17 minute read
Accident Analysis Risky intent?
Safety Accident Analysis Risky intent?
While we all applaud a light touch to the regs that govern the way we go about our flying, sometimes that isn’t enough to protect us from ourselves. Steve Ayres takes a look…
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Many pilots are quick to lambast our various certifying organisations as being overly proscriptive, bureaucratic and even, in some instances, ‘killjoys’.
Many pilots fly homebuilt aircraft considered ‘experimental’, and surely the principal is in the title – ‘... it’s experimental guys, which means we can give it a go’.
I must confess to thinking like this at times in my own flying career – and during a recent aircraft build – but it is for the better that we have that independent oversight.
As these two accidents show, when left to our own devices, it might be good to have someone point a finger and ask ‘are you sure about that?’ Accident 1 An experimental amateur-built Jet Eze aeroplane was destroyed after an inflight break-up and a subsequent impact with terrain near Covington Municipal Airport, Tennessee.
The owner, an airline transport pilot, was fatally injured. According to a witness, who routinely observed the accident aeroplane’s flights and was familiar with the aeroplane’s design, reported that the aeroplane departed and climbed to an altitude of about 1,000ft before starting a 270° descending right turn to overfly the airfield at about 200ft, with an estimated speed of 200kt to 210kt.
Shortly after the aeroplane crossed the runway, he saw the left wing and winglet ‘oscillate’ about five times, and that the left wing then ‘exploded’. This witness subsequently observed pieces of the aeroplane falling, abruptly pitching up about 90°, the right wing separating from the fuselage – and then the aeroplane descending into a field.
He provided an additional statement about three months after the accident, indicating that the aeroplane was travelling ‘at least 200kt, it could have been 230kt’, just before the left wing failure.
The pilot held an airline transport pilot certificate with an aeroplane multi-engine land rating, plus a commercial pilot certificate with aeroplane single-engine land and lighter-than-air balloon ratings.
He also held a flight instructor certificate for aeroplane single- and multi-engine land, plus type ratings for the Airbus A320, Jetstream BA-3100, Embraer EMB-120, and Saab SF-340. He also had a repairman experimental aircraft builder certificate for the accident aeroplane as well as for the DR-107 experimental amateur-built aeroplane.
According to FAA airworthiness records as well as publicly available information, the aeroplane was a two-seat, original design, canard-style aeroplane manufactured by the pilot.
It was powered by a modified GE-T58-8B turbine engine, which was originally designed for a military helicopter. The aeroplane received a special airworthiness certificate on 30June 2014. Earlier in the year, the accident pilot described the design, manufacture and operation of the accident aeroplane in a narrated webinar entitled So, You Want to Build a Jet?, which was hosted by the Experimental Aircraft Association.
During the webinar, the pilot reported that the accident aeroplane had a Vne (never exceed airspeed) of 250kt indicated airspeed (KIAS), or 310kt true airspeed, and stated, “Have I been past that (airspeed)? Yeah, it was exciting, and I won’t tell you how far I went past it.”
He explained that the aeroplane was ‘airframe limited’ because the jet engine could propel the wings faster to loads that they could not tolerate.
He also reported that the aeroplane’s first flight was in 2017, although the aeroplane had received its FAA special airworthiness certificate in June 2014.
Examination of portions from the internal left wing structure was performed by the NTSB Materials Laboratory in Washington, DC. This examination showed that the upper wing surfaces and the upper spar cap sections had areas that were consistent with a resin-starved or dry laminate.
These areas were also consistent with an adhesive disbond between the respective faying surfaces. This adhesive disbond was consistent with a lack of impregnation and interaction of the resin into and with the fibreglass fabric, resulting in a lack of strong adhesion between the wing skin and the spar cap. These issues were consistent with a fabrication problem during manufacturing of the layup rather than wear over time or an environmental degradation failure. Additional information: The first witness reported that about two months after the accident aeroplane’s first flight in 2017, a flutter event occurred with its left wing. The witness stated that he saw the flutter event on a video that the accident pilot had shown him. The video camera appeared to be mounted on the left wing, and the video of the flutter event showed the left winglet moving forward and aft, in a back and forth motion, about four inches and about one revolution per second. The witness
thought that the airspeed during the flutter event was 232 KIAS. He reported that he was unaware of any structural repairs or modifications to the aircraft after that flutter event. Accident 2 The Jodel D117A was being operated on a Permit to Fly and had no modifications adapting it for the disability of the pilot, a left forearm amputee. When flying the aircraft, the pilot used his right hand to control the throttle. To operate the ailerons and elevator, a rose jointed adapter which was secured to the prosthesis on his left arm, was attached by an interference fit to the control column. All other controls were conventional.
