DUBAI // Months of painstaking work sifting flight data, witness accounts and physical evidence will be needed to find out why and how Emirates flight EK521 crashed, according to an air safety expert.
An investigation team led by the General Civil Aviation Authority with support from the 777 aircraft manufacturer Boeing and engine maker Rolls Royce began to examine the evidence hours after the accident on Wednesday.
Ian Holder, principal consultant at the UK-based aviation safety consultancy Baines Simmons, said the investigation into the crash at Dubai International Airport could take between six months and a year to complete.
“The main aim of an air accident investigator is to find what and why the incident happened so that we can learn from it and prevent similar things happening in future,” he said. “It is not to proportion blame.”
The investigation process begins with securing the site so that it was safe enough for the team to conduct their work.
“On this occasion the incident took place on a runway so it is already a secured area,” said Mr Holder. “It would be much more difficult to secure a location if the accident happened in a remote area or the sea, as evidence can quickly disappear.”
Ideally, on-site work should be completed as soon as possible because there is a danger of contanimation as more people come into contact with it.
“The site has already seen firefighters go onto the scene as well as others, so the sooner investigators can make their measurements and collect data, the better,” he said.
It was vital to retrieve the black box and cockpit voice recorder to help build a picture of what happened onboard. Investigators also take evidence of the placement of flaps and flight surfaces.
“Collection of physical evidence as well as eye-witness accounts in this period is very important because this type of data will become degraded,” he said. “People’s perception of what happened can change quickly.”
Once key information has been collected, the aircraft is moved to a secure location where the data will be analysed in greater detail.
“This means interviews with the pilots, air-traffic controllers, maintenance crews, aircraft manufacturers and the airline, among others, to develop a set of hypotheses, which will then be tested,” said Mr Holder.
“Aircraft are highly complex machines and so to have the manufacturer on-site can help to provide clarification for investigators in that regard.”
After all the evidence is gathered, it must be cross-referenced with what witnesses say and physical data, which is “very time-consuming”, Mr Holder said. It is important for investigators to corroborate evidence because it is not uncommon for people to have differing accounts.
“The idea is not to jump to a conclusion, but instead develop a set of hypotheses and keep challenging them,” he said.
If there is not enough evidence, the aircraft might be reconstructed to help show where the failures were, though this is more common for an accident that happened in the air rather than one the ground, Mr Holder said.
“Investigators follow a structure and they evaluate the facts and from that they get findings and draw conclusions. It is never one thing that would have caused an accident, but rather a series of variables that happened together to create the circumstances for the crash,” he said.
Aviation is an “extremely safe mode of transport”, Mr Holder said.
“If you’re someone who flies once a year then that is the safest journey you will have. The reason for that is we have learnt over the years how to put systems in place to reduce the risk of accidents.
“For an aircraft accident to occur, a series of complex variables will have happened.”
Emirates flight EK521 from Thiruvananthapuram, India, crash-landed at Dubai International Airport on Wednesday. All 300 passengers and crew on board were safely removed from the plane, but a firefighter, Emirati Jassim Al Baloushi, died from injuries sustained during the emergency response.
nhanif@thenational.ae
