ATC system will need to incorporate many new automated systems. If these systems are to be successful, they must be designed for proficient use by contro llers.

We have outlined procedures by which appropriate typ es and levels of automation can be designed for ATC systems.

Controller information requirements must also be taken into account in developing the interfaces that wi ll integrate these automated tools with future ATC systems Finally, in this article we have considered human factor s issues related to ATC automation and interf aces only in the design and implement ation stages For new systems to be trul y successful , human factors assessment must cont inue into the stage w here systems are fi elded [10] This must be follo we d by evaluation during actual operations, leading , if necessary, to design revisions [6)

, H CONTROLLER

Thanks also to Diego Castano, Scott Galster, Anthony Masalonis, Ulla Metzger, and Feng Wang, for their contributions to this work.

References 1 2 3 4

5 6

7 8

9 10

11 12

Aviation Week and Space Technology (1998). Answers to the Gridlock.

(February 2, pp. 42-62).

Eurocontrol (1998). Operational concept document. Brussels, Belgium: Author.

Flight Safety Foundation (1997). Aviation statistics. Washington DC: Author.

White House Commission on Aviation Safety and Security (1997). Final report to President Clinton. Vice President Al Gore, Chairman. (February 12). Washington DC: Author.

RTCA (1995). Report of the RTCA Board of Director's Select Committee on Free Flight. Washington DC: Author.

Wickens, C. D., Mavor, A., Parasuraman, R., & McGee, J. (1998). The future of air traffic control: Human operators and automation. Washington DC: National Academy Press Duong, V. (1996). Dynamic models for airborne air traffic management capability: State-of-the-art analysis. Bretigny, France: Eurocontrol.

Gent, R. van, Hoekstra, J. M., & Ruigrok, R. C. J. (1998). Free flight with airborne separation assurance. In Proceedings of the International Conference on Human Computer Interaction in Aeronautics. (pp. 63-69).

Montreal, Canada: Editions de l'Ecole Polytechnic de Montreal.

Eurocontrol (1998) ATM Strategy for 2000+ Draft issue 3.0. Brussels, Belgium: Author.

Harwood, K., Sanford, B.,D., & Lee, K. K. (1998). Developing ATC automation in the field: It pays to get your hands dirty. Air Traffic Control Quarterly, 6, 45-70.

Hopkin, D. (1995). Human factors in air traffic control. London: Taylor and Francis.

Parasuraman, R., & Riley, V. A. (1997). Humans and automation: Use, misuse, disuse, abuse. Human Factors,39, 230-253.

13 Mundra, A. (1989). A new automation aid to air traffic controllers for improving airport capacity. (Technical Report MP-89W00034). Mclean, VA: The Mitre Corporation.

14 Erzberger, H., Davis, J. T., & Green, S. M. (1993). Design of centerTRACON automation system. In Proceedings of the AGARD Guidance and

Control Panel, Symposium on Machine Intelligence in Air Traffic Management. (pp. 11-1 -11.-12). Neuilly-sur-Seine, France: AGARD. 15 Sheridan, T. (1980). Computer control and human alienation. Technology Review, 10, 61-73.

16 Wiener, E. L. (1988). Cockpit automation. In E. L. Wiener & D. C. Nagel (Eds.) Human factors in aviation. (pp. 433-461). San Diego: Academic Press.

17 Endsley, M. R., & Rodgers, MD. (1998). Distribution of attention, situation awareness, and workload in a passiveair traffic control task: Implications for operational errors and automation. Air Traffic Control Quarterly, 6, 21-44.

18 Parasuraman, R., Molloy, R., & Singh, I. L. (1993). Performance consequences of automation-induced "complacency.¡ The International Journal of Aviation Psychology, 3, 1-23.

19 Cohen, M. 5., Parasuraman,R., Serfaty, D., & Andes, R. C. (1997). Trust in decision aids: A model and a training strategy. (Technical Report USAATCOM TR 97-D-4). Arlington, VA: Cognitive Technologies Inc 20 Parasuraman,R., Mouloua, M., & Molloy, R. (1996). Effects of adaptive task allocation in monitoring of automated systems. Human Factors,38, 665-679.

21 Hilburn, B., Joma, P.G.A.M., Byrne, E. A., & Parasuraman, R. (1997). The effect of adaptive air traffic control (ATC) automation on controller mental workload.

In M. Mouloua & J. Koonce (Eds.) Human-automation interaction: Researchand practice. (pp. 84-91). Mahwah, NJ: Erlbaum.

22 Endsley, M. R., Mogford, R., & Stein, E. (1997). Effect of free flight on controller performance, workload, and situation awareness. (Technical Report). Atlantic City, NJ: FAA Technical Center.

23 Galster, S. M., Duley, J. A., Masalonis, A. J., & Parasuraman, R. (1998).

Effects of aircraft self separation on controller conflict detection performance and workload in mature free flight. In M. W. Scerbo & M. Mouloua (Eds.) Automation technology and human performance: Current research and trends. (pp. 98-101). Mahwah, NJ: Erlbaum.

24 Duley, J. A., Galster,S. M., Masalonis, A. J., Hilburn, B. G., & Parasuraman.

R. (1997). En route controller information requirements from current ATM to free flight. In Proceedingsof the 10th International CEAS Conference on Free Flight, Amsterdam.

NASA/CUA Questionnaire: Controller Information Requirements in future CNS/ ATM systems If you would like a copy of the questionnaire then please either:

send this form to: Jackie Duley Cognitive Science Laboratory Catholic University of America 2500B Washington DC 20064

Name: Address to which questionnaire should be sent:

USA

or FAX this form to:

ATC Unit at which you work:

Jackie Duley Cognitive Science Laboratory FAX number: 001 202-319-4456

Experience in ATC:

or alternatively e-mail the information required to: 21duley@cua.edu

'

!~---------------~-------

i 111:CONTROILILER

15

ree Flight One Controller's Perspective The text of a recent presentation to the Royal Aeronautical Society at Loughborough University in the United Kingdom, by John Levesley What do we mean by Free Flight?

There are Free Flight Fundamentalists to whom t he Free Flight Concept is a Ho ly Grail I They forese e Free Flight as a means w hereby, one day, an aircraft w ill have the ability to depart from wh erever and w henever it wa nts , fly profiles of choice fo r th e duration of the flight and to land w herever and wh enever it wa nts . As it assumes that we can remov e any reliance on airports, and th at w e have weath er contro l, and are largely em ergency fr ee it is somewhat impractical in the near term , but long er term, wh o knows7 Should we even try to pursu e this Holy Grail?

The mediaeval roman ces of King Arthur, Camelot and the Knights of the Round Table describe the Quest as be ing as important as the finding of the Grail. Many of the knigh t s discover ed a wh ole range of won ders in t hei r quest for the Grail though not the Grail itself To use a mo re modern analogy Presiden t Kennedy set t he targ et of a moon landing before the end of the decade as a Holy Grail to Unit ed States' scientists, eng ineers and industry. Even if t he landings had failed, or occurred later, the tech nological and scientif ic discover ies and achievements of that Quest gave t he Unit ed States an edge wh ich it has not yet lost.

In each case t he search for t he Grail was as importa nt as f ind ing it, and the spin-offs from t hese quests brought forward new and unexpected benef its and advances.

If we strive for th e fundamenta lists · visio n of Free Flight we may fail , but we may discover won ders and achievements along the way that advance the nav1gat1onof

16

air transport around the world in ways that we cannot even begin to guess at.

What is so different about Free Flight ?

For many years navigators and pilots have striven to t ravel by the shortest route between tw o po ints . In the last twenty ye ars, the instal lation of advanced flight management syst ems in civil transport has made it easy for those aircraft to fly circle routes, so why don't the y do it?

Airspace restrictions.

Danger areas, training areas, prohib ited and restricted areas, national boundaries and nat ion al interests .

Air Traffic Control systems capability. Exist ing ATC systems all depend on estab lishing common references betw een aircraft wh ich can be compared to detect and resolve confl icts.

A ircraft on direct routings deviate away from such common reference po int s, w hich gives a controller noth ing with w hich to antic ipate conflicts. A contro ller, therefore, has to allocate an excessive amount of time to monitori ng aircraft under t heir control to spot and resolve confl icts . Thi s in turn creates a very high w orkload and is one reason w hy militar y control lers invariably handle less aircraft in tran sit than a civil controller as militar y traffic flies a series of near random ro ut es as th e norm , w hilst civil traff ic, as the norm, is restricted to t he route structure .

In fact many civ il co ntro llers do , at t hei r pers onal d iscretion, provide direct routings to aircraft w hen they can be conf ident t hat it is safe to do so and t hat their workload w ill not become

excessive. Thi s is most frequently in the uppe r airspace, at night , or at weekends or on public hol idays when military traffic and activity and airspace restrictions are at a minimum.

Free Flight imposes a further complication in that an aircraft wil l not fly just a direct (Great Circle) rout ing but an ind ividually der ived and more complex trajectory, and will propose updates to that trajector y several (many?) times in its flight to enable its compliance with company or pilot determined c·riteria.

To contro l effective ly large vo lumes of direct rout ing traffic is currently beyond the capabi lity of existing ATC systems. Yet in a speculative Free Flight env ironment the assumption is that a convent ional grou nd based ATC service will be expected not only to separate Free Flight aircraft from each other, but also non-Free Flight capable aircraft from each other, and additiona lly Free Flight from non-Free Flight capable aircraft .

Why Free Flight?

A Great Circle or direct routing equals the shortest distance between two points, but it may not be the fastest or cheapest route . It is norm ally flo w n in level flight and at the same level and speed for the vast majority of the time . It is a one shot option , a direct route is a direct route is a direct route ..

A Free Flight route can be the shortest duration route , the shortest dist ance , the cheapest, or more likely an optimum route that plays off all of t hose issues against each ot her to come up w ith the overal l best option . Moreo ve r, it monitor s its trajectory and if any signif icant criteria change ,

then it w ill seek to amend its proposed trajectory. Th ese proposed trajectories may seek to change one or more variab les from track , speed and leve l - indeed level flight may only be attained for a short period of the flight.

Examples of crit eria for Free Flight trajectory amendment proposals might inclu de the avoidance of a high cost ATS provider, ensuring that suffic ient time is available to comp lete onboard catering arrangements, achieving t he lowest cost trip, avoiding airspace closures or bad weather.

Solutions to achieve Free Flight.

It needs to be recognised that there is no one sing le solution to Free Flight . The methods of achieving and faci litating Free Flight wi ll inevitably vary w ith locat ion, phase of flight, technology, investment etc. Neither is it likely to be f ully implem ented everywhere immediate ly. The process will be incremental, and will be dependent on new and inno vat ive techniques of flexible airspace utilis ation, division and management and adequate runway and facilitation provis ion w ithin the ground infra structu re t o permit Free Flight to achieve its economic potential. In t urn , any inevitable environmental impact versus cost, benefits free market debate, wi ll lead to po litical invo lvement.

