The Air Accident Investigation Branch (AAIB) of the UK’s Department of Transport, Local Government and the Regions (DTLR) lays claim to being the world’s oldest team of aircraft crash investigators, dating its origins to 1915 as part of the Royal Flying Corps (RFC). Today, along with its U.S., French and German counterparts, AAIB commands worldwide respect in its field and now spends more than half of its time engaged in overseas accident investigations.
After its role during World War I, when the RFC was losing more pilots and aircraft to accidents than to enemy fire, the agency was charged with probing accidents in the fledgling civil air-transport industry. This followed pressure from members of the British aristocrats, who were alarmed by a spate of accidents in which several heirs to wealthy estates were killed. Early scheduled flights between London Croydon Airport and Paris Le Bourget were commonly forced to make unscheduled landings along the 230-mi route due to technical problems.
In recent years, the AAIB’s highest profile case was the investigation into the Dec. 21, 1988, terrorist bombing of a Pan Am Boeing 747 above Lockerbie, Scotland. After groundbreaking work on the effect of explosives on airframes, the AAIB’s 1990 report confirmed that Flight 103 had been blown apart by less than nine ounces of Semtex plastic explosives. The evidence was vital in the conviction earlier this year of two Libyans for the murder of the 243 passengers and 16 crew aboard the 747 and 11 people on the ground.
One of the main puzzles confronting the AAIB team was how such a small quantity of explosives hidden in a radio located deep down in the front baggage compartment had completely blown open the roof of the 747’s upper deck. With no model for the effect of explosives within so large a structure, the British investigators had to start from ground zero. They established that the explosion had sent “maxdem” pressure waves around the fuselage until they hit an obstacle in the shape of the upper deck floor. This caused the wave to punch a huge hole right through the upper deck.
This scientific breakthrough sparked research into the use of Kevlar composite panels (similar to those used in police body armor) to contain explosions within baggage containers. Two years ago the effectiveness of the panels was proven when UK researchers detonated a larger cache of explosives inside a retired Air France 747 and found that the damage was largely contained within the baggage compartment.
The panels have since been introduced into service by Israeli flag carrier El Al and by several royal flight departments. However, the vast majority of carriers have so far declined to install the panels.
A Logistical Challenge
The Lockerbie investigation presented AAIB with a vast logistical challenge and could not have been completed without the support of its partner organizations, namely the Royal Air Force (pathology, land salvage and aerial reconnaissance); the UK Defence Evaluation and Research Agency (human factors, aerodynamics and materials); the Meteorological Office (weather “after-casts”); National Air Traffic Services (radio transcripts and radar data); marine salvage contractors; and the Civil Aviation Authority (airworthiness, licensing and flight operations data). AAIB also regularly turns to aircraft manufacturers, aircraft overhaul firms, operators and universities for expert input.
From its cruising altitude of 31,000 ft, the Pan Am 747’s wreckage was spread over 845 sq mi spanning the west coast of Scotland, the Scottish Lowlands, northern England and the North Sea. Despite this, approximately 90 percent of the aircraft (by weight) was recovered and key parts of the airframe were reassembled in the hangars at AAIB’s Farnborough headquarters to help investigators deduce the cause of the accident.
At a July 26 press briefing, AAIB chief inspector Ken Smart stressed that the agency’s overriding goal is to ascertain the causes of accidents to prevent future incidents than to apportion blame. With this in mind, AAIB investigators do not publish the names of crewmembers or operators in their reports and do not release sensitive evidence such as cockpit voice recorder tapes. In the UK, the release of this sort of information requires High Court approval, with judges essentially being asked to determine whether the legitimate public interest in the information outweighs the possible negative effect on future safety investigations.
AAIB inspectors frequently receive invaluable insights into possible accident causes from primary sources such as airline crew and airframe engineers. With this in mind, the AAIB is concerned about UK government plans to introduce a so-called “corporate killing” law that could see the employees and management of aircraft operators and manufacturers facing criminal prosecution for manslaughter after fatal accidents. This would mirror existing legislation in many other European countries.
Smart told AIN that, in his view, the proposed “corporate killing” law will actively deter people from cooperating with AAIB investigations, with company attorneys expected to advise them that they risk incriminating themselves and colleagues. “I believe this could really impede the culture of openness that we have with our investigations,” he said.
Big Brother Watching?
Similar concerns are standing in the way of the introduction of video cameras inside and outside aircraft. Pilot unions, especially in the litigious U.S., are adamant that evidence from cockpit cameras could be seized and manipulated by attorneys looking for scapegoats on which to pin ruinous accident damages.
But the AAIB investigators are convinced that video footage could prove invaluable in figuring out what happened in the cockpit immediately before a fatal accident. Smart explained that without video from the cockpit, his investigators are undoubtedly missing important nonverbal communication between crewmembers. The AAIB’s approach to pilot union concerns would be to safeguard this material in the same way that they prevent CVR recordings from being made public, assuring crews that videos would be used purely for the purposes of getting to the root cause of the accident.
However, not all countries have demonstrated such a judicious approach to the handling of air accident data. Smart said that he and his colleagues had been “horrified” when CVR recordings of a recent accident involving an Airbus at Nagoya, Japan, were released to local TV stations within just a few hours and before investigators had even heard them. The tapes were actually broadcast before all the victims’ families had been notified and the family of at least one crewmember was traumatized by hearing his last despairing cries. Similarly, Air New Zealand crews threatened to disable CVRs by tripping their circuit breakers after an incident in which police released a recording from an accident involving a Dash 8.
In recent years, the introduction of internal and external video cameras has been on the agenda of the International Civil Aviation Organization’s accident investigation and prevention group (AIG). But the moves have been stalled over a failure to reach consensus on both legal and technical grounds. At the next ICAO assembly, which convenes in Montreal later this month, UK government delegates are planning to present a working paper calling for video cameras to be installed in new aircraft starting in 2005.
Pressure for the introduction of cockpit cameras was intensified by the October 1999 fatal crash of an Egyptair 767-300ER off Nantucket Island, Mass., after suspicions of possible sabotage in the cockpit were raised. Similarly, the January 1989 crash of a British Midland 737-400 at Kegworth near East Midlands Airport added weight to arguments for external cameras after it became apparent that the crew had inadvertently shut down the wrong engine in response to a fire warning light.
Quite apart from legal liability issues, there is still substantial debate over the reliability of video cameras and how they can best be positioned on an aircraft. Smart would clearly like to see the air-transport industry capitalize on advances in miniaturized cameras that he argued “could be fitted almost anywhere.”
Changes in the Works
This year’s ICAO assembly will confirm some significant changes to Annex 13, including the adoption of a new chapter with the following provisions:
• A requirement for states to establish mandatory incident reporting systems to collect information on actual or potential safety deficiencies.
• A recommendation for states to establish voluntary incident reporting systems to complement the information captured by mandatory reporting systems. Such systems must be non-punitive and afford protection to the sources of the information.
• States to share with other states safety-related information from their accident and incident databases as soon as possible.
• States to promote safety information sharing networks among all users of their aviation systems, including the free exchange of information on actual and potential safety deficiencies.
The assembly is expected to ratify the AIG’s proposal for the recording duration of CVRs to be extended from 30 min to two hours. It will also call for the establishment of a flight-data analysis program in which operator’s will be urged to use information collected onboard their aircraft as part of their accident prevention and safety program (rather than simply for maintenance and performance purposes).