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Louis Ibah
A final report on the investigation conducted by the Nigerian Accident Investigation Bureau (AIB) on accidents involving Bristow Helicopters, International Aviation Colege Ilorin, Nestoil Gulstream, and a Cessna 208B Caravan aircraft flown by Mr. Dambaba Suntai, a former Taraba State Governor, has blamed the four accidents on ‘human errors’ even as it called for stricter implementation of its safety recommendations by relevant stakeholders involved in the accidents.
Reasons for investigation
Olateru in the report said the core essence of the AIB investigations was not to serve as a punitive measure for those that erred, but rather, to serve as measures that would prevent the future reoccurances of similar accidents.
“Accident investigations are geared towards having a safer airspace for air travellers and therefore the purpose of our investigation is not to apportion blame, but to prevent future recurrences of similar incidents or accidents,” said Olateru.
“Relevant stakeholders (aircraft manufacturers, governments, airline operators, pilots, engineers, regulators, airport managers) who had access to accident investigation reports should always draw safety lessons that are applied to mitigate future re-occurrences of similar events,” Olateru added.
Aviation rules and practices are governed by the International Civil Aviation Organisation (ICAO), a United Nations agency saddled with the responsibility of regulating the global aviation industry and through a document known as Annex 13 to the UN Convention and under which all signatory nations are obliged to respect.
When notified of an accident, the national investigation agency deploys a team to the site – in Nigeria, this is done by a team from the Accident Investigation Bureau (AIB). Generally the team includes investigators, comprising the most experienced pilot with background on that aircraft type; persons with an engineering background on that aircraft type; and others specialising in flight data recorders. Investigators are trained to set out with the sole aim to test hypotheses with the evidence, rather than collect evidence to support a theory.This is also the reason why, sometimes, investigations can take many years to complete. The ICAO suggests one year as a target, but it many take longer depending on the complex nature of the accident and how quick investors arrived at the scene to protect essential evidences from being tempered with.
Investigators usually start with a rational overall assessment of the accident site. Sometimes there may be more than one area of interest – for example, where the aircraft stalls and breaks up in a flight as happened in the Associated Airlines crash in Lagos conveying the corpse of former Ondo State Governor for burial,and where debris is scattered over many square miles.
In other cases, evidence may lie at the departure airport or at the aircraft’s home maintenance hangar. Experienced investigators will say that they let the accident site tell the story, taking in the full picture rather than immediately focusing on the forensic detail. It is for this reason that those in the aircraft accident investigation business will often shake their fists at so-called experts and theory analysts whose speculation fill initial news reports after any crash.
Physical aircraft wreckage
The physical evidence that remains after the crash of an aircraft is of great importance and is generally subjected to various types of imaging, such as photography, laser scanning (LiDAR), and airborne or satellite imaging by investigators. Minor details such as dents and paint scrapes all provide the investigators with details to help decipher the flight’s last moments before crashing.
Often the best way is to physically piece together the wreckage. In doing so, it’s possible to see how the structure broke apart, or to check for residues of explosives or tell-tale impact marks. This task is much easier when reconstructed in three dimensions rather than looking at individual pieces of metal laid out on a hangar floor. The clues gleaned from this process can be corroborated against those from elsewhere, such as post-mortem results of the occupants, closer forensic examination of the wreckage, or flight recorder or radar data.
Investigators also bring in technical advisers for their specialist knowledge on an engine or aircraft frame where it becomes imperative to examine damaged engines, looking for signs of metal fatigue or contamination before they are stripped down to avoid losing precious evidence during dis-assembly. Here, computer and physical simulations are deployed.
Black boxes
Once an accident occurs, the two immediate challenges investors face are the 100 per cent isolation of the crash site and preservation of all evidences and the recovery of the black box.
This amazing device, the “black box” comprises the Digital Flight Data Recorder (DFDR) and Cockpit Voice Recorder (CVR) and it records the last two hours of sound on the flight deck between the pilots and air traffic controllers as well as many hours of essential flight data such as control inputs, heading, speed, altitude, and the status of systems such as engines and cabin air supply.
Investigators have to find this box from the aircraft wreckage whether on land or sea download the information in a laboratory and analyse it. It usually holds the greatest clue for investors to decipher what went wrong in the course of a bad flight. It is of note, that the cause of the majority of air accidents have been discovered by replaying the audio tapes of conversations by the two pilots (and sometimes with air traffic controllers) while trying to manage a mechanical, electrical, engine flaw in an aircraft or any other sudden bad situation that develops either during take-off, mid-air and aircraft landing.
Operators, regulators responsibilities
Indeed, at the end of an accident investigation, the investigating agency (the AIB) not only reveals the cause of the accident, but it also issues ‘safety reports’ which states clearly what ought to be done in the future to mitigate such identified mechanical or electrical faults on the aircraft by its manufacturers or if it’s a human errors, what the airlines, regulators, airports, and aircraft operating crew should do to forestall similar occurrences.
According to the AIB boss, the agency is worried that some of its recommendations have not been fully complied with in the country. For this reason, the AIB recently instituted a team to find out the compliance level of its safety recommendations on the accident reports released in the last 10years.
“Safety recommendations are very important towards preventing reoccurrence of similar accidents and when adhered to impacts air safety positively,”Olateru said.