There are howe ve r three broad ly agreed methodo logies for im plementing Free Flight • Ground based • Cockpit based • Partnership schemes

Ground Based Solutions The A ir Traffi c Contro l equi valent of Free Flight, our

, , CONTROLLER

own Holy Grail is called Conflict Free Planning, the best example of which to date has been demonstrated in simulation as part of the Eurocontrol PHARE programme dealing with future concepts for en-route control.

The latest demonstrations of this concept (in August 1998) have begun to suggest a framework within which a direct routing and possibly even a Free Flight environment might be implemented within the upper airspace. National Air Traffic Services Ltd have conducted this work in the UK for Eurocotrol. The simulator used is situated at the Air Traffic Management Development Centre at Bournemouth Airport and is operated by the Department of Air Traffic Control Systems Research. Further demonstrations of a yet more advanced PHARE concept were programmed to be demonstrated at the Netherlands Aerospace Research Centre (NLR) in November 1998.

The August PHARE simulation, (probably for the first time) did genuinely deliver a system that showed real promise and potential for development for use in high level en route control. It did control traffic on direct routings effectively, and workload was noticeably lower when controlling levels of traffic typical of a busy day at current traffic levels enhanced by both direct routings (up to 50% in this case) and up to 75% further augmentation, albeit because the traditional ATC role and task was noticeably changed.

This PHARE demonstration assumed the availability of RVSM in domestic airspace, that 70% of aircraft were equipped for RVSM, had 4D FMS and were ATN datalink equipped. The simulation assumed (arbitrarily) that those aircraft with the appropriate equipage and which wished to fly above FL295 could do so and could fly direct routes.

Those 30% of aircraft, which

1 · 11

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were not so equipped were constrained to a maximum FL of 290 and to flying on route (including BR Nav. and conditional routes).

Controllers worked with a series of advanced tools, plus datalinks and electronic inter controller co-ordination. There were no flight strips, paper or otherwise. The PHARE tools did not require a controller to monitor or scan the traffic situation nor to detect conflicts. The tools make no contribution to sustaining a controller's picture. The controller's role is to resolve conflicts predicted and identified by the tools, whenever possible by conflict free planning. The fundamentals of the concept are:

The use of datalink to provide: • • • • •

certainty of intention trajectory prediction proposals of trajectories validation of proposals approval by command.

The used of advanced controller support tools and automation to provide: • Conflict free planning • Conflict probing and medium term conflict alerts (Conflict Detection) • Deviation monitoring • Problem solving • Support new concepts of eligibility between controllers and between controllers and pilots.

One of the most disconcerting things about the tools is that they encourage ATC practices that are currently (and rightly) regarded as reckless. Multiple opposite direction unrestricted climbs and descents don't need intervention if the tools show the trajectories are separated. Five mile crosses don't need two miles extra for the pension and kids.

The overall PHARE concept no maintenance of the controller's picture, no controller conflict detection,

no geographical reference, safety critical software - poses not a few challenges to ATS providers and for their regulators. How will they cope with the safety management, regulation and certification of safety critical software which works in such a way that it excludes the use of the controller to recover the situation in the event of a failure - indeed any attempted manual reversion and intervention may make the situation worse. The concept is at the heart of a production line approach to ATC with inherent problems associated with the move to mass production likely to be experienced as they have been in other industries. There would be a need for ATCOs to relinquish skills and acquire new ones. This is neither unreasonable nor is it new.

However this is possibly the first time that a large number of controllers will be asked to relinquish cherished core skills in order to take up a very different and possibly less satisfying role.

If we assume a ground based ATS will be tasked with the delivery of an ATM system capable of controlling 4D traffic on direct routings effectively, then the PHARE concept showed promise and potential for development for use in high level en route control. The ground based system should theoretically be able to function in a similar manner for Free Flight, but revised trajectory proposals may be more frequent and not received and serviced just within the planning phase of the flight.

The August 98 version of the PHARE concept has only been tested in one type of airspace, it should not be assumed that it is the answer to everything everywhere. It does not always work as smoothly with fixed route traffic, and its derivatives have not been fully developed and tested for use in terminal control airspace or in that transitional airspace that it is

expected will be required between free routing and fixed routing and/or Terminal Control environments. Airlines tell ATS providers that they also want optimised capacity and regular predictable performance at airports. To achieve this will require sophisticated traffic management tools and techniques in Terminal Control. It is easy to see that over relatively short distances, perhaps Paris to Amsterdam, by the time departure management out of Paris finishes, arrival management into Schipol may be starting with no room for Free Flight at all. Indeed the greater challenge may be to ensure that Paris's departure management process finishes before Schipol's arrival manager tries to superimpose its will on the flight.

PHARE demonstrations scheduled for November 98 in the Netherlands will seek to address Terminal Control requirements as well as enroute, and will have further non-intervention conventions built in. Indeed a 4D, RVSM and ATN equipped flight for which the tools detect no conflicts will not even be offered to or between controllers. The air and ground based systems will conspire to handle conflict free trajectories without controller or pilot intervention.

The conventional wisdom of a tactical/planner task division is proving inappropriate to the PHARE concept. The new team relationship needs some detailed consideration and study. The current and former ATC roles which perhaps equate most closely to PHARE are the control by exception techniques used by Shanwick Oceanic Control Centre, shared airspace/data concepts like those used in the old London Terminal Manoeuvring Area concept of operations of a few years ago or the procedures employed in domestic airspace in the 1950s and early 1960s when ATC

17

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FreeFlight systems used procedural controllers with task delegation to radar controllers as required. One suggestion (an initial terminology for which was produced by Martin Cox of the NATS Human Factors Unit at Bournemouth Airport in the UK) is that the controllers' roles could be divided between conceptual and real time functions.

Its also evident that there needs to be some pretty clever "interface in the cockpit work" conducted under the PHARE programme. It is not so advanced as the ATC wo rk and the best way to utilise a glass cockpit to support this concept is not yet complete. Nor is the def inition of the pilot's role.

Neither Free Flight nor PHARE need a pilot to propose a revised trajectory, nor do they require a pilot to accept traiectory proposals from ATC. Ground and air systems are well able to validate the proposals and to implement them.

Airspace management You can take various approaches to airspace sectorisation in a Free Flight environment: • You can have fixed geographic sectors - not particularly efficient.

• You can have geographical sectors w ith a degree of dynamic flexibility in their definition.

• You can have a w ide area series of symmetr ical sectors of a similar shape and size w hich tak e no account of geography.

• You can have no fixed sectorisation at all.

• The use of speed contro l in en route flight needs distance to be effective, yet could be a most subtle and effective technique en route, but airspace design and dep loyment wo uld need to be different fr om the present.

To suppo rt these cellular concepts of service needs two new element s in the ATS equation .

18

• A planning controller overseeing strategic demand across a wide area of sectors - the so called Multi Sector Planner who would take responsibility for traffic distribution initiatives from (say) two hours before entry into the cluster of sectors, until the aircraft enter the planning horizon of the first sector's planning controller.

• Consideration of aircraft using datalink to announce their impending arrival automatically and proposed trajectory early by virtue of a so called downstream clearance rather than reliance solely on a ground based flight data processing system.

Whatever scheme is devised, in a Free Flight environment, sector definitions may need to be flexible in size and location, in order to react to forecast route demand and choke points. Controllers and their areas of responsibility become deployable resources as required . We may need to accept that the ex isting concept of FIRs (or at least U IRs), fixed control authorities and geographica l constraints may be redundant in a Free flight environment, or a barrier to its imp lementat ion if retained

This article deals with flight in regulated environments, or mandatory control areas in the upper air space. It has not touched on flight in lower and middle airspace levels in the open FIR. Theoretically at least the open FIR already supports the concept of Free Flight, and it may we ll be that the next category of proposed Free Flight implementation, looking at cockpit based solutions, will be applicable to the open FIR.

Cockpit Based Solution Where would we use a cockpit based solution to enable Free Flight7 Some Fundamentalists maintain that there is no need for a ground based organisation at all; off into the blue, switch on the collision avoidance system and wing it guys, the right stuff rulesl Controllers have some reservations about this approach. There are, however, many areas where a cockpit based solution may be of real value, when no alternative exists in the form of a sophisticated ground based system So where wou ld we use it? Over those continents w ith under funded and poorly equipped ATC organisations (the wor ld's major oceans are actually quite well controlled)7 In the open FIR, below FL2457 So let's look at the pros and

cons of a cockpit based solution.

70% of the world's surface has no surveillance or much VHF or UHF radio coverage.

Unfortunately large portions of those regions also have unsophisticated ATS services.

Too many of my colleagues around the world are grateful for a serviceable locator beacon, reliable VHF R/T and the provision of a phone, fax or teletype to send and receive flight plan, NOTAM and weather information - too many of them have, all to often, a lack of some (most?) of these essentials. No matter how committed they remain to providing a decent service, their infrastructure provision fails them again and again.

Surveillance capabilities and computerised systems are just a pipe dream. Their chance of providing a wide area en route separation service is limited .

As a result a great deal of effort has been put into developing strategic control systems that do not require a large terrestrial infrastructure.

The most mature is Automatic Dependent Surveillance (ADS) which provides automatic position reporting and controller pilot communications via variou s datalink communications media including satellite relays A secondary service deri ved from ADS is the ability to broadcast all position reports between participating aircraft and to display the positions and idents on a geographical display in the cockpit. This system, known as ADS B, was used during the Atlanta Olympics to enable helicopter pilots operating over the city to separate themselves It is one option for a cockpit-derived solution to enable Free Flight, as we ll as an alternati ve to TCAS. Of course such systems are dependent on all aircraft in t he area being equipped and t hey raise other issues. Ther e is considerable debate about the issue of CFiT, and its causes Do pilots want yet another device that may enhance their

11 CONTROLLER

situation awareness about other aircraft yet serve to distract the crew from the primary task of flying the aircraft? What happens in an emergency when the crew might wish to relinquis h the task? Can a crew permanently sustain a much wide r awareness hor izon in respect of the relative position of a number of aircraft which are all interacting w ith each other? One advantage of an ATC system is that the control ler has a horizon of per haps 120 miles, and is interacting with ot her control lers in adjacent airspace. A contro ller's undivided attention is given to the task, and the contro ller can derive simple solutions to complex prob lems, for examp le five problems are identified, one solution solves them all. The likelihood of ADS B bei ng able to support a comparable combined strategic and tactica l appreciation of problems and solutions is doubtful, but its potentially a lot better than nothing or relying on a safety net like TCAS. Partnership Schemes We 've suggested that there are contro llers who think that enabling Free Flight is a ground based prob lem and that there are pilots who think the answer is to base the solution in the cockpit. There is however a th ird way. It wou ld involve pilots and controllers in an exchange of

0

it

skills and responsibilities with all the emotion that that cou ld engender . It assumes that the person best able to implement it carries out each task in Free Flight. Lets be contentious, lets think abo ut contro llers navigating the aircraft in some phases of flight and pi lots resolvi ng the co nflicts arising in those same phases of flight.