The pilot was flying circuits with a wind slightly from the left and steady at 10kt. On the fourth circuit, the pilot established the aircraft on the final approach and trimmed for 50 KIAS.
At about five feet above the ground, while the pilot was flaring the aircraft, the prosthetic adapter became disconnected from the control column.
The aircraft reverted to its trimmed shallow nose-down attitude and subsequently struck the ground. The landing gear dug into the ground and folded back under the wings, and the nose of the aircraft pitched down further, damaging the lower engine cowl and the propeller, and shockloading the engine. The pilot was uninjured and, after making the aircraft safe, exited without difficulty using the left cockpit door.
The pilot was a doctor with extensive experience in the management and prosthetic rehabilitation of people with acquired and congenital limb loss. He had held a flying licence for almost nine years and had flown the Jodel for almost five, of which he had flown more than two years and more than 230 hours using the prosthetic adapter.
The reissue of the LAPL medical certificate required the pilot to undergo a medical examination, and a medical flight test (MFT). The medical examination, conducted by an Aeromedical Examiner (AME), focused on the medical aspects of the amputation, and included an assessment of the prosthesis and its fitting to the limb.
The MFT was carried out by a chief flying instructor (CFI) and included discussions about the possibility of disconnection of the adapter and actions to mitigate the
consequence of any such occurrence.
Typically, this would involve taking hold of the control column with the right hand to enable the pilot to retain control of the aircraft, while he reattached the adapter before resuming normal control. During the MFT the pilot demonstrated this and the CFI noted the prosthetic adapter was ‘solid, well made with no play’. Subsequently, the pilot practised regaining control while flying following a disconnection of the adapter from the prosthetic on a regular basis. Conclusion: The aircraft landed heavily when the prosthetic adapter detached from the control column late in the approach and the pilot was unable to regain control before touchdown. The pilot met the requirements for medical fitness to fly, but there was no engineering rating by a suitably qualified individual of the interface between the prosthesis and the aircraft controls.
The lack of a secondary device securing the prosthetic adapter to the control column meant its security was solely reliant upon the interference fit.
The CAA is taking action to ensure there is proper engineering oversight under similar circumstances.
Ayres’ Analysis
When hearing about some accidents it is difficult not to think that, at best, it was a bit of Murphy’s Law – ‘anything that can go wrong will go wrong’ – and at worst, ‘an accident waiting to happen’. And this despite all those involved with aviation working tirelessly to ensure that inspection regimes, design authorities and legislation operate to give us the freedoms we as aviators crave while keeping us safe.
Regrettably, as individuals we don’t always play the most constructive role and no amount of legislation, rules and oversight would be enough. True, when things go wrong they can do so without warning – and quickly. But not always. Often there is a bit of a heads-up, a certain ‘je ne sais quoi’, which gets our antennae quivering and has us delving under the bonnet or at least muttering questions behind a raised hand to a trusted colleague. And yet things still fall through the cracks.
In the case of the Jet Eze, the pilot openly admitted to exceeding Vne and experiencing flutter. Something that would set alarm bells ringing with most of us and leave us questioning the cause and the potential damage, all the while thankful that we had survived the flight. Despite the pilot holding numerous flying and engineering qualifications it was not enough to keep him safe.
And even when we get things mostly right, as did the Jodel pilot in producing a cleverly designed prosthetic adapter, no one spotted the weak link in the chain.
Even though he was able to demonstrate inflight that he could relocate a disconnected adapter, to be able to do so at a critical phase of flight was always going to be problematic. In this instance, new CAA legislation should prevent a repeat accident by requiring some proper engineering oversight.
