17 minute read
Accident Analysis Who’s in control?
Safety Accident Analysis Who’s in control?
While we all love to share our joy of flying with friends and colleagues, Steve Ayres examines why it’s worth looking at some of the possible consequences of handing over those precious flight controls – and why it’s important to get the cockpit ‘relationships’ right
Advertisement
For all pilots making a bit of a ‘thing’ about ensuring they always know who has control of the aircraft at any one time, it IS really important. It’s obviously crucial in the instructional environment, but then it is usually quite obvious who should be taking control if things start to go wrong. It is the instructor, of course! But, is it always? And what if the aircraft owner is in the ‘command’ seat but his passenger in the other seat is much more experienced, more familiar or just ‘clear as day’ more capable! Add to this the stress of a serious emergency and the scene is set for some tricky decision making – even before the need for some nifty aircraft handling by the one left ‘in control’.
Accident 1
The Beechcraft B200 aircraft, equipped to perform medical evacuation flights, was conducting an instrument flight rules positioning flight, with two flight crew members and two flight nurses on board. While the aircraft was cruising at flight level 250, the flight crew declared an emergency due to a fuel issue, which the crew then realised meant they would not make it to the destination. It was at that moment that the First Officer (FO) remembered that he had forgotten to have the aircraft refuelled.
The flight crew were ‘startled’ by the fuel exhaustion situation, and their management of the emergency subsequently deteriorated as they were faced with a higher and unexpected workload owing to the impending fuel exhaustion and imminent power loss of one, and eventually, both engines.
When the left engine lost power, the flight crew followed the procedure to shut down the engine. However, the left propeller continued to windmill at speeds between 1,300 and 2,000rpm.
It is likely that the propeller control lever had not been moved completely into the feather position. The FO had earlier programmed the FMS to display a track to the diversion airfield on the captain’s FMS and he instructed the captain to turn right and fly the new track. However, only when the FO moved the heading bug on the FMS display did the captain turn the aircraft, some two minutes after his initial call. Still feeling the effects of the startled response to the fuel emergency, the captain quickly became task-saturated.
The drag produced by the windmilling propeller explains the decaying airspeed and the difficulty the captain was experiencing controlling the aircraft. Although the captain was attempting to descend to intercept an acceptable approach angle, the windmilling propeller likely contributed to a rate of descent that was higher than expected, and at times approached 6,000fpm. Observing that the captain was encountering difficulty maintaining airspeed and controlling the descent rate, the FO took control.
When the aircraft was at 2,800ft above sea level (asl), the left propeller stopped rotating, indicating that the blades had moved to the feather angle.
The right engine then lost power due to fuel exhaustion when the aircraft was one nm from the threshold. From that position, a successful forced landing on the intended runway was no longer possible and, as a result, the aircraft touched down on the ice surface of Stephens Lake, short of the runway. The aircraft was severely damaged but there were no injuries and the occupants exited the aircraft.
The FO was a company line ‘indoctrination captain’, and on the occurrence flight he occupied the right-hand seat from where he was to perform the duties of a FO and provide line indoctrination training to the captain. The FO believed that the captain was the PIC, although in accordance with company policy it should have been the FO, as he was the one giving training to the captain.
Accident 2
The flight of the Cessna 172 was part of a three-plane, multi-day trip between Germany and France. The pilot (in the left seat) and the passenger, owner of the aircraft (in the right seat), took off from Dijon around noon for a flight to Tours. The accident pilot explained that he had met the owner of the aeroplane a few months before but that they had never flown together prior to this trip. As this three-day outing took place in several stages, they alternated in the role of captain. The day before the accident, the pilot flew one of the legs in Germany as a captain. On the day of the accident, he captained the Dijon-Tours leg from the left seat, while the owner provided radio communications in the right seat.