In a Free Flight system, using PHAR E in the en-route phase of flight we've already said that: • The aircraft can recalculate and propose new trajectories without the pi lot's interventio n.

• ATC can approve or amend those without the pilot's part icipat ion (other t han a command veto[?] ).

• Similarly PHARE can detect confl icts.

• The contro ller has the ability to desig n confl ict free trajectories that shou ld however ideally be a minimum interve ntion to the trajectory, and wh ich requires the control lers to know a lot more about flight trajectories than now.

• Pilots know a lot about trajectories and if they were presented with the problem and all its repetitions the y shou ld be able to fly a much more subtle solution than the controller cou ld design and up link.

Maybe we have a situation where the contro ller detects a prob lem, and accepts the

trajectory subject to the pilot accept ing a conflict for resolution pointed out by ATC to the pi lot. The pi lot can view the problem via ADS B or from a real time uplinked and updated presentation from the ground system. The pilot can accept the task or reject it and let the control ler adjust the trajectory instead. This may be particularly appropriate when using these too ls in a termina l area, w here the pi lot takes the arrival management information and advisories inboard, and flies a "virtual visua l" approach with all traffic disp layed by ADS B or similar.

Summary If we take the least contentious approach, that Free Flight will initiall y be an en-route imp lementation by a grou nd based ATM system , where are the tools com ing from?

We already have Flight Data Processing (and the possibilit y of airborne augmentation or partial rep lacement of FDP by dow nlinked dat a).

We already have Radar Data Processing and the development of enhanced surveillance techniqu es v ia Mode S radars and A DS. We are close to t he operational integration of FDP and RDP and the netw orking of that data.

Through th e FA NS1/ A datalink system w e already have datalink fo r A utomatic Position Repo rting and ICAO's

Aeronautical Telecommun ications Netw ork is now starting to achiev e t ruly g lobal acceptance enabling more full y featured datalin k services.

The PHARE programme is developing emb ryo en rou t e contro ller and pilot interfaces and an outline but pe rhaps contentious operationa l concept, w hich migh t sup po rt direct routings and perhaps Free Flight .

Versions of the firs t operat ional CNS too ls, A DS and CPDLC are on opera t ional trial and !CAO complian t systems are targeted for introduction on the North Atlantic early in the next decade.

Also in the North Atlan t ic , the cur rent Shanw ick upgr ad e prog ramme w ill brin g in all the building bloc ks t hat are required fo r t he PHARE sy st em.

It is possible to conce iv e of the use of a der ivation of PHA RE to enable direct ro ut ing s o n the No rt h At lant ic.

So wi th many cave ats and depend encie s, it is just possible to conce ive of a Free Flig ht system pro vi de d by a t radit iona l g roun d based AT C syst em over the At lant ic and perhaps later in t he upper airspace of Europ e by say 20 15 . In pr incipl e we should be able to make it w o rk, but t here are so many entrenched positio ns, cult ural d ifferences and tra d itional prej ud ices to overcome that the techn ical challeng e may be qu ite minor in co mpa rison .

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11 CONTROLLER

April

'99

Singapere

E:xpe Centre,

Sin§Japere

19

Free Flight A Pilot's Viewpoint By:Captain Peter M. Foreman, Chairman,Air Traffic ServicesCommittee International Federation of Air Line PilotsAssociations

"Free Flight" may involve flight, but it won't be free.

Aircraft will not become as free as birds, and air traffic management will not be cost-free.

T

capabilities and procedures in a new concept called air traffic management (ATM) . The FANS Committees' recommendations have been accepted and developed by !CAO as CNS/ ATM. The understanding of how to build CNS devices, exceeds the present und erstanding of how to use them to best effect to realise our goals in a fully deve loped CNS/ ATM system.

Getting t here wi ll be an incr emental evo lut ionary process , but impli cit in the ICA O CNS/ ATM vision is a safe, dy namic and flexible operating env ironm ent which

he RTCA Select Comm ittee wer e the first to institut ionalise the word s "Free Flight," but the idea of freedom of flight is much older. Freedom is an ideal state for all beings, but that is not the motive for Free Flight. Our long held objectives are impro ve ments in air safety, airspace capacity, operational efficienc y, flexibility and economics.

Would w e sacrifice any one of these objectives in order to gain freedom7 Wou ld freedom be the best way to maximise these goals7 Wou ld a cooperative air-ground system or

Strat egic Separation No Conflicts High

G uara n teed Sepa ratio n

j:

Tactical Separation Confli ct'i Resolved

D~¡nam ic Density

4D Contracts Inflexible

Low

Free Flight Flexible

Free Flight

Figure I: The Free Flight Conti nuum

autonomo us airborne systems be superior7 Science fict ion aside, the International Civil Aviat ion Organization, Future A ir Navigation System (ICAO, FANS) Comm ittees , wh ich started t heir wor k in 1983 , were t he f irst to define improvements in techno log ies for communications , navigation and surve illance (CNS), to support other enhanced techno logi es,

20

appropriates the technical aspects of CNS/ ATM and bestows a name with political cachet to act as a magnet for funding, is to be applauded.

Free Flight is not just a state of bird-like freedom. There is the concept of a Free Flight cont inuum (Figure 1), whi ch encompasses all modes of operation of the ATM system over the next several decades.

At one end of the spectr um is a strictly controlled state of enhanced ATC. At the far end of the spectrum is the distant goal of bird-like Free Flight. In between, is the w hole range from present to possible futur e

capabilities wou ld determine w here on the Free Flight continuum a flight would be required to operate . As dynamic density increa ses, flights would be subject to more and more control. On the other hand, where dy namic density is a minimum, flights wo uld be permitted the greatest degree of freedom .

The concept of dynamic density requires development into objective metrics . Air traffic numbers and complexity are important components of dynamic density, but as the means of modulating the mode of ATM or Free Flight, additional factors must be t aken into account. The list w ould include , but not be limited to, terrain, special use or restricted airspace, weather, ot her flight hazard s and predicted air traffic

cou ld be character ised as Free Flight .

ICAO 's initiatives are saddled w ith t he co llective name CNS/ ATM . Pilots, engineer s and air traff ic contro llers, w ho understand CNS/ ATM, should sympathise w ith t he programme manager w ho has to go before a board of directors , or a f inance committee , and plead for funds for "CNS/ ATM " To the extent th at Free Flight

Figure 2: Free Flight and CNS/ATM

operat ions.

The opt imum operating mode on the continuum ensures guaranteed separation w ith the maximum degree of freedom appropriate to the dynamic density. !nits simplest terms dyn amic den sity is expressed as a function of traffic density and traffic comp lexity. Dynamic density coupled w ith ATM/Free Flight

requirements.

Dy namic density is not likely to lend itself to calculation on an airborne platform Th e arbiter of the current and pred icted value of dynamic densit y should be the control ler w it h the aid of his support systems If there is any need for pilots to know t he dynamic den sity, they could be info rmed from the ground , but

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CONTROLLER

Perception of Traffic Situation

Reception and Comprehension

Q ~~ ;." .

Instruction

Conununication

-----.

' Figure 3: Present Single-Channel of Decision and Action

it is more likely that pilots would have no direct need for this information . Rather, it would be a tool used by the controller to modulate the level of control and the nature of clearances, instructions and authority issued by the controller to an aircraft.

Free Flight contains everything in ICAO CNS/ ATM (Figure 2), but there are additional elements of the Free Flight programme, some of which require discussion.

Bird-like flight might be a vision for the development of ATM. However, it should not be the immediate objective.

We need to take incremental evolutionary steps towards our goals and appreciate the progress which we make.

Success should not be measured with birds as the yardstick.

Free Flight has spawned the mantra that every step which removes a restriction to flight is a step towards Free Flight.

That notion has become the rationale for a number of illconsidered developments, including the use of TCAS II in-trail climbs, high-altitude VMC climbs and reduced oceanic separation based on FANS-1/ A. These programmes are said to be a part of Free Flight, but they are not part of CNS/ATM The Wright brothers ' first flights were free . For years after, so were most other flights But, it soon became evident that to achieve an acceptable level of safety and a sound economic platform for aviation , some fl ight freedoms

II CONTROLL ER

had to be sacrificed in favour of control.

If we decide bird-like flight is possible, the next question is should we do it? ATC is extremely effective, but from time-to-time aircraft still collide or come too close to each other. It is possible to analyse these instances and find some person or component at fault and suggest that if they were improved then there would be no re-occurrences. However, if one looks beyond the cause of individual failures, one finds that the system is capable of failing because it has only a single-channel (Figure 3) for safety decision making and action.

The air traffic controller and his support systems have situation awareness of the air traffic. They make traffic separation decisions and communicate these decisions to the pilots The pilots are then required to act upon these communications to achieve the separation.

A weakness in this singlechannel system of decision making and action is that full knowledge and situational awareness are not shared between the controller and the pilot. In some cases a surveillance system provides the controller with feedb ack on the implementation of his decisions. With surveillance the ATC system is more robust and flexible, but decision making and action is still single-channel and prone to a single-point failure .

TCAS II is not as good as ATC in keeping aircraft apart ,

Figure 4: Redundant Second Channel for Decision and Action

its effectiveness lies not in its performance, but in the fact that it is an independent redundant second channel.

Please note that TCAS II only attempts to prevent collisions, it does not provide ATC separation. TCAS II is introduced here solely to illustrate the argument that a two channel system is more reliable and robust than a single channel system.

The CNS technologies will provide enhanced situation awareness on the ground and in the cockpit . They open up the potential to have a redundant airborne independent second channel (Figure 4) of traffic separation safety decision making and action. That will go a long way to closing off any residual loop-holes in the ground based systems and provide airborne separation assurance to back-up and support the ground based systems. The greater robustness of such an architecture wi ll "cut the tails" of a number of the collisionrisk model probability scenarios and make for a safer, more flexib le and higher capacity ATM environment

with reduced separation minima .

To use CNS/ ATM technology in the autonomous aircraft mode under normal operations is to revert to a single channel system. Pilots do not subscribe to autonomous flight (Figure 5) as a normal mode of operation, yet we appreciate its benefits for non-normal operations.

Autonomous flight should be held in reserve to provide separat ion assurance and an airborne capability to mitigate ground system and network failures and provide for graceful system degradation.

The argument that Free Fligh t will permit a reduction in ATC services is an economic argument, it is not a safety one.

In certain sit uations, pilots can apply separations between limited numbers of aircraft The question is, shou ld the safety of air traffic separation depend solely upon pilot actions? Pilots are not air traff ic controllers . Pilots are responsible fo r the safety and operation of the ir aircraft and all on board . Pilot s should retain that responsibilit y Air

Perception of Traffic Situa tion

,,___,,......,.-.

