9 minute read
Accident Analysis – Surprises all round…
Although sharing our cockpits with fellow travellers has been a bit more tricky of late, the good times will return. When they do, Steve Ayres suggests its worth reflecting on some of the potential consequences of doing just that…
Few of us ever have the opportunity to ride in a fast jet and fewer still actually own one, so it is perhaps debatable as to why this month’s analysis should begin with a look at a rather scary passenger ride on one of Martin Baker’s finest ejection seats. The accident report, compiled by the French Air Force, runs to some 40 pages and is an excellent study into the sort of issues that often arise with passenger flying. Most are entirely relevant to General Aviation so I make no apologies for using the report and thank my French colleagues for their candidness.
Advertisement
Accident 1
Saint-Dizier is a French Air Force base on which ETR 3/4 Squadron is dedicated to the conversion of Rafale crews. They were tasked with carrying a 64-year-old civilian passenger, in charge of testing teams at a weapons company and who had no military aviation experience.
The morning of the flight, the passenger underwent a medical examination for approval to fly in an aircraft equipped with ejection seats. Followed, on the Squadron, by a specific clothing and equipment session, plus training in safety-rescue systems focused on the ejection seat. The passenger then briefly participated in part of the mission briefing with the other aircrew before joining his four companions for lunch.
For the flight, the passenger was installed in the rear seat and the pilot adjusted the various passenger restraint straps on the seat. The passenger’s installation was checked by the ramp engineer. After start-up and taxying, the aircraft lined up in echelon behind the other two aircraft for a 30 second stream take-off. The take-off run was normal and once airborne the pilot retracted the landing gear to accelerate. He then performed a standard climb profile, rotating to a pitch attitude of 47°, with a load factor close to 4g, followed by a bunt close to -0.6g for the level off. During this last phase at 650ft and 280kt the passenger was ejected from the aircraft. The pilot recovered the aircraft to Saint-Dizier and evacuated without assistance.
The investigation discovered that the flight recordings used for maintenance and for the mission itself were automatically erased because the ejection system had been initiated. However, enough flight data was accessible to reconstruct the flight profile. The passenger’s connected personal watch recorded his heart rate. Examination of the onboard conversation indicated normal dialogue up to, and including, the take-off acceleration with the passenger falling silent as the climb commenced. The ejection handle showed the presence of glove fibres which indicated the ejection had been initiated by the passenger.
Observations made on the harness after ejection in conjunction with photographs taken by work colleagues, indicate the shoulder straps were inadequately tensioned.
A number of possible reasons for the rear ejection handle being pulled were considered by the inquiry, including voluntary activation through loss of consciousness (such as A-LOC or G-LOC) or high levels of stress, but all were rejected in favour of involuntary activation. The passenger was under significant stress throughout the morning. The data indicates that his heart was in full tachycardia with a rate that ranged between 136 and 142bpm against a maximum heart rate of 156bpm.
The passenger’s level of stress was exacerbated by the context of the flight. Given the tight deadlines for the programme, the passenger did not take part in the full mission brief and his pilot did not have time to talk through the key aspects of the sortie. Once airborne the stressors were initially the positive load factors. At +3g a feeling of great heaviness of the limbs and the body in general, between +3g and 4.5g: possible appearance of a grey haze (narrowing of the peripheral visual field associated with blurred and darkening of vision) and over 4g the appearance of a black veil (total loss of vision). As this was his first flight in a high performance aeroplane, the passenger would have been unaware of these symptoms and would have found them stressful. The initial positive-g phase was followed by rapid transition to a negative-g phase (-0.63g). On the ground, humans are rarely exposed to a negative load factor and the sensation would have been unfamiliar to the passenger. This feeling may have been enhanced by his harness not being properly adjusted allowing him to rise up in the seat. The passenger was therefore not prepared for what would take place during the take-off and the positive g at rotation and its subsequent reversal would have significantly added to his stress. This likely explains why the passenger involuntarily pulled the ejection handle in order to grab onto his seat and counter the feeling of being thrown from the cockpit.
This flight was organised by colleagues close to the passenger without notifying him in order to maximise the effect of surprise. He had never expressed a desire to carry out this type of flight nor in particular in a Rafale. Maintaining the surprise led to a reduction in the time taken for each stage of preparation for the flight: medical examination, clothing and ejection seat briefing. This situation generated a feeling of stress for the passenger, which was particularly felt during the ejection seat briefing where he had to assimilate a great deal of information in a very short time. In addition, the stress of surprise was magnified by the complete lack of military aviation experience.
