When you bend your aircraft the Air Accidents Investigation Branch should be your first port of call. One of Pilot’s contributors suffers a heavy landing and is perplexed by the paperwork, and the AAIB invites him – and the Editor – to its Farnborough base

Aircraft accidents lending themselves to news headlines and television documentaries as they do, the detective work done by the Air Accidents Investigation Branch is familiar to most people. We’ve all heard of ‘black boxes’ and the secrets they reveal, and – especially after yet another Channel 4 programme on the subject – can there be a person in the country who doesn’t know of the famed Farnborough investigation that revealed the Comet airliner’s fatal flaw; those square windows?


While you and I know that black boxes are properly called flight data recorders and have for many years been coloured orange?and that it was not so much that the Comet’s windows were square but they, and the similar radio hatches that did actually fail, were simply not sufficiently fatigue resistant?we’d all recognise the towering reputation the AAIB has built as an organisation that does a brilliant job of investigating aircraft accidents in a manner beyond reproach.


Or would we? While the quality of the Branch’s investigative work in those headline crashes commands respect, there have been mutterings in the general aviation world: could the AAIB, so expert on the big stuff, have been missing the point when it came to grassroots aviation? Were its investigations sometimes veering towards the CAA party line? Ironically, Pilot got the chance to put these questions directly to the AAIB when Contributing Editor Bob Grimstead bent his aeroplane and was invited down to Farnborough by Operations Inspector Mervyn Counter to talk about the four-page questionnaire he’d had to complete.




Not part of the CAA


The first thing you need to know about the Air Accidents Investigation Branch is that it is most definitely not part of the Civil Aviation Authority. Actually a branch of the Department for Transport, the AAIB is independent of the aviation authority, aircraft manufacturers and operators. Nor does the AAIB exist to put people in court: it is aimed at simply establishing what happened in an accident or serious incident?and what factors may have contributed. Its blame-free investigation process has become a model for European practice.


The AAIB’s sole objective is to improve aviation safety. In order to protect the free flow of information essential to its investigations, it is prevented by statute from disclosing the names of witnesses or other individuals who have supplied information. Interestingly, the AAIB has no formal obligation to investigate accidents involving ‘non-EASA’ Annex II/sub 2,060kg aircraft?but it continues to do so on a discretionary basis.


No small part of the motivation comes from the fact that, as Principal Inspector Julian Firth puts it, “we all fly regularly”. AAIB investigators and engineers are required to stay current and, as Pilot discovered during its visit, fly everything from airliners and jet warbirds to light aircraft, including microlights and gliders. Operations Inspectors are required to hold an Air Transport Pilot Licence and stay current through special arrangement with the airlines, flying as part of the operating crew on scheduled services. Engineering Inspectors must have a degree-level qualification or the equivalent, and hold a PPL. The point is that whether you are involved in an accident to a commercial jet of or microlight, it will be investigated by a pilot like you?someone with experience on your class of aircraft.


And what constitutes a reportable accident/incident? If the hangar door comes off its runners and falls on your aeroplane, it’s pretty clear that this is not an air accident nor, in the wider scale of things, a ‘serious incident’. If you start up and then clip the hangar door, then perhaps it should be reported…When this speculation is put to Mervyn and Julian, they come up with the simple definition: any event that results in substantial damage or personal injury after anyone has boarded an aircraft with the intention of flying (the formal wording is to be found at www.aaib.gov.uk).


Julian cites a neat example of how even this can be open to interpretation: if the engine fails at circuit height and the pilot glides down to make an uneventful forced landing on the runway, it isn’t technically a reportable occurrence?but if the same thing happens and the landing is on a rough surface off-airfield and results in damage to the undercarriage, it is. “If there’s any doubt about it, it’s better to call us and we will advise,” adds Mervyn.






Dial A for AAIB…


Well, 01252 512299 actually: the immediate point of contact is the Branch’s incident room, manned on the day of Pilot’s visit by Vickie Marsh and Karen Culverwell. Karen, Vickie and their colleagues receive the bulk of the 900 or so notifications of accidents that come in every year. The activity is proactive in that the main news channels are monitored continuously on flat-screen TV monitors mounted on the wall. Outside office hours, calls are redirected to the Principal Inspector on duty – the service is, as you would expect, 24/7. Most of the reportable accidents sifted from those enquiries are dealt with by AARFs (Aircraft Accident Report Forms) submitted by the pilot or pilots involved. The AAIB sends out approximately 200 of these forms a year: as Bob found, they can be something of a pain to complete – but they do need to be catch-all documents, and to cover accidents beyond GA.


Inspectors must be ready to head out to the site of the most serious accidents the moment notice comes in. “It could be Blackbushe or Siberia?we have to keep our grab-bags ready,” says Mervyn. The nominal responsibility is to investigate occurrences in the UK, but the AAIB often receives calls for assistance from abroad?hence Mervyn’s reference to Siberia, where the accident actually involved a Bermuda-registered aircraft. The Branch provided expert assistance to its French equivalent, the BEA during its investigation of the loss of Air France flight AF447, the Airbus that stalled and then crashed into the Atlantic with the loss of all on board. Of course, that tragic accident left no survivor, nor was there any human witness. Vital to discovering what had happened were the black boxes, eventually recovered from deep water.