...---._

-+ +

"

Figure 5: Single Channel ..Autonomous .. Flight

21

Free Flight ---~-

Unknown Traffic

-1~, I I .l -I 1'.,__ 1l~n I I Zone _.,.

1

---=-~--~--~~- . .

..

Figure 6: Free Flight Protected and Alert Zones

traffic controllers are responsible for maintain ing a safe and appropriate separation betw een aircraft.

Controllers should continue to be charged w ith that responsibility. Th is does not mean that pilots cannot take a part in separation between aircraft, indeed they do so today, and that role could be expanded under the right condition s and constra int s.

Piloting aircraft and controlling air traffi c are occupations for we ll t rained , motivated, skilled and responsible persons. The two occupations share exte nsive areas of common knowledg e, but they are very different in t heir execution. Controlle rs work regular shifts of moderate lengt h. Controll ing air traffic is a high menta l workload. Controllers take t urns of two hours or less at a work station int erspe rsed by rest breaks dur ing a shift. The only pilots whose work patterns are similar are shorthaul, high-freque ncy commuter pilots. Pilots, and particularly long-hau l pilots, wo rk very long and irregular shifts of up to 14 hours or more. They do so w ith the added burden of cons iderab le accumulated sleep-loss Pilot s also work w ith intense workloads and mental concentrat ion dur ing some phases of flight. but t hey should not be expecte d to shoulder t he respons ibilit y for traff ic separation d uring other phases of fligh t, nor can the y take on added w ork load where t hey are busy.

Contro llers w ork the air

22

traffic situation in a proactive mod e w ith foreknowledge from the ATC flight data processing system and considerable repeti t ion of similar traffic sequences at a given site. Pilots wor king airborne separation w ould have to do so w ith little foreknowledge in a mainly reactive mode in an ever changing set of circumstances as they moved along a route or from route to route .

There are reasons w hy most controllers have active careers of 25 yea rs or less wo rking w ith live traffic. Controller "b urn-out" is a recognised (if not sufficiently attended) condition. A ir line pilots, on the other hand , tend to have long careers in excess of 35 years. Pilot "burn-out" is rare.

Wh ile pilots have the gre ate st respect for contro llers, we are not vo lunteer ing to change places w ith them or to bring their work into our cockpits .

Controllers must retain the respo nsibility for separation Thi s means that no matte r how much separation activ ity the fligh t crew is invo lved in, pilot s can onl y do so under a clear ance or authorit y issued by a co ntrol ler. It also means that control lers and t heir suppo rt systems must have complete dat a and awarenes s of t he developing traffic situation in suffi cient t ime to exert their contro l aut hority to ensure that they effect ively d ischarge th eir separati on responsibi lity.

Free Flight takes a thr ee-, or even four - , d imensiona l view of airspace as opposed to t he present route -struct ured view.

lnformation

+

Figure 7: Four Zones in Plan View

This is valid in the upper levels, and upper air route freedom is frequentl y granted in several parts of the wo rld today. But, published routes with pre-planned navigation information and terrain clearance are good for th e safety and convenience of flight at lowe r altitudes.

Random routing at low altitudes would require careful and extensive flight planning.

Betw een any two points in the atmosphere, there are an infinite number of possible paths. Only one of these paths represents the pinnacle of eff iciency. It is not easy to predict the most efficient path.

It requires access to considerable computing power in near real-time, to achieve t he maximum potential savings from Free Flight. Unless pilots are to be continually fiddling and adjusting present types of flight management systems, t hey w ill need a "Free Flight" push-button on their flight management systems.

In advance of the tran sition to optimum routings under ATM / Free Flight. consideration should be given to the airspace classifications and dimensions . Present airspace structures are rout e and fix based. If the re is a change to free routing, then all t he airspace should be appropriately classified The advent of CNS/ ATM or Free Flight w ill not substantially reduce the

smallest separation minima applied with radar in the terminal environment toda y.

The largest separation reduction s will be where CNS/ ATM replaces procedural , control. In order to provide for the safe efficient and fle xible operation of aircraft in oceanic and remote areas, the ATM systems there must become more like the domestic radar environment. ICAO CNS/ATM architecture is the way to move forward to improve ATM in oceanic and remot e airspace.

IFALPA polic y calls for the ATC system to provide the basic service of separation between aircraft . Howev er, we envisage that pilots may take on a shared responsibility for short-term or local separation based upon a cockpit display of traffic information (CDTI) w ith appropriate ATM feature s. It is not clear w here the evo lution of such applicat ions might end, but potentially pilots might start by sharing w ith the air traffic controller the responsibilit y for separation in in-trail climb or descent through another aircraft's altitude, station keeping, overtaking and perhaps , one day, fo r simpl e shallow-a ngle two -aircraft crossing manoeu vres The common characteri stic of all t hese scenarios is a zero or low closing speed Protect ed and alert zones (Figure 6) are proposed for Free Flight. but four zones

' tti CONTROLLER

Wake Vortex

Figure 8: "Davey Crockett Hat" for Wake Vortex Protection

(Figure 7), or thresholds, are required. The first to capture "information" on all traffic which may become relevant.

The second to "alert" to ensure that controllers and pilots are made aware of situations which may require their attention. The third for "action" required to ensure that the protected zone is in fact protected, and the fourth and innermost "protected". The proposed shapes are portrayed as near-circles (hockey pucks), in fact they would need to more closely resemble envelopes of the "range over range rate to closest point of approach" concepts of the ACAS algorithms.

Direct collision is not the only hazard, wake-vortex hazards must also be addressed. With large separations, wake vortices are not usually a concern. If separation minima are to be reduced to a few miles, or a 1,000 feet or less ve rtically, then wakes must be recognised and avoided.

Instead of looking like a hockey puck, t he Free Flight protected envelope around an aircraft may look more like a "Davey Crockett" coon-skin hat (Figure 8), with the wake in the racoon's tail .

Various organisations have started to look at the human factors aspects of Free Flight and CNS/ATM. Prominent among these is the Society of Automot ive Engineers, whose G-l0W Sub-Committee on Free Flight has ident ified a number of issues requiring attention .

'I If CONTROLLER

"Control by exception" does not inspire confidence. Unless, a fully competent super-human automatic artificial intelligence system can be given control and full responsibility for separation, human controllers and pilots will remain saddled with the responsibility. It is not appropriate to place humans in an impossible situation and then blame them when things go wrong. This is not the way to meet the objective of a system approaching absolute safety.

To ensure the maximum performance and safety in the system the humans should work co-operatively with each other and the technolog y as recommended by Dr. Charles Billings of the Ohio State Universit y, in the NASA Technical Memorandum "Human-Centred Aviation Automation Principles and Guidelines ."

A key to safe operatio n is maintaining the shared situation awareness of the entire team of pilot s and controllers. This awareness may in turn be shared by their support systems. Situation awareness requires all of the necessary informatio n available in a timel y manner through simple and intuiti ve interfaces.

Likew ise, human inputs to t he system should be through optimised interfaces. The challenge is to ensure that available theoretical work and research is carried forward into system development and implementation.

The system design and procedures should also

recognise the need to keep humans involved with the processes. Howe ver, increased system capacity implies increased interactions, so respect must be paid to w orkload issues. Data processing on the part of the personnel in the air and on the ground should be a minimum; mental numerical data processing should not be required at all.

Traditional flight crew and air traffic controller w ork practices are intended to respect human performance capabilities. Free Flight will change many of the tasks. To the extent that automation takes over some tasks, Free Flight may reduce workload. To the extent that new tasks are created , existing tasks are redistributed, or more comple x monitoring is required, Free Flight may increase pilot and/or controller workload. Before embarking upon the Free Flight ventu re, provisions should be made to measure pilot and controller workload, and mitigate any deleteriou s effects. In some ways the additional work load of an unexpected random tr affic encounter wo uld be similar to that required to navigate around en-ro ute weat her. That addit ional wo rkload is significant and it has to be considered in designing a Free Flight or CNS/A TM system.

Free Flight should only take place in a controlled airspace under the surveillance of an ATM system w ith the capacity to exert contro l in order to ensure the maintenance of an adequate standard of separation between aircraft, and under an authority issued by the controller / ATM system.

Th is might mean a more flexib le style of fl ight than at present, but thi s is not "autonomous flight".

Autonomy in the choice of route should not be confused w ith autonomous separation.

During shared separation responsibil ity, the contro ller should have full knowledge of the situation . The controller should retain the ability to intervene if in his judgement: an adequate standard of separation wil l not be assured; if the dynamic densit y increases above the level permitting continued self separation; or if special use airspace becomes a factor. An analogy fo r shared responsibilit y may be found in manufactu ring , w here indiv idual workers (pilots) produce the product (separation ), under the watchf ul eye of the floor manager (contro ller) who is in turn responsible for the quality of the product , the efficienc y of the shop and the safety of the whole operat ion , and has the authorit y to intervene in the ind ividual w orker's process. Such oversight requires an excellent vantage point and an adequate time frame for observation, decision making and intervention when required.

The operation of shared separation responsib ility in relatio n to time is also critical for the pilot s. If the frequency and du ration of encounte rs is too high , the fl ight crew will become saturated with demands for their attention .

Even before they reach the saturation point, the increase in work load wou ld accelerate the onset of fatigue . Th is wo uld have consequences for crew requirements and flight dut y limitation s.

Safety in Free Flight should not be based on an expectat ion of instantaneou s crew reaction. Shared separation respons ibility should only be used w ith sufficient lead-time for the crew to manage their attention between separation and other crit ical tasks. Th ey should have time to evaluate the traffi c separation situation and consider alternative choi ces

23

Free Flight Conlilluni,cations ~

Sa tellit e /

"\ Tw o-way Sa tellit Yo ice Traffi c

}

Proxi1n ate

Aircraft

~~

Sa tellite Voice A ctive A ircr aft

V HF Bro adcast of Sa tellite V oice Traffic to Proxin1ate Aircr a ft

Gr ound Ea rth Stat ion

Figure 9: VHFBroadcast of Satellite Voice Traffic

before arriving at a decision; to have th e tim e t o negotiat e wit h the other aircraft if th e f irst presented resolut ion is not acceptable, and t he tim e t o respond to any ATM intervention. The lead-t ime requirements of th e crew are compatible with the lead-t ime requirements of t he cont roller wh o oversees th e operati on.

Pilots and controlle rs need a degree of stability and predictabi lity in Free Flight so that they can maintain situation awareness and plan ahead. There should be a model of the intended nominal flight trajectory (N FT) available to pilots and controlle rs. The NFT shou ld represe nt a safe trajectory, and reflect the fli g ht mission. For a transport aircraft th e mission is usually to arrive at the intended dest ination .