While in the UK we might not always appreciate that level of regulation and bemoan how sometimes it stifles experimentation and innovation in aviation, it does protect us from some of our greatest excesses and for the vast majority, at least, keep us safe.
However, it will never pick up everything, and if something unusual happens or we find ourselves operating on the edges of what might be deemed ‘normal practice’, it might be worth taking a step back, reflecting a while and seeking a second opinion. Which, of course, we will do, listen to and take action.
Safety Accident Reports Make time to check
Steve Ayres summarises and comments on accident reports from around the world and looks at a very neat and lightweight ‘bothy bag’ that could just save the day…
That sinking sound
Icon A5 N838BA Duluth, MN Injuries: None
An ICON A5 amphibian aeroplane was damaged when it was involved in an accident near the Sky Harbor Airport (DYT), Duluth, Minnesota.
According to the pilot, he taxied downwind on the water for take-off. When facing into the wind, he applied full power and about five seconds later, heard a ‘loud bang’. He shut down the engine, climbed out, looked back, and saw that all three propeller blades were missing. At this point the aeroplane started to sink. He and his passenger donned life jackets and evacuated the aircraft.
Substantial damage was noted to the aeroplane’s fuselage, including holes in the hull.
Several days later, the pilot recalled that before he taxied out the aircraft had been washed. He had placed a portable speaker on the top of the aeroplane to listen to some music. He did not recall putting the speaker away before departure. He added, ‘that the speaker must have rolled over the engine compartment and into the propellers’. Comment We’ve all done it, put something on the wing while chewing the breeze or while working on the airframe, but this accident reminds us how risky that can be, particularly where pusher props are concerned.
I will leave our amphibian pilots to explain how they do their walk rounds, but there is no doubt how vital a part they play in keeping safe. Full and free?
Van’s RV-8 N836JC Mandan, ND Injuries: One fatal
A Van’s RV-8 was destroyed when it was involved in an accident near Mandan, North Dakota, in which the pilot sustained fatal injuries.
According to initial information from the Federal Aviation Administration (FAA), a witness observed the aeroplane on the ramp prior to the flight and advised the pilot that the rear seat belt was securing the rear control stick. The pilot subsequently departed in the aircraft. The take-off was a threepoint one and the aeroplane then had a steep climb. The aeroplane descended, impacted terrain, and a ground fire occurred. Comment The probable cause is a reminder to always do that full and free check. For tandem cockpit aircraft in particular, it is a further reminder that securing the rear stick for whatever reason is a potential recipe for disaster.
Galloping go-around
Cessna 182RG M-GOLF Mount Rule, IoM Injuries: None
The pilot and a passenger, also a pilot, were flying from Ronaldsway Airport to a private airstrip at Mount Rule on the Isle of Man. The pilot had not landed at the airstrip before, but the passenger had landed there many times, but not in M-GOLF.
The take-off appeared normal and there were no technical issues noted with the aircraft while en route.
Upon arrival, the pilot flew three circuits, with one at low level, in order to familiarise himself with the airstrip before positioning to land on grass Runway 28, which was about 530m long and had an uphill slope.
At the end of the runway were several farm gates that led to an adjacent field, bounded by a hedge, which was used for livestock. The reported wind was from 100° at 7kt.
The pilot recalled configuring the aircraft for the approach with the propeller set to its fine position, carb mixture fully rich and flown at a speed of 60kt. The pilot stated that the flaps were set at an intermediate position between 20° and full flap.
A witness next to Runway 28 recorded video footage of the aircraft as it landed. The final sequence was not recorded, but the footage showed that the aircraft touched down about halfway along the runway. It stayed on the ground for a further six seconds before the video ended. At this point it was estimated that the aircraft was about 110m from the end of the runway.
The pilot stated that as the aircraft touched down, he saw a horse appear near the end of the runway and almost immediately initiated a baulked landing. At the same time, the passenger also expressed the need to go-around, as the aircraft had landed further along the runway than intended. The pilot stated that he then set the flaps to 20° and advanced the throttle to the full power position, but the aircraft did not accelerate as expected. As the aircraft approached the end of the runway it started to become airborne, but then hit the farm gates.