At Farnborough the AAIB has a newlybuilt and comprehensively-equipped FDR lab (flight data recorder laboratory). A selection of typical FDR units is on permanent display, and it is fascinating to see the progression from wire and foil recorders, through magnetic tape to the kind of solid-state devices that are mandated today. The latter class will survive almost unimaginable impact and temperature, being specified to withstand red heat (1,100ºC) for sixty minutes and 260ºC for ten hours.


GA’s own ‘black boxes’


Today GA has its own black boxes in the form of the data-loggers fitted to many new factory-built aircraft and homebuilts, and all the stand-alone devices we all take flying with us, whether it is the Flarm so popular with glider pilots, the Aware or any other GPS unit?or even your smartphone. “You can get more information from a GPS than you can from the five-channel recorder they used to fit to commercial airliners,” observes Flight Data Inspector Chris Scott.


Eyewitnesses can provide less reliable evidence: something that would-be inspectors learn at Cranfield University, where for many years an unannounced flying incident has been staged as part of their training course. “People tend to rationalise what they’ve seen, especially if they have contact with other witnesses to an event,” says Mervyn. “Pilots’ recollections of events seen from the ground are sometimes less reliable than lay witnesses’ impressions. For example, because they expect aircraft to be coming from a certain direction?a nearby airfield, say?they will remember it doing just that, although the radar record proves it was on a completely different track.”


Mute witness to recent accidents, almost all of them fatal, is provided by the wreckage laid out in the AAIB’s hangars. Feature | AAIB You will have read about all of these accidents in the Branch’s Reports and Bulletins as well as Pilot’s ‘Safety Matters’, so the lessons to be learned will have gone home already: in any event, it would serve no useful purpose to describe or portray any of the individual wrecks we were shown. Suffice to say that while the most violent of impacts, the classic controlled flight into terrain, can transform an aeroplane or helicopter into a scatter of mangled components, the irony is that key components like engines often survive in condition that allows them to be run?and eliminated as a factor in or possible cause of the accident.


Other conclusions can be drawn from fragments of wreckage: propellers under power bend forward on striking the ground?and fold back if the power’s off; instrument pointers and control levers can leave tell-tale impressions of their position at the time of impact; and lighted warning bulb filaments may part in a unique way, while those in unlit bulbs alongside may all remain intact. However, the helicopter accident described in this issue’s Malone’s column (p.21) notwithstanding, very few pilots are killed as a result of simple mechanical failure.


While you can imagine being able to develop the necessary degree of professional detachment to be able to sift through the pieces to understand the mechanics of an accident, dealing with the human side must be far more difficult. “One of the greatest challenges,” Mervyn concedes, “is dealing sensitively with relatives of accident victims.”






Room for improvement?


It’s just as well, then, that the actual fatal accident rate continues to run at such a low level that it almost defies any statistical analysis?something that is in no small part due to the impartial reports and recommendations promulgated by the AAIB. Those recommendations are carefully considered, and do not appear in print until they have been peer-reviewed within the Branch and signed off by the Chief Inspector.


The Branch has won respect all around the world and remains the main provider of data to the European air accident database. Now commercial flight safety has been improved to a level unimaginable at the time the AAIB was formed, it is turning its attention to the proper conduct of accident investigation in developing countries.


However, there is always room for improvement. Perhaps the last word should go to Julian Firth; “One thing that would really help is more reporting of incidents. People in this country are generally very good at this kind of thing, but the more information pilots provide us with, the more we can do for flight safety”.




Bob Grimstead – We visited the AAIB because I complained about their four-page questionnaire. Why did I get those questions? Because I heavy-landed my Aeronca Champ, G-HAMP. I was annoyed that such a small incident meriting, I thought, no more than half a page in their next Bulletin, should take up a full morning of my time running around unearthing information that would never be published. I had better things to do, like repairing my battered little aeroplane! And I told them so; very brusquely.


After several subsequent phone conversations and our visit, I will gladly admit that I was absolutely wrong. Thanks to them, and the information they eventually teased out of reluctant old me, my ‘irrelevant’ prang actually resulted in a useful Safety Recommendation, and Mervyn Counter invited us to come and see their good work. Everything about the AAIB impressed me. Their premises were new, bright and spotless. Their staff were friendly, keen and clearly highly motivated. I already knew their detective skills and investigative doggedness were legendary, and their hangar full of sad, smashed wrecks was arresting.


But what really amazed me was their qualifications. Everybody we spoke with, whether field investigator or back-room boffin, seemed to be a current pilot, with a good spread of experience, including glider pilots, ultralighters, recreational GA fliers, homebuilders, ex-military, and regular airline pilots. Mervyn himself was not only a graduate of the Empire Test Pilots School – the world’s undisputed best – but had pursued two quite different military careers, swapping from heavy helicopters to large transport aircraft, while he now operates modern airliners from the left seat at least twice a month. He also flies warbirds. And this was just one of their many, multi-qualified, almost unbelievably experienced investigators.


I departed full of admiration and, while I had previously read every word of every AAIB Bulletin since they were first published, I shall now do so with renewed respect!


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