For other fl ights such as surveys, tra ining, sight -seeing, or aerobatics there may be other objectives to incorp orate into the NFT The NFT may be further constrained by considerations of te rrain, weather, fl ight hazards, flow management and special use airspace. To maintain a safe, orderly and eff icient fl ow of air traff ic at the arrival aerodrome , an aircraft practising Free Flight should maintain a cont inually valid arrival contract for t he dest ination The basis for this contract would be the NFT The NFT would also be the basis for contingency procedures in the event of system degradat ion

24

A shared land-line telephone service is referred t o as a "party line" . An yone on the line can listen into all calls.

Thi s lack of privacy also applies to ATS radiotelephon y. Pilots and cont roller s gain situation aw areness through the ability to listen t o everyth ing t hat is said on a given frequenc y, enhancing th e safet y and efficienc y of air traffic. In some futur e enviro nment s, all ATS message traffic (data and vo ice) may be tr ansmitted t hrough dat a link systems.

The data links emp loyed wi ll onl y deliver messages to discrete add resses. There w ill be no party line on th e dat a link.

To compensate for the loss of situation awareness w ith respect to routine ATS data lin k messages, pilot s should be sup pli ed w ith a cock pit display of traff ic info rmati on (CDTI) In t hose cases w here dig ital vo ice tr aff ic is also closed , some means should be fo und to restore t he party line .

Where dir ect access t o t hese com mun ications is not pract ical, an auto matic sim ultaneo us air-t o-ai r rebroadcast of ATS digit al voice traffic , on a designat ed V HF freq uency , cou ld be employed to resto re the party line t o all aircraft w ith in V HF range of the voice active aircraft (Figure 9) Before each of the steps in the evolut ion of CNS/ ATM, every individua l who w ill be participating in t he operat ions

w ithin the system will require a level of training appropriate to the level of th eir involvement in the system and their role .

This training should be completed in time for the person to acquire the necessary know ledge and skill before they are placed in a position of responsibilit y for the system and its safety.

Wheth er the system is called Free Flight, or CNS/ ATM, a complete "safety case" is required to validate reductions in separation . It is true th at some exist ing large separation standards are as much empirical as the y are based on analysis.

Nevertheless , these present standards serve us w ell from a safety standpoin t. But, as w e seek to reduce separation minima coincident w ith the w orld- w ide need to impro ve safety, w e have a duty to ensure the safety of th e new minima befor e their implem entation .

The t ransition fr om present systems to Free Flight or CNS/ ATM needs careful planning . ICAO has developed the Global Air Navigation Plan for CNS/ ATM System s. The RTCA Free Flight Action Plan and Government / Indust ry Operati onal Concept fo r th e Evolution of Free Flight come fr om th e Unit ed States.

Eurocont rol has ATM 2000+ One of th e major points to recognise is th at the schedule of enhanced CNS/ ATM capabilit y w ill vary w idely t hroughout the tran sition, both in the air and on the ground, between op erators and from region to region. Lest th e variances are to defeat t he purposes of Free Flight by generating new restri cti ons, air navigati on service providers w ill have to ensure t hat t hey develop t heir systems w it h the flexibility t o accommodate all the t raffi c As regions dev elop t heir systems under th e name of Free Flight or CNS/ ATM,

aircraft w ill continue to move freel y around the world.

Comp atibili ty must be maintained bet w een the aircraft and local air traffic services. Th e best vehicle for this is to impl ement in accordance w ith the ICAO Plan and ot her applicable glob al documents, primaril y the ICAO St andards and Recommended Practices and the various technical Manuals of ICA O. Finally, from a technical standpoint pilot s are still advocating the earliest implementation of ICAO CNS/ ATM. We are prepared to support Free Flight as long as it remains a means to that end, and in the absence of a better slogan, the term continues to be used to promote CNS/ ATM and attract funding for its implementation.

The Author: Captain Peter M . Foreman is the Air Traffic Services Committee Chairman of the International Federation of Air Line Pilots Associations (IFALPA). He is an active airline Captain on a B767 -300ER flying from Vancouver, Canada, to Beijing, Nagoya, London and Honolulu . He is a member of the ICAO ATM Concepts Panel, and Volcanic Ash Warnings Study Group. He is a member of the Society of Automotive Engineers, Aerospace Behavioural Engineering Technology, G10W Sub-Committee on Free Flight. He is a Director of the Air Traffic Control Association Inc. He is also the Canada Air Safety Chairman of the Air Line Pilots Association Internation al. Born and educated in the UK, he received his flight t raining at the College of Air Training, Hamble, UK. He has 36 yea rs of flight expe rience , the past 18 years as Capt ain on DC- 8 , B73 7-200 / 300 , A 3 20 and B76 7 . He also has co-pilot exper ience on th e Vanguard, DC- 6 B, B74 7 and B727.

, I CONTROLLER

38 th ANNUAL CONFERENCE& EXHIBITIONOF INTERNATIONALFEDERATIONOF AIR TRAFFIC CONTROLLERS'ASSOCIATIONS

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CONTROLLER

25

Free Flight Does Free Flight really mean Fear and Folly?

Anthony Smoker n control rooms around the world there are cries of derision and laughter at the perceived insanity of it all. Why should control lers embrac e the concept of Free Flight7 What is th ere to attract controllers to an apparent set of contrad iction s and, if one is to believe som e of what is w ritt en, not a very nice way of controlling aerop lanes?

Time and time again since 1945, there have bee n crie s fo r fundamental change in ATC; for the need to embra ce technolog y to change the w ay that cont rollers carry out th eir jobs_ Time and tim e again contro llers have seen initi atives fai I_ In Euro pe, the capacity so urgently required by aircraft operators w ill come in the near future not from the app lication of technology to change the control process, but by changes to airspace organisation and procedures, in some cases enabled by tec hnolog y_ Such a step change came w ith the introdu cti on of seconda ry rada r and the intro duction of Red uced Vertical Separat ion Minima (RVSM) In other words, precise ly what ATS service providers have been doing fo r the past fifty-five years; the basic w ay that aircraft have been control led w ill be the same _ The current forecasts for traff ic growt h in Europe, as shown in fig ure 1, indicate an inexorab le rise in demand - even w hen the low tre nd is cons idered , t her e has to be a finite po int at w hich squeezing capacity out of the exist ing contro l philosoph ies w ill be reached _ At this po int there w ill most likely be d iminishing retu rns fro m t he t radit iona l capacity enha nci ng measure s in en-ro ute airspace The reality today is that in some parts of the glob e, t he air traffic infrastruct ure is nearer this limit tha n contro llers wo uld like to believe _Particularly when one consider s the long lead ti me and diff icult ies to introduce int o operational service new ATC systems and methods of operat ion ; timescales often In

26

excess of te n y ears_ Therefore , it is ent irely reaso nable , and appropr iat e, to inv estigat e alt ernative app roaches to th e contro l of air traffic now. Free Flight is t he latest repeti ti on of many_ Free Flig ht means many th ings to differe nt people_ It is but one of a num ber of conc eptu al solu t ions to t he proble m of t he shortage of airspace capacity_ It encompasses, indeed one might argue is dr ive n by, fr ustr at ion wit h today's syste m_ It prov ides a very clea r stateme nt of t he aircraft operato r's perspec t ive of what they wa nt, and expect , fr o m the f utu re ATM system_ The fin al report of RTCA Task Force 3 - t he Free Fligh t Imp lem ent atio n task fo rce makes forty -eight reco mmendat ions"_T hese co nta in t he essent ial research quest ions that must be answe red if Free Flight is ever to reach operational implementatio n _Th e report introduces operatio nal concepts that are being , and have been, d iscussed for some t ime_ For examp le, dy nam ic sectorisation of airspace to suit part icu lar traff ic flows and co llaborative decisio n making the aircraft ope rato r act ive ly part icipating in the tact ical flow management decis ions of their aircraft_ It also introduces some new one s, t hat of aircraft self separation - or the transfer of separat ion author ity fro m air to ground, (It is this of course which has attracted the most atte nt ion) and t hat of "Dynamic De nsity"_ Thi s latter concept is def ined as: "the essential facto rs aff ecting conflict rate in both the enroute and t erminal airspace".

The control regime wit hin w hich ti:lat traffic is hand led, the degree of flexibility and free d om that aircraft have to manoe uvre , is governed by the leve l of "Dynamic Dens ity" _ Figure 2 illustrates the contro l continuum in the context of "Dy namic Density " In the field of Free Flight research , it is t his conce pt of and the trans ition from o ne state or

12000

.1 ~ v

I 10000

,.~,

~0

1sooo ~

"-s'it: 6000

#

., er

Traffic Growth Trend s --+- H igh

~

-...... Base Low

,:'?' '

c:::::JActual

0

~ 4000 ยง

"

1 2000 '< 1990

1995

2000

2005

20 15

2010

Figure I: Forecast of ECACGrowth in traffic demand Source: EUROCONTROL' High Dynamic Density

Low Dynamic Density

.

~ -- ----------------- - ------------ -- ---

...

I

I

I

Distributed control litt le ground based interventio n

Ground based Contro l - Struct ured with high levels of interventio n

Figure 2: Dynamic Density and degree of control

Figure 3: Missed connicl and selfseparation events under differing traffic levels and control regimes cont rol regime to anot her, th at leads to a realisat ion of th e scale of the most diff icult tec hnical and huma n factors issues_ A rguably being able to measure Dynamic Density is t he one of th e keys to the success of this concept. At some point, t he Dynamic Density w ill reach a po int w here interve ntio n from the gro und w ill be requi red RTCA recog nise that t here w ill be ti mes at w hich the mature or fu ll Free Flight goa l of flexi bility wil l always be curtailed because of t he traff ic dens ity and comp lexity ; that there wi ll have to be gro und based contro l when the se levels are reached , that

make d istributed or autonomou s contro l unte nable_ W ill a controller be able t o "pick" up t he situ at ion pr esented and th en engage in active contro l per haps having to im pose some for m of structur e on an unst ructu red traffi c sit uat ion , ve ry q uickly, and th en meet t he t argets fo r del ive ring th e aircr aft into te rmi nal airspace7 These are goi ng to be complex, demand ing t asks, and arg uably mo re t ime critical th an eve r befo re, because of t he vo lum es of t raffi c invo lved and t he need t o meet targets aimed at maxim ising ove rall system eff iciency_ M uch of t his is, to co nt rollers, very scary stuff. Free Flight represents a challenge to t he way that ATM is carried out to day, and it really does challenge aspects of t he contro l orocess that contro llers ~onsider sacred It should be evident that the ongoing research into comp lexity and Dyna mic Density has value to the way that we contro l aircraft today _ Free Flight research can

1H

CONTROLLER

provide a new insight into ATC problems today and in the future and provide different directions to follow, or confirm those that are being pursued.