The aircraft then touched down in the adjacent field, overturned and ended up inverted. The pilot and passenger were uninjured and vacated the aircraft unaided, but the
Safety Accident Reports
aeroplane was damaged beyond economic repair.
The pilot considered that the aircraft did not accelerate and climb as expected because of a possible loss of engine power or malfunction with the constant speed propeller. Comment: The AAIB did not determine a cause, but as we know landing on a relatively short strip with a tailwind can be a challenge, even with an upslope and everything working for you. It all happens in a bit of a rush until it comes to getting airborne again, such as in the event of a baulked landing when it takes forever. That makes a late-decision go-around really fraught. Add to that a possible mechanical problem…
Watch out for FOD…
Glos-Airtourer 150 G-AXIX Almeley Wootton, Herefordshire Injuries: None
The aircraft was being flown to a grass airstrip near Almeley Wootton (approximately 5nm south-west of Shobdon). The pilot made an approach to land on the northwesterly runway with the wind about 5kt across. The pilot reported that he landed on the main wheels, but as the nosewheel touched down the aircraft started to oscillate in pitch. The nosewheel detached, the propeller struck the ground and the aircraft came to a sudden stop. Neither occupant was injured and both exited the aircraft normally. The pilot believes the accident was caused by a slightly higher ground speed than he was used to, due to the lack of headwind, as well as him closing the throttle slightly early, causing the aircraft to drop onto the runway. He was aware that he was landing on a short runway so did not want to land too far along it.
The pilot reported that as the aircraft came to a sudden halt the fire extinguisher, mounted at the back of the baggage compartment, came loose, went past the passenger’s head and through the windscreen. Once the aircraft is fixed, the pilot intends to relocate the fire extinguisher behind the seats to ensure it is secure. Comment: While there are lessons to be learned from the accident itself, I was struck by the detachment of the fire extinguisher! Photographs show that it punched a neat hole in the windscreen, and I couldn’t help but
reflect on what might have happened if the baggage hold was stuffed with Beaujolais, or whatever else we carry around ‘down the back’. Sudden stops can happen – even in aircraft.
Honest reporting
Piper PA-28 Warrior II G-BODB Sherburn in Elmet Airfield, Leeds Injuries: None
The aircraft was parked close to the airfield fuel pump installation. The pilot carried out his pre-flight inspection and, passenger boarded, started the engine. He taxied the aircraft forward before making a right turn, and during the latter stages the outboard section of the left wing leading edge struck the fuel pump. The pilot immediately shut down the aircraft and inspected the wing, which had a small dent on the leading edge. Having inspected the damage, which he considered was minimal, he considered that it would be safe to fly. It was late afternoon and he had to complete the flight before night, but he did not want to disappoint his passenger, so he pushed the aircraft back, restarted the engine and departed.
Due to the delay, however, he then landed about 15 to 20 mins into night time. He reported the contact with the fuel pump and having flown at night to the flying club. It made clear to the pilot the action he should have taken – getting the damage inspected and curtailing his flight to avoid flying at night. Comment: The club was correct in pointing out to this low hours PPL holder such an incident should be handled. Hats off to the pilot for reporting the events. Honest reporting, without any fear of recrimination is a big step towards safer flying. May there be more of it.
Safety kit
Emergency storm shelter
£18.50 | https://bit.ly/3hGm1jF
While the Lomo shelter is probably an essential piece of kit for the more adventurous among us, most occupants rarely fly ‘dressed to survive’, so having this on board could certainly be a life saver.
It is made from high-viz orange, PU-coated polyester and has two large retro reflective patches on the front to help reflect the torch light from a search party or helicopter searchlight.
A viewing window is also included to let the occupants see out, while keeping sheltered, and two air-vent snorkels help with ventilation. These can be adjusted or closed in heavy winds and rain.
This type of emergency shelter,
sometimes referred to as a ‘bothy bag’, is in common use by hill walkers, and weighing-in at only 360 grams makes it practicable to carry airborne too.
The dimensions are: 21cm x 10cm (when folded away) and 1.3m x 96cm x 45cm (when erected).
