Air India Crash Report To Offer Insight Into Fateful Seconds
Both the cockpit voice and the flight data recorders were retrieved from the wreckage, and their content was extracted by Indian authorities.
A month after the worst aviation accident in India in decades, authorities are poised to release a preliminary report into the catastrophe, offering the first official clues to what caused the aircraft to plummet back to the ground just 30 seconds after taking off.
Investigators have revealed very few details since the Air India accident, and the report also stands to be basic and factual — if previous initial findings are any guide. Authorities are unlikely to draw definitive conclusions or assign blame, as their work continues in the coming months to piece together a complicated puzzle of what happened on the Boeing Co. 787 Dreamliner on June 12.
What is known is that the aircraft, fully loaded with fuel, quickly lost altitude and slammed into a hostel for medical students, where it exploded, killing all but one of the 242 individuals on board and more than 30 people on the ground. The pilot issued one mayday alert before Flight AI 171 crashed in the western city of Ahmedabad.
Videos that have circulated widely of the plane’s takeoff and brief time in the air show that “everything is normal until they don’t put in the (landing) gear, and very shortly after the aircraft is losing thrust,” said Bjorn Fehrm, an aerospace analyst and former fighter pilot.
What’s unusual is that the power loss appears to be simultaneous in both engines — there’s no puff of smoke that would indicate a bird strike, or yaw by the aircraft that would be typical if one engine failed first. The 787 Dreamliner and other commercial planes have more than enough power to complete a takeoff on a single engine, and pilots are well-prepared for that event.
But as to scenarios where both engines power down simultaneously? “That’s improbable like hell,” Fehrm said.
Some potential key factors have begun to emerge, despite a lack of briefings or updates from the local government or India’s Aircraft Accident Investigation Bureau, which is leading the probe. Both the cockpit voice and the flight data recorders were retrieved from the wreckage, and their content was extracted by Indian authorities.
One particular line of inquiry is the movement of fuel control switches that sit in the center console of the cockpit, according to people familiar with the matter who spoke confidentially because the information isn’t yet public. The devices are used to turn fuel supply on and off to two engines made by GE Aerospace.
It remains unknown whether the pilots toggled the switches — either inadvertently or intentionally — and when during the flight the movement may have occurred. The detail was first reported by The Air Current, an aviation trade publication.
An aircraft tire among the debris at the crash site of Air India Ltd. flight AI171 in Ahmedabad on June 12.
The Wall Street Journal reported Thursday preliminary findings indicated the fuel switches were turned off, though it’s unclear whether that was accidental or intentional and whether any effort was made to turn them back on, according to people familiar with the situation.
A representative for GE Aerospace declined to comment. Boeing referred questions to the AAIB. The National Transportation Safety Board also referred questions to Indian authorities. Boeing and the NTSB have been assisting the investigation, though the Indian authorities have taken the lead role in the probe.
India’s air accident authority didn’t immediately respond to an email seeking comment.
Aviation accidents are usually caused by multiple factors and investigators are exploring a wide range of aspects related to the crash.
So far, investigators also haven’t found any evidence that would suggest the crash was caused by a design or mechanical problem with the Boeing aircraft or the GE engines, according to the people familiar with the matter.
They pointed to the fact that neither company, nor the US Federal Aviation Administration, has sent out any notices or safety bulletins to operators, which they said would normally occur quickly if an issue that could impact other 787s in operation was identified.
The people conducting the probe are also looking at the backgrounds and experience of the pilots — a normal step for this kind of investigation. The aircraft was in the command of captain Sumeet Sabharwal and first officer Clive Kunder, who had 8,200 and 1,100 flight hours, respectively, according to a statement from the Directorate General of Civil Aviation.
It’s widely assumed that the doomed 787 had a dual engine failure, especially after early evidence indicates that an emergency backup power source, known as the ram air turbine, was deployed.
But restarting the engines at the low altitude and speed at which the 787 found itself just seconds after takeoff wasn’t feasible, pilots say, meaning that the cockpit crew simply didn’t have enough time to bring the engines back to life.
John Cox, a former airline pilot who’s now chief executive officer of consultancy Safety Operating Systems, said that moving a switch to the cutoff position would shut off fuel supply to an engine. A dual failure would occur if the switches for both engines on the 787 were shifted.
“If you move those switches from run to cutoff, those engines will stop running in literally seconds,” Cox said.
A deliberate moving of the switches can’t be ruled out, he said. But there are also other possible scenarios, including that one engine failed and the pilot reached down to flip the switch for that engine but instead shifted the switch for the good engine.
It wouldn’t be the first time this kind of mishap occurred — a Delta Air Lines Inc. pilot in the 1980s mistakenly cut off fuel to the engines of the Boeing 767 he was flying. But in that case he was able to restart them because the aircraft was higher in the sky, avoiding catastrophe.
Pilots may also move the fuel switches in response to a dual engine failure. An emergency checklist that pilots need to commit to memory instructs aviators to cycle the fuel switches to cutoff and then back to run in the event of such a failure.
Moving the levers to cut off and back on allows the electronic engine control system to reset, according to several pilots who fly the airplane and spoke to Bloomberg.