Intuitively controllers will consider these aspects of Free Flight and argue that it cannot be implemented, for perfectly valid reasons. However, intuition is not enough. There must be solid data to support the research to prove that a certain feature will degrade system safety, or provide no benefit in terms of capacity. As an example consider one piece of research that investigates controller behaviour in a Free Flight environment"'. This experiment looked at controller conflict detection performance in two regimes, one where short term intent data from aircraft is not available, and aircraft were self-separating, and one where conflicts are highlighted. Conflict detection performance deteriorated between the two as shown in figure 3. ' Conflicts which are the "bread and butter" of ATC today were missed by controllers. Why did th1s happen?? Researchcontinues to look for the answer, but these results provide a challenge to some of the underlying assumptions that support Free Flight. In this instance it may not be enough to provide just a conflict probe for the controller.

Tthere maY be a need for some other tool to support an acceptable level of controller understanding of even low complexity traffic situations. The mtu1t1vereasons t hat controllers offer, supported by empirical research· are th e key to progress, b ecause they provide the bounds · to which design . · th e 1· 1m1t. solut_1ons can develop. They provide the crucial knowledge with w h.ic h to reject facets of the new concepts. In the example used above it· ·1s·important to note that the ant·1c1pated · performance of human and machine can change·in ways that were never expected - it was an a priori assumption in this study that controllers would still consider conflicts in the way that they do today - the results showed that th ey did not. There is another side to this argument - the research provides the evidence th at will tell controllers that their intuition about a feature of a

'. !I CONTROllER

concept is no longer valid "because of ..... " Some of those ATC sacred cows will change, and change for perfectly sound reasons.

There is a responsibility, therefore, for system designers to ensure that changes to the control philosophies are indeed for the better. There isis scope for changes that are built on the knowledge gained from Free Flight research, that are beneficial to controllers everywhere, not solely in operational environments that use Free Flight.

The provision of capacity to meet future demand can only come from change. The RTCA Task Force 3 report makes it quite clear that the transition and need to move to Free Flight is benefit driven. Controllers should be aware that this means benefits to airspace users. The gains of Free Flight come in reduced operating costs to the aircraft operators, and these in turn come from the flexibility to operate an aircraft in the most flexible way imaginable. This is right and proper, but here lies one of the genuine reasons for cause for concern in the Free Flight initiative, although it is a common flaw in many conceptual studies of CNS/ ATM developments. The benefits of any changes must be there for all of the system user's, from a system that has evolved to meet all of the system user's needs. All of the system user's?

Yes, becausethere is an argument to suggest that the needs of the controllers are often not fully considered. An example of this comes from the Dutch NLR, in an experiment that included the use of an arrival scheduler for an ATC task. During periods of low traffic levels, controllers used the tools; as the traffic levels grew the controllers used the tools less and less. So a tool that is designed to assistthe operator in periods of high workload is not used in these very conditions.

There are a number of potential reasons for this, such as inadequate training as well as the design of the tool itself to meet the needs of the task.

Wiener observed, in his work on cockpit automation , that "it is not what you automate that matters, but what you do not automate". This is one of the most

pertinent questions to ask in considering fundamental change in the control process. It is easy to neglect, in the speed to change and overcome the weaknesses of a system, its strengths.

Future CNS/ ATM systems are predicated on closer integration between air and ground systems.

In order to obtain the much sought after "user" benefits, the aircraft operator must equip their aircraft with technology. In order to realise the benefits, the controller must use the technology to provide the effective control process that is sought. The controller becomes an essential "system" component in the productive function of the ATM process - in other words a system user. As part of the system, the controller has a right to benefits as well. These are often wrapped up in terms of reductions in workload per aircraft movement - forgetting the goal is actually to utilise the workload released, to move more aircraft per controller. It is of course a circular argument.

It is no longer acceptable for design solutions to use the controller to mitigate poor system design or to act as the safety net for inherent weaknesses in the control process. Experience in other safety critical domains, as well as on the flight deck, has taught us much that must be used in the development of future CNS/ ATM systems. If controllers are to function in concepts such as Free Flight effectively, then the benefits must be assessed in terms of the controller, and for that matter the pilot, as well.

This meansthat all those engaged in the design of CNS/ ATM systems need to consider the controller task and activity at the outset. as part of an integral system element. It is no longer appropriate to assign the controller part of an experiment

to a black box on a flow chart.

The tasks and activities of the controller and pilot need to be clearly defined and the operational environment and the interactions therein, as seen from the controller and pilot perspective, must be clearly understood. There are many examples where this is not defined to a level of fidelity so that it precludes an effective design solution.

Free Flight provides the perfect vehicle to ask the question "can we change the control philosophy"? and if not there is the potential to find ways of reducing the effect of a constraint within the control process, which may well be beneficial for use in other operational environments.

The final outcome may not be what the RTCA Task Force envisaged, but it will have acted as the catalyst that led to change and a CNS/ ATM system that really can cater for the growth in air traffic demand.

So, does Free Flight really mean Fear and Folly?

No, it is not a folly. It has come to prominence at a time when it is right to challenge the philosophy of the way that aircraft are controlled. From this could come real benefits to controllers - as well as other system users - today as well as in the future.

Is it to be feared?

Unlike previous eras of ATC development, the cycle we are in now has a much wider consensus to gain, a much wider group of disparate and conflicting interests.

The only way that a CNS/ ATM system can evolve will be by compromise based upon reasoned judgement. In fact by adapting the Wiener maxim - it is not what you change that matters, it is what you do not change. So the answer to the question has to be, very probably!

EUROCONTROL (1998)ATM Strategyfor 2000+ Draft issue 3.0. EUROCONTROL, Brussels ii RTCA(1996). FinalReportof RTCATaskForce3 Free Flight Implementation.

RTCA:WashingtonDC iii Galster,S.M., Duley,J.A., Masalonis,A.J., & Parasuraman,R. (1998) 'Effects of Aircraft Self-Separationon Controller Conflict Detection P,erformanceand Workload in Mature FreeFlight' in Automation Technologyand Human Performance:Current Researchand Trends. LawrenceErlbaum:Mahwah. NJ iv Wiener, E.L.(1985) 'Beyondthe SterileCockpit' Human Factorsvol. 27(1), 75-90 v Joma,G.A.M., (1997) 'Human machineinteractionswith future flight deck and ATC systems'in EngineeringPsychologyand Cognitive Ergonomics,Ed. Harris, D. Ashgate: Aldershot, U.K. vi Wiener, E.L.(1985) 'Beyondthe SterileCockpit' Human Factorsvol. 27(1), 75-90

27

A Christmas Story The Greek ATC Living Museum (19S 0 - 98 ) Philippe Domagala, Contributing Editor

nce upon a time there w as a beaut iful place on earth, home of Zeus and Apollo. Six t housand years ago, one of t he most sophist icated civilisat ions started . They gave us philosophe rs like Plato , invented democrac y and bu ilt marvels such as t he Parthenon.

Ehl Wh at has this to do wit h ATC? W ait , t his is Christmas, I am gett ing th ere.

The Greeks w ere also the inventors of aviation . Yes, Icarus was the fir st av iator. The fact that he glued his w ings w ith the w rong material and fina lly crashed , is beside the point, as th ose litt le technical problems still happen t oday (remember th e ti les on t he Space shuttle 7 ) Greeks toda y love t heir past and like to put everyth ing in museums. Therefo re w hy should th is be any diff erent fo r ATC7 The Greeks bu ilt an ATC system in Ath ens around 1950 which was so sophist icated at the time that t hey decided to keep it int act fo rever, and operat ional even until today.

Imagine Sm long strip bays (see PHOTO 1) not used anymore but still preserved as they were and a ve ry sophisticated telephon e system linki ng all t he ot her airports in the various islands w ith the Control Centr e in At hens (see PHOTO 2) In the Centre, every handset has a diffe rent colour and ringing tone. As thi s system is non-d istribut ive (i e indepen dent) only one te lephone line can fail at any t ime, leaving t he ot her s fu lly operatio nal. The syste m is so brilliant that t hey st ill use it today To talk to aircraft a mod ern telecommunication syste m w as dev ised and built under the consoles. To make for easier maintenance and better cooling, t he w ires connecting the

O

28

var ious boxes w ere left in t he open below the consoles ( see PHOTO 3) Proper temperature contro l of the operations room was provided by havi ng the w hole room surrounded by w indows w ith easy to cover green curtains t han can be freely open or closed depending on t he temperatu re outside.

Later, much later, w hen post classicism and modernism made the ir inevitab le entry, and radar had to be introdu ced , the y undertook this very carefully by tak ing much time to evaluate the consequences on t he env ironment. They integ rated t he equipment w ith much taste, not want ing to disturb the genera l ambien ce and atmosp here in the place.

Tho mson CSF delivered brand new Sony 2000x2000colour radar. screens during the first radar acceptance tests in 1996. But w hen t he old Signaal radars became unserviceable the Greek tec hnici ans mount ed the new scopes into specially desig ned consoles to fit perfect ly into the old environment . This special design can be seen on PHOTO 4 . I have heard t hat t hey have been tipp ed to be among th e final ists for the much-acclaimed aw ard of the best conso le design So far, it has been extremely difficult to harmoniously integrate the new square radar scopes in a generally 'round' environment, but one can say that t his new art concept of raw natura l materials, (sort of naked tr uth ) is ver y powerfu l indeed and adds to the purity of t he line. It also fits beautifu lly w it h t he rest of t he operat ions room. !n many Cent res arou nd the w or ld toda y big discussions take place arou nd integrating voice communicat ions in a mode rn computeri sed enviro nmen t in the Greek

current system, which I remind you, was designed in the 19S0's, telephone, frequencies and inter-sector communications are independent of each ot her. In fact inter-sector co-ordination is done mainly using human voice, face to face, w ith a back up system using gesture exchanges, some of them very suggestive I Integration of the initial radar surveillance equipment is achieved on the sector by using minimum head movement (as demonstrated on PHOTO 5) The staff wo rking environm ent has not been forgotten. Very modern large personal lockers (for contro llers to store their belongings) have been put at their disposal right behind the consoles (see PHOTO 6) . Some of the doors have difficulty closing today, but museum authorities said thi s was adding to the authenticity and felt it was in line w ith typical Greek hospitality to leave doors open.

Indeed, a wo nderful place to be and no w ond er that the y decided to keep it as a living museum, because yes, everyt hing is still used today to contro l t raffic in 1998.

If yo u go to At hens, do not forget to visit the National Museum, the Agora and the Acropo lis, but reserve some

time to pay a v isit to the ATC liv ing museum at the airport.

But hurr y, rumour has it that an ultra-modern, totally radar equipped new ACC is going to be operationa l soon and that the museum co uld definitel y close, or at least this is what the rumours say.