On final for Runway 20 at Tours Aerodrome, the pilot said he had stabilised the speed at 70kt with the flaps configured in the landing position at 30°. After the flare and despite the reduced power, he had the impression that the aircraft was flying over the runway without touching the ground, as if it were floating on a cushion of warm air. For him, this effect was caused by the high air temperature just above the paved runway heated by the sun. He then decided to abort the landing and applied full power. At the same time, the passenger told him ‘go-around’. He estimated the speed at about 65kt and the available runway length at 1,500m.
The pilot’s intention then was to gain speed over the runway before gradually retracting the flaps. Seconds after the go-around, he perceived a change in nose-up attitude and pushed the yoke forward to maintain a level accelerating attitude. As that effort increased, he perceived a left turn and realised he was no longer above the runway. The pilot noticed that the passenger was also holding on to the controls. Startled, he stopped pushing the yoke and controlling the rudder pedals, believing that the passenger, the owner of the aircraft and more experienced than him, wanted to fly the manoeuvre himself. He thought that the owner might have wanted to make a quick left turn into the airfield circuit. He then passively accompanied the movement of the yoke without opposing it.
The pilot stated that when he noticed the speed was slowing he yelled at the owner to stop pulling as they were losing speed, but got no reaction from him. The aeroplane suddenly rolled over to the left and collided with the ground. With both occupants unharmed, they evacuated the aircraft.
He clarified that during the briefing given before the start of the trip, he and the owner agreed that if the owner was to take back control of the aircraft, then he should announce it using phraseology defined in advance. He did not hear this announcement during the accident flight.
Testimonies show that the situation was confused in the cockpit and that the two people each assumed the other was in control, with neither of them actually piloting the aircraft. The go-around procedure was therefore partially applied with only the throttle properly actioned. Control of the flight path, management of the engine effects and flap retraction were not.
Accident 3
Two experienced pilots began a flight in a two-seat glider near Briançon. The front seat pilot considered the other pilot to be the pilot-in-command because he had an instructor’s qualification and knew the area better than himself. The rear-seat pilot placed the flight in the context of a ‘mutual flight’, taking on the role of captain but leaving control and initiative to the other pilot. The two pilots did not, however, discuss the assignment of roles and functions before the flight.
At some point, the front seat pilot continued the flight in conditions disapproved of by the rear seat pilot, but he did not express this clearly and, although stressed, he left the controls and initiative with the front seat pilot.
When the front seat pilot could not find any lift, he decided to end the flight and land in the Rosier area. He prepared for the landing by commenting on his actions aloud. Thinking he was in difficulty, the rear-seat pilot took control and tried unsuccessfully to gain altitude, so he too resolved to land. He flew a downwind leg that was too close – and consequently was too high – on final.
Seeing that they had not descended sufficiently, he extended the spoilers fully, selected land flap and asked the front seat pilot to deploy the brake-chute. Immobilised since the rear seat pilot had taken control and after a few seconds hesitation, he pushed the release lever through the gate deploying, and then accidentally, jettisoning the brake-chute. The glider flew over the entire length of the field and in an attempt to avoid a tree line, the two pilots simultaneously retracted the spoilers and applied up elevator. The glider struck a tree and came to rest on its back in a river, submerging the occupants who were able to evacuate.
Ayres’ Analysis
Thankfully, it was mostly pride and airframes that were hurt in these accidents – but it could have been very different. And, although the relationships between crew members were not the principal cause, in each accident they certainly contributed. In the case of the Beech 200, the FO in his role as training pilot should have been the one in command and, given his greater experience, would most likely have been best placed to take decisions and to pilot the aircraft. As it was, confusion in the roles may well have compromised their ability to action the emergency drills correctly and then to reach the nearest airfield safely.
In the case of the Cessna 172, the skills of the pilot flying were almost unknown to the owner-pilot in the right-hand seat and when things got a bit fraught on landing there was a lot of confusion in the cockpit, ending up with no one piloting the go-around. And this was despite the control handover procedure being discussed previously! In the final example, there was no defined scope for the flight and the precise roles of each of the two pilots was not covered.