The passenger said he had a complete ignorance of the aviation environment and its constraints, having never flown on a military aircraft. Such a situation reduces a person’s capacities to make decisions and, faced with a fait accompli on the day of the flight, it was very difficult to refuse to take part. Additionally, organisation of this type of flight by co-workers, especially when it is so rare, can create a feeling of exception.
Social pressure from the company, represented by a large number of colleagues present made any refusal extremely difficult. This type of flight was relatively routine. However, unlike the majority of flights, the programme for this day was the subject of a memorandum which stipulated a meal with the base commander, the presence of numerous accompanying persons and a ‘photo record’ provided by the base PR unit. Additionally, the memo did not provide for any secondary solution in the event that it was impossible to conduct the flight, for example a flight in the simulator, further emphasising the desire to carry out the mission as planned. The passenger was considered a VIP and consequently no one felt in a position to query the flight.
Both pilot and passenger suffered slight injuries, mostly minor lacerations from detonation of the canopy.
Accident 2
The pilot of a Javron PA-18 Super Cub stated that he was planning to perform an off-airport landing on the shore of a reservoir where he had successfully landed many times before. After about a 30-minute flight, the pilot configured the aeroplane for landing on the shoreline. During touchdown, the passenger, who was in the rear seat, inadvertently applied the brakes, causing the aircraft to nose over inverted.
Accident 3
The pilot of the Beech 55 reported that, shortly after landing, the passenger, without his permission or guidance, retracted the landing gear. The aeroplane impacted the runway, slid about 600ft, and then came to rest. The pilot-rated passenger reported that, without the pilot’s guidance, he mistakenly raised the gear handle then quickly lowered it again, thinking it was the flap handle, and that he was attempting to assist the pilot. The aeroplane sustained substantial damage to the centre wing spar.
Ayres’ Analysis
Does any of the above sound familiar? Ever received or thought about giving a surprise flight to a colleague? A birthday gift or a special occasion, perhaps? Ever been a bit rushed to get your passenger strapped in and airborne before the weather comes in or the airfield back home closes? If we haven’t been there already, we almost certainly will at some point in the future, and although we may cope well with the pressures, do spare a thought for the passengers. In most instances the flight is for their benefit, and if they are to properly enjoy it, make sure you set aside ample time and leave space in the programme for the unexpected. Have a back-up plan, too.
Better to find an alternative means of transport than have your passenger scared witless and risk them doing harm to themselves or even your beloved aeroplane! Give yourself time and talk through every aspect of the sortie and describe the sensations they may experience. As much as it may be fun to elicit the odd ‘squeal of delight’ from your passenger, when accompanied by an elevated heart rate and stress, they may do things you least expect.
Landings, in particular, can be scary to the uninitiated and your passenger may respond unexpectedly. Such as applying the toe brakes during the landing run, as occurred in the Super Cub accident.
I would put my money on the Rafale passenger having been told countless times to keep his hands off the ‘black and yellow’ thing between his legs but, under stress, he couldn’t resist!
Be thorough and do the job properly, perhaps consider using a passenger brief. Strap your passengers in carefully. If the going gets bumpy or you plan on doing aeros, they will thank you for doing so correctly. Point out the ‘do touch’ and the ‘do not touch’ bits of the cockpit. A bit more important with tandem seating, but as the Beech accident shows, things can still get moved unexpectedly in a side-by-side cockpit. Remember too, your passengers will forget most of what you tell them and, in the heat of the moment, will probably get actions wrong. Talk about evacuation and what to do if things don’t go as planned, but try not to scare them. It is a fine balance and a matter of judgment as to how much to say and how much to simply take ‘on risk’.
You need your passenger to be a thinking, coherent and hopefully unstressed individual by the time you get airborne, not a gibbering wreck with a heartbeat approaching their maximum!
In the final analysis, the whole experience needs to be fun and if it’s not going to be why not just admit it and try again another day. Or, simply accept that flying is not your passenger’s ‘thing’.
Footnote - Although I would not recommend end-to-end testing of your escape systems to the extent the Rafale pilot did, it is worth noting that a failure of the seat interconnect prevented what should have been a double ejection and certain aircraft loss. Gods can sometimes smile even in the gloomiest of circumstances!