Th e new Centre, called Pallas, is a brand new radar system built by Thom son wit h all the modern features: Multiradar, strip less environment, Short Term Conflict A lert, Minimum Safe A ltitud e Warning system, automatic hand-offs, OLD! lines, etc w ith a ve ry advanced voice communication system as w ell.

A ll this is ready to become operational but some difficultie s have , until now, prevent ed the tr ansfer of control .

Anyway, most of the Greek control lers still believe in Santa Claus and Father Christma s and all have made a special wish (again) for Christm as 1998 . I leave yo u to w onder w hich one.

Finally, it has to be rememb ered that, despite all the odds w ith the old wo rking environment, the Greek air traffic contro llers have always and still continue to, pro vide a high st andard of safet y, excelling themse lves in w hat they do, especially during the Summer peaks - and all this from a museum!

Photo I: 15 metres of procedural slrip bays.

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Photo 2: Modern telephone exchange system with each telephon e linked to an airport on various islands.

Photo 3: A tyupical Athens ACCsector with ··open Maintenance Panel"", below.

Photo 4: The specially designed consul to house the modern radar screens.

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r 111CONTROLLER

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Famous AircraftNo 2 CANADAIR CL44 of TRANSPORTE AERO RIOPLATENSE, LV-JTN Philippe Domogala, ContributingEditor uring th e Iran-Iraq war, Ayathollah Kohmein i forc es still operated US equipment left over from the time of the Shah and in particular M48 tanks . Due to the relations between th e two countries it was impossible for Iran to get spare parts directly from the USA. Another country in the Region, Israel, also operated M48 tanks and Israel did not want Iraq to win the war.

Therefore, secret ly Israeli firms supplied US spare parts to Iran during the war.

The idea to provide the parts by air started in early 1981, when a Scottis h Broke r named Scott Allan McCafferty was contacted and chartered this Canadair CL44 from the Argentinean company TA. R. The captain for this planned series of flights was Hector Cordero, a well-known playboy and very wea lt hy, who only flew aircraft for fun and excitement.

The aircraft flew from Buenos Aires to Miami to get an engine removed and overhauled. The aircraft the n flew to Amsterdam, where the local police w ho had probab ly been t ipped off that something funny was go ing on, met it. Howeve r the aircraft was fou nd to contain only Mr McCafferty's personal jeep and, after a day of hassle, the CL44 was allowed to depart for Tel Aviv. From Tel Aviv it loaded the spares and transited on an "offic ial" Flight plan to neighbour ing Larnaca in Cyprus From Cyprus the aircraft f iled another flight plan from Larnaca to Teheran , via Turkish airspace. Three successful trips took place on 12, 14 and 17 July ' 81 and a

D

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total of 60 tons of spares were delivered. However, there was still 300 tons of equipment to be flown to Tehran.

The Russians, who were supporti ng Iraq at the t ime, were warned what was going on by one of their spies in Larnaca. On the return leg from Tehran, on the 18 July, the Russians wa ited for the aircraft to approach the Iran/ Turkish bo rder and "hijacked" the VOR frequencies of nearby VAN and ERZ. Th ey used a ve ry powerf ul tran smitter, in order to "lu re" the CL44 into nearby Soviet airspace where they cou ld intercept it.

Thi s worked and the crew, very probably on autop ilot at the time, did not notice the turn . Turkish controllers in Ankara saw the aircraft turning right into Soviet airspace but could not co ntact them on VHF, as the frequency it was on was very probably also jammed in the area of the CL44.

As soon as the CL44 passed over the Soviet Border it was intercepted by two Mig 25s.

Our flamboyant Argentinean captain , realising what was

happening, tried an escape manoeuvre by diving and reversing direction. The Migs however caught it and fired warning shots. The captain of the CL44 then appeared to resign himself to following the Migs. Soon the two aircraft took up position very close to the CL44 to prevent it from escaping again. This probably gave the idea to our Argentinean captain, who decided on a last chance manoeuvre , by suddenly reduc ing speed and veering towards the Migs . He managed to make the propeller of his outer engine crash into the canopy of one of the Migs, which caused the Mig to dive and crash. In the confusion the CL44 tried to manoeuvre and escape again but the second Mig took position and fired its missiles. The CL44 was hit and crashed a few miles from the Turkish Bord er, near Yerevan in Soviet Armenia Sadly, all four persons on board the CL44 perished At first, the Soviets denied the event (recorded on radar from Ankara) Four days later the Soviet Agency Tass issued a statement saying that "an

unidentified plane had entered Soviet airspace, failed to identify itself, made a series of dangerous manoeuvres and had finally collided with a Russian plane, then disintegrated and burned up ."

There were no more attemp ts to fly US spares to Tehran via this route but it is believed the deliveries continued right through the war v ia other means .

Our famous CL44 can be registered as the onl y civil airliner to have actual ly destroyed a Mig. The history of th e aircraft is as follows. It was built by Canadair Ltd, serial number 34, in August 1962 . It was delivered new to the then US Airline SLICK A ir and registered as N605SA. The aircraft later was painted into A IRLIFT colour s after the merger of the two companies.

TAR bough t the aircraft in Apri l 1971 and kept it until its final flight in 198 1. Th e aircraft w as replaced by a Boeing 707 regi ster ed GBOAC w hich was in fact th e very first B707 received by BOAC the airline t hat later became British Airways .

But that is another story

¡ CONTROLLER

New Aircraft Type AR

1999 JANUARY 14 - 16 IFATCA Executive Board M eeting

SOO

M eeting with IFALPA Principle Officers, Mont real Contact: IFATCA Office Manage r Mau ra Estrada Phone: + 1 514 866 7040 +1 51486676 12 Fax: ifatca@sympatico.ca Email: 17

Latest versions of the world's most successful large tuboprop family.

Philippe Domagala, Contributing Editor he ATR family of regional turboprops has evolved over a 15 year period to provide the most cost effective range of short haul. 40 (ATR 42) to 70 (ATR 72) seat aircraft. Five hundred and forty ATR aircraft have been delivered and the latest production versions mix highe r standards of passenger comfort and aircraft performance.

The impro vements provided by new generation occur throughout the aircraft and include : • New style interiors with more baggage space • Lower cabin noise and vibr ation leve ls • 300 kt cruise speed (ATR 42500) • Greater payload range capability • Better airfi eld performance • Lower externa l noise level • Higher specification standard • Maintainability enhancements

Agenda

The main objective to these impro veme nts is to achieve economy of operation and the new performance criteria wi ll affect ATC operations.

As these two aircraft can maintain 250 kt until the ILS, it is intere sting for radar vector ing. The aircraft can also take-off or land in a distance of less than 1100 metres.

THE ATR 42 SURVVEYOR Following t he ATR's world wide success with commercial customers, the aircraft is making a natural expansion int o derivative utilisation such as maritime patrol and coastal survei llance . Called the 'Surveyor', the specification for th is maritime patro l aircraft is driven by the harsh environment in which the aircraft w ill operate. Th e aircraft w ill be rout inely called upon for demanding missions, including the search,

A ir Traffic Control (ATCA) Symposium "Free Flight: Techno logy and Ai rspace Review ", Hyatt Regency Crystal City Hote l, A rlington , V irginia, USA Contact : Carol New master Phone: (703) 522 5717 Fax: (703 ) 527 7251 Email: atca@wo rldnet. att .net

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FEBRUARY 23 EGATS ATC '99 Forum.M aastricht Contact: Forum Co-ordin ator +31 43 3661541 Fax: egats@tip .nl Email: 24-25 ATC '99 Conference . Masstr icht Contact: Lesley Offle y Janes Inform ation Group Phone: +44 181 700 3700 +44 1817003715 Fax: MARCH 12 - 13 IFATCA Exec utiv e Board M eeting, Santiago Cont act: IFATCA Offi ce M anager.

M aura Estrada Phone: +1 5148 66 7040 +151 4 866 7612 Fax: ifatca@sympatico.ca Email:

identification and tracking of sea targets. The « Guardia di Finanza » the Italian Customs Service have placed orders fo r two of the special mission ATR aircraft.

Typically, the Surveyor is

15-19 IFATCA A nnual Conference, Santiago Cont act: IFATCA Offi ce Manage r, Ma ura Estrada Phone: +151 4866 7040 +1 5148 66 7612 Fax: ifatca@sympatico. ca Email: MARCH 20 IFATCA Executive Board M eeting. Santiago Contact: IFATCA Office Manag er, M aura Estrada Phone: +1 514 866 7040 +1 514 8667 612 Fax: Email: ifatca@sy mp atico.ca APRIL 12- 15

ICAO Fourt h Glo bal Flight Safety and Human Factors Symposium Santiago. Ch ile Contact: Capt. Dan Ma urine ICAO Mo ntreal Pho ne: + 1 514 954638 1 Fax: + 1 514 95467 59 Email: dmaurino@i cao.int 14-16

Inte r Ai rport 99 Asia Singapore Exp o Centre Contact: Nadine Smith Pho ne: +44 1707 275641 Fax: +44 1707 275554 JUNE 11 -13

IFATCA Executive Board Meeting, Geneva Contact: IFATCA Office Manager, Ma ura Estrada Phone: + 15 14866 7040 Fax: +1514866 7612 Email: ifatca@sympatico .ca

env ironmen t al prot ect ion. law enforcement and SA R. W ith these new g ene rat io n aircraft.

ATR intro du ces h igh comfort and a better perf o rmance , offset again st a low cost.

capable of prov iding missions

Wh en req ui red, the aircraft

such as exclusive econ omic

w ill be able to operate control

zone protection,

cond itio ns.

AIRCRAFT PERFORMANCE ATR 42 SOO Service ceiling Rate of climb Rate of descent

25000 ft 2000 ft/min 2000 ft/ min until FL 100, 1500 ft / min below Cruise speed 304 kt Climb speed 160 kt Descent speed 250kt Min imum clean speed 150 kt Final approach speed 110 kt

ATR 72 SOO Service ceiling Rate of climb Rate of descent

25000 ft 1800 ft/ min 2000 ft/ min unt il FL 100, 1500 ft / min below Cruise speed 280 kt Climb speed 170 kt Descent speed 250 kt M inimum clean speed 130 kt Final approach speed 110 kt

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Charlie's Column CO NTEST FOR THE BEST TAKE OFF IN 1998 The pri ze was w on by Captain XXX of Redmond Airlin es (no connect ion w it h our EVP Finance) in Portland , Oregon last Ma rch , w ho failed to start th e righ t engine of his twinj et SN601 Corv ett e but decided to try to tak e off on one engine only. The aircraft apparently lifted off for tw o or three met ers, then f ell back on the runway and crashed at the end. All four occupan t s escaped with on ly ligh t injuries. After inv estigat ion it appeared that the Captai n unsuccessfully t ried eigh t t imes to start the right engi ne , but eventual ly de cided to t ry to take off. He believe d he would be able to start the engine during th e t ake- off ro ll using the aircraft speed ( For informa tion, to start a jet engine you need a speed in excess of 200 Kts - almost twice t he normal take off speed). It also appeared that the co-pilot was not jet qualified (only a PPL lice nce) but he was the only one on board that objected to the procedure. Staff on the grou nd reported that the Corvette was exceptionally quiet and was very slow during its atte mpted take off. You bet l

OOPS Las September a KLM MD11 on a flight from Curacao to Amsterdam, was invo lved in an airmiss w ith another MD11 from Sw issair fl ying oppo site direction. The KLM pilot was understandably quiet . Some moments later he had another airmiss w ith an opposite direction British Airwa ys B767 .