The flight took place based on presumptions around status (instructor/student) and experience (local knowledge/cross-country flights). This clearly had an impact on the ability of the two pilots to work effectively together. When things started to go wrong communication between the pilots suffered, they alternately adopted a passive attitude, which ultimately impeded their ability to carry out a safe landing.
Guarding against these kinds of accidents can be difficult and as the C172 accident demonstrates, even a pre-flight brief won’t necessarily keep us safe.
However, spending time discussing the flight profile and the roles each crew member is going to play during that flight is clearly important. Also, agree on who is going to take control if things go wrong and the role the non-flying pilot is to play (monitor speed, nav, radio etc). And finally, keep flying the aeroplane unless someone shouts very loudly in your ear: ‘I have control!’
Safety Accident Reports
When checking is key…
Steve Ayres summarises and comments on accident reports from around the world and looks at a very handy pilot ‘breakout device’ and survival knife…
No greens, no horn
Rockwell Commander 114 G-BFXS Little Snoring Airfield, Norfolk Injuries: None
The pilot was planning to complete two landings at Little Snoring Airfield, before flying to Old Buckenham Airfield to complete the required three landings in 90 days, prior to flying with passengers.
He took off from Runway 07 and completed the first circuit without incident. As he was flying downwind in the second circuit another pilot asked him to extend his circuit to allow them to take off. He extended downwind then made his approach to land.
He thought he had completed his normal downwind checks, which would normally include extending the landing gear, and on final approach he made his normal ‘red, blue, greens’ landing checks.
However, on landing, the propeller and fuselage struck the runway and he realised the landing gear was not selected down. The landing gear warning horn did not sound. The pilot was uninjured and able to exit the aircraft unaided.
The pilot had not flown for several months and he thinks that the lack of currency, combined with the distraction of extending the circuit, led him to forget to extend the landing gear. He believes that on final approach he glanced inside and saw the GPS green light and mistook it for the landing gear green lights.
The landing gear warning horn did not sound because the pilot had selected only partial flap, intending to complete a touch-and-go. The landing gear warning horn sounds when the landing gear is not down and, either the flaps are extended beyond 25°, or when the throttle is retarded below a position corresponding to a manifold pressure of approximately 14in. Comment Given the long lay-off from flying many of us have experienced, this sort of accident is perhaps unsurprising, but it occurred despite Rockwell’s designers doing their best to warn the pilot.
Unfortunately, a decision not to use landing flap and a possible late reduction in power below 14in manifold pressure, denied the pilot any chance of that final warning.
Forgetting the gear is the stuff of nightmares (for me anyway), but given a broad lack of currency it might be a good time to reflect on whether we are making full and proper use of all our safety systems. Plus a timely reminder of the need for that ‘last check’.
Fatal distraction
Cessna 150M N6AF Bainbridge Island, WA Injuries: One fatal, one serious
The private pilot and passenger departed on a pleasure flight over the water, and radar data showed that the aeroplane was at an altitude about 700ft mean sea level (msl). The passenger stated that she was concerned about how low the aeroplane was flying, but the pilot reassured her that they were fine and able to fly safely 200ft above the water. The pilot then looked down at his tablet, which he was using for navigation, and the passenger saw him push the flight control yoke forward. The aeroplane descended and subsequently impacted the water and nosed over. The passenger was able to egress on her own as the aeroplane began to sink. However, the pilot appeared unconscious and did not exit the aeroplane. Neither the wreckage nor the pilot’s remains were recovered. Comment There’s a hint of bravado in the pilot’s comment to his passenger about being ‘able to fly safely over water at 200ft’ and, while it may be true, it cannot be accomplished when distracted. We all know how invaluable some form of electronic mapping/navigation has become, but make sure the device is mounted to promote lookout and not to detract from it. And when using it, make it part of your scan rather than let it become something on which to fixate.
Dire detonation
Zenair Zenith STOL CH750 N328SK Napa, CA Injuries: None
The pilot/owner was conducting a flight in the experimental amateurbuilt aeroplane with a pilot-rated passenger, who was a potential buyer. The pilot reported that they flew in the local area for about 20 minutes, and then smoke entered the cockpit. The pilot declared an emergency and headed toward the departure airport. Within one to two minutes, the engine lost all oil pressure and then lost total power.
The pilot initially attempted to glide to the airport, but because it was too far away, decided to land on a road on top of a nearby dam. The
Safety Accident Reports
aeroplane touched down normally, but due to wind the left wingtip struck the ground. The aeroplane spun, veered off the dam, and sustained substantial damage to the wing and fuselage.
The engine exhibited some impact-related damage, but no external evidence of non impactrelated damage. The engine was, however, devoid of lubricating oil, and significant oil residue was observed on the exhaust and the lower fuselage.
Post-accident examination indicated that the source of the oil was via the starter ring gear drive seal, located just above the exhaust All four pistons displayed evidence of significant erosion damage consistent with detonation. The damage was consistent with the use of fuel with octane rating(s) significantly below that required for the engine.
At least one piston was eroded to the point that it allowed cylinder combustion gasses to enter and pressurise the engine crankcase, which would have forced the engine oil past the starter ring gear drive seal and out of the engine. Comment There can be no substitute for regular and proper maintenance. Had the pilot done so, perhaps the detonation-caused internal engine damage would have been detected before it got to the point where combustion gasses were able to force oil out through the seal in the crankcase. That said, running the engine on the correct octane fuel would have been the best preventative measure of all.
Phantom partial power
VH-YPQ Diamond DA40 NG Port Macquarie Airport, NSW Injuries: Two serious
It was the student’s first time conducting night circuits so, once lined up on the runway, the instructor took the aircraft controls for the take-off. As the aircraft climbed, the instructor heard, and felt, the engine and propeller surging. Propeller speed and engine power fluctuations occurred from about 200ft and increased in amplitude as the aircraft climbed to about 400ft.
Recorded data showed that the engine was, nonetheless, producing full power despite the fluctuations.
The instructor interpreted the fluctuations as a partial engine power loss and commenced a left turn, aiming to return and land on the runway in the opposite direction to the take-off.
The instructor had considered landing straight ahead but assessed that there was power available to turn and that they would be unable to see and avoid trees or to be sure to land in a suitable clearing ahead.
In the 10 seconds that the instructor was assessing and making decisions about a perceived partial power loss, the airspeed reduced from 75kt to 69kt due to the aircraft’s nose-up pitch attitude.
Then, at the same time as commencing the turn back towards the runway, the instructor reduced engine power to 30 per cent, while maintaining a nose-up attitude, and the airspeed reduced rapidly.
During the turn the aircraft aerodynamically stalled, resulting in a loss of control. Although the aircraft pitched down and the instructor subsequently increased the power, control was not regained. The aircraft descended and collided with trees. The student and instructor were seriously injured, and the aircraft destroyed.
Propeller speed fluctuations had occurred in other aircraft, and had either resolved without pilot input or by moving the power lever. Comment As it transpired the instructor failed to appreciate that he had sufficient power to fly the aircraft normally and that there was no need to plan for an emergency night landing at all.
The distraction from pursuing his plan to land immediately unfortunately then led to loss of control when a few additional seconds of reflection may just have changed the course of action.
Safety kit
Pilot Survival knife
£28.83 | https://bit.ly/2YeWO8J
Having something to hand when it comes to an emergency egress might just make the difference between success and failure. This device by Flight Outfitters would easily stow into a secure pocket or locker and still be readily available.
In addition to the two-in-one blade design, there is a built-in LED flashlight on the top of the knife. The handle also features a seatbelt cutter, a glass breaker
tool, and a clip to secure the knife on a belt or bag. All of these features are neatly contained within the rugged yet attractive grey and black handle.
Breaking through Perspex is never easy, but this device would make doing so much more likely than using just your clenched fist!
Available in the US or through LAS Aerospace (just search for product code 13-20665).