Th is time our KLM Captain gets really upset and make this know n to ATC: "What are you doing dow n there ? - Is someone watch ing or w hat?" A little later, w hen entering radar airspace, it turned out that our KLM MD11 w as 76nm off track, (although he had been reporting 'on track' on the radio for the last 6 hours or so .) Apparentl y, the KLM pi lot mad e an error in programming his FMS on departure 1 Remember! Always t hink tw ice before starting to blame yo ur neighbour!

BICYCLES I always like to refer to the slow movin g t urbo-prop s tr ansit ing my airsp ace as "Bicycles" During periods of low traff ic, w hich becom es rarer and rarer, passing traffic infor mati on mentioning : "Traffic 2 o'clock, bicycle moving fro m righ t to left " alw ays ge nerat es some interesting

comments . However I read here that, last June, the UK pol ice passed on a complaint to the UK CAA that a metal object fell from the sky in St Albans and made a ho le in a plastic garden table. After investigation, it was discovered that the piece of metal was identified as a quick release mechanism for a bicycle wheel. I told you all along there were real bicycles up there .

OV ERHEARD ON THE PUBLIC ADDRESS Follow ing a Simon and Garfunkel song on the aircraft public address system a flight attendant was heard to say, "Ladies and gentlemen, there might be fifty ways to leave your lover but there are only nine ways to leave thi s 757, so you'd better listen ...

CHARLIE's PHILOSOPHICAL QUESTIONS Why w hen two aircraft nearly hit each oth er do newspap ers call it a "near miss"7 It should be call in fact a "near hit" .

Wh y do aircraft light switches have ON and OFF written beside them7 If it is on, you can see it is on . If it is off, it is dark and you cannot read it anyway.

Wh y is that, according to the Police, that 95% all car accidents

occur within five miles of home?

If I left my car five mi les from home every day and walked the rest, wou ld I be assured of not having an accident? If I moved house f ive miles away from where I live now, and do not tell the po lice, would this have the same effec t 7

VARIOUS WAYS TO MANAGE AIR TRAFFIC CONTROLLERS (1) There are many schoo ls of thought on how new managers should tac kle ATC Staff. Here are a few examples on the most common forms of ATC Management : MANAGEMENT BY HELICOPTER Always look around from above, from time to t ime descend to the ground, make a lot of noise and move around a lot of dust, then go back up again .

ROBINSON CRUSOE MANAGEMENT STYLE All w aiting for Friday.

MUSHROOM - STYLE MANAGEMENT Keep the w or kers in the dark, feed them manure (* ) and wh en you notice on e head coming out , cut it off immediate ly. (* ) other forms of fertilisers can be used I

Le ters to the Editor From: JAMES R. (JIM) BANKS ATCA, VICE PRESIDENT INTERNATIONAL AFFA IRS ARLINGTON, V IRGINA 22201 Reference The MARS JRM story in The Contro ller 3/98 The U.S Navy JRM flying boat ("The Germ"), operated between the Naval Air Station, Alameda, CA and John Rogers 'seaport' (Keehee Lagoon), Honolulu during the approximately 6 years I was stationed w ith the (old) 9th CAA Region (1951-57) I work ed (communicated with) these

32

aircraft using CW (morse code) during my stint at KVM , (CAA 's Oversears/Foreign Communitions Station OFACS) copying position reports w hich were relayed to ATC. The aircraft and crews were t he epitome of oceanic operations; t he navigators wer e always "on the money" and the flight radio operators were to p-notch.

Subsequent to my transition into the Hono lulu A ir Route Traff ic Control Centre, we used the JRM as a relay source and model for confirming flig ht condit ions and other aircraft position reports

across the 2046 nautical miles of the Pacific between Honolulu and Alameda. It was a good operation and the article brings back fond memories.

From: ERIK LITILE c/o 4981-12A HWY 7 EAST SUITE #208,MAR KHAM, ON L3R 1N1, CANA DA I send this small article on the very human factor of fatigu e management on behalf of the cont rollers with w hom I wo rk. It has been a small seed th at germinated as a result of my

experience and contributions to a symposium on fatigue in t ransportat ion held in Washington . I t rust that you w ill give it du e consideration for the "The Controlle r" As yo u know I have been involved w ith health and lifestyle concern s of ATC for some tim e now; gosh it's over twe nty yearsI From w ellness programs to cumulative stre ss to CISM and now fatigu e management.

As always I invite commentary and discussion with the members, for that is one way in w hich the industry and its

,, CONTROLLER

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services evolve. For the past ten years, in parallel with my input in the CISM arena I have been wo rking towards defining and designing countermeasure programs, specific to fatigue management In profile, most of my effort s in this arena are directed towards the contro llers of the Ontario region, while I am part of the implementation and design team w ith Nav Canada, and have presented an overview of fatigue management to the Americas committee (Technical) in Trinidad (1997) Mor e importantl y, t his is an

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area that needs ongoing discussion and feedback so that the human factor is not buried in successive waves of technology, economics and politics.

NAVCOH Consultant Ontario region If members wish to contact me through the electronic world the y can do so at: littl ee@navcanada.ca

MORE THAN JUST A LITTLE TIRED A commenta ry on the nature of fatigue in ATC

Erik Little The scenario is simple enough . A controller is asked to wo rk a double shift; an evening to a midnight, because of staffing problem s He reluctantly accepts. The local manager might have observed that the controller was somewhat irritable regarding t he prospect , but that might be considered normal during these times (everyone is a bit on edge ... ) The controller· might recall that they were tired and frustrated , and agreed to work only because there seemed to be no

other person availab le . The controller might also recall that recently t hey had had some difficulties remaining focused a wandering mind that wasn't a prob lem but d id add to the frustrat ions by making routine tasks a chore .

The midnight wou ld progress as expected . Traffic dies off , bui lding noise subside s and the contro ller become s more of a monitor w ith predictab le tasks to complete . The "dead zone " in the middle of the shift is harde r than on most 'midnigh t's', but that too is expected . Everything proceed s

33

Letters to the Editor as expected. Until the last hour of the shift. By this time the controller has been awake for more than 20 hours . As the data for th e day starts to accumulate and the traffi c load picks up, the controller loses the picture.

Control gives way to confusion and then chaos w ith in seconds.

He cannot see two targets heading for the same point on the screen. Watching but simply cannot see.

A critical incide nt. Conflict. A close one. An accident avoided by ..?

By the tim e the day shift arrives and th e incident paperwork has been completed the controller has been awak e fo r more than 25 hours . He drives home. Alon e.

An unusual circumstance? No. An isolated incident? No. Log ic errors, lapses and micro sleeps are w ell docume nte d occurrences in any service indust ry working shifts, particu larly as computers take over many of the repetit iv e tasks Double shifts, quick changes, extended shifts and overtime are becom ing a fact of life during t hese economic t imes, as increasing demands fr om a 24 hour global aviation ind ustry outstrip the ability to train and retain the control staff: Despite the fact that more t han 30% of the pop ulation may be w orking shifts or extended hours, t he beliefs and att it ud es behind governmental directives, corporate decisions and societal lifesty les are anchored in a day shift mode . The impl ications are far-r eaching. Consider : • The local manager, acting on behalf of t he com pany, consider s staffing requ irement s first and not the context of t he request (perhaps thi s is t he fourt h doubl e this month fo r the cont roller, rendering him a virtual drunk with respect to responsible decision making) [be lief = a shift is just another shift] • The controller may not realize that fatigu e introduc es an inability to assess need s or rights, and accepts the shift because its expected and

because there is pressure to decide w ith a manager standing in front of them. [belief= training and experience w ill maintain an acceptable level of professional effectiveness] • Wh ile antic ipatory errors, selection errors, lapses and micro sleeps are a common phenomenon in the midnight environ, the controller may have no idea that they are happening until a serious t hreat jolts the controller's alertness chemist ry. [belief= "If I'm awake, I'm aware"] • Most shift schedules are designed with some opportunity for recovery from the effects of disruption or acute sleep loss. New systems consider recovery time between shifts. A thirty year old system may not consider or adjust for the extra traffic load and shift increases, leav ing the controller in perpetual sleep debt that accumulat es like a bad investment. [belief= a good night's sleep wi ll restore alert ness] • In a now dated survey of Canadian controllers a sign) fi cant percentage indicated t hat they had fallen asleep wh ile driv ing home after a midn ight shift No reported deaths Tod ay the orga nization may be sharing accountabilit y in the case of acute sleep loss, related accidents and not be aware of it. [be lief= "I can force myself to stay awake for a short period of time "] [belief= the co ntrol ler is total ly responsible for t heir we ll-being once the y leave the buildin g. ] Al l of t he noted be liefs that contr ibute to the decision pro cess are false They all influen ce a sense of "normalit y" while und ermining profes sional capab ility As each falsehood becomes accepted as a norm al w orking behaviour, safety becomes more dependent on luck and less on professiona l style . A s ever y contro ller comes to know ; th e safety recor d is not the same as a safe operat ion .

In an ideal ATC world staffing would remain synchronous with industry needs and the shift schedule would allow for recovery from circadian disruptions and sleep debt incurred during shift rotations.

But we all know that staffing has an ebb and flow over time, dictated by factors outside of actualneed. Fatigue will always be a part of the aviation industry. Acceptab le in the short-term, fatigue becomes dangerous over extended time because of the deterioration of the balance between safety and effecti veness. Fatigue is powerful enough to undermine training, experience, motivation and capability while feeling "normal".

At some point safety becomes reactive; an after-the-fact struggle. The future of fatigue management includes computerized scheduling programs, individual monitors and countermeasures, screening

systems and bargained work limits. These are all viable elements in the management of fatigue, but I predict that the real challenges in ATC will be human and not technological.

In my opinion there are two course s of action that w ill change the attitudes and decision s that drive fatigue management. In one scenario, education and directives change the mind-set at all levels so that fatigue management becomes a natural part of ATC culture and structures, perhaps in parallel with the growing societal acceptance of the shift working world.

The other scenario involves waiting, either blindly or politically, for a media-scale disaster that highlights fatigue.

In both cases t he issue of fatigue management will be addressed, and changes will occur. The choice between whether those changes are imposed or evolve may well be yours.

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34

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