The Boeing 787 Dreamliner crashed mere minutes after it had taken off from Ahmedabad airport on June 12, plummeting into a residential area, called Meghani Nagar, while claiming 19 more lives of those on the ground.
Aircraft Accident Investigation Bureau (AAIB) have released the first forensic details into the tragedy which could reveal the cause of what is said to be one of the worst tragedy’s in india’s aviation history.
Among the fresh information, is the final conversation between the doomed aircraft’s pilots, captured using the cockpit voice recording, suggesting the fuel had been ‘cut off’ in their final moments.
Amid the perplexity, one can be heard asking the other why ‘did you cut off’ the fuel supply, while the other responded he ‘didn’t’, according to a report by Indian authorities.
It did not identify which remarks were made by the flight’s captain Sumeet Sabharwal and which by the co-pilot, Clive Kunder, nor which pilot immediately transmitted the distress call: ‘Thrust not achieved… falling… Mayday! Mayday! Mayday!’
The Boeing 787 Dreamliner is thought to have lost power when the fuel cutoff switches almost simultaneously flipped, starving the engines of fuel, according to the report by Indian accident investigators.
The pilots’ exchange prompts a key question over the crash – who could those fuel switches, which are designed to be ‘highly reliable’ and are constructed to stop unintentional activation, be accidentally flipped mid-flight?
Each lever has to be pulled upwards to be unlocked, before it can be flipped and they also have further protective guard brackets to safeguard against any bumps and nudges.
‘It would be almost impossible to pull both switches with a single movement of one hand, and this makes accidental deployment unlikely,’ a Canada-based air accidents investigator told the BBC.
John Cox, U.S. aviation safety expert, said a pilot would not be able to accidentally move the fuel switches that feed the engines. ‘You can’t bump them and they move,’ he said.
But the plane only ever reached as high as 625ft, immediately beginning to lose thrust and sink down moments after setting off to London, later exploding into a fireball after smashing into a hostel on the ground in Gujarat, killing all but one on board.
Investigators’ early assessments indicate no apparent fault with the Boeing or its engines, suggesting that Boeing and engine maker GE had no apparent responsibility for the accident.
The report from the Aircraft Accident Investigation Bureau, published late on Friday, said the jet was carrying 54,200kg of fuel, which was within the ‘allowable limits’. Fuel samples retrieved from the aircraft’s refuelling tanks were also deemed ‘satisfactory’.
‘The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec,’ the report said.
‘The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off.
‘In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so.’
But the report does not say how the switch – which is used to start or shut down the engines and are typically left on during flight – could have flipped to the cutoff position.
The aircraft slid across the roof of Building A where the right ending collided with a water tank structure and desperate from the airplane
Investigators are currently focusing on a previous Special Airworthiness Information Bulletin (SAIB) by the US Federal Aviation Administration in 2018, which said some Boeing 737 fuel control switches were put into the aircrafts with the locking feature disengaged.
Although the problem was never deemed unsafe, an Airworthiness Directive (AD), which is legally enforceable, was issued to correct the problem with some of the levers.
Boeing 787-8 aircrafts, as well as the Air India plane, use the same design switch. And due to the SAIB being recommended, Air India did not carry out advised inspections.
All pilots and crew had passed breathalyser and were deemed fit to fly, according to the report, which detailed how both Sabharwal and Kunder had enough rest before taking to the skies.
At the crash site, both fuel switches were found in the run position with the report detailing there had been indications of both engines relighting before the low-altitude crash.
An ex-investigator with India’s Aircraft Accident Investigation Bureau (AAIB) speculated whether the switch may have tripped due to possible issues with the plane electronic control unit.
Capt Kishore Chinta told the BBC: ‘Can the fuel cut-off switches be triggered electronically by the plane’s electronic control unit without movement by the pilot? If the fuel cut-off switches tripped electronically, then it’s a cause for concern.’
Referring to data recovered from the plane’s two Enhanced Airborne Flight Recorders (EAFR), it continues: ‘As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic.
‘Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN.
‘When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engine’s full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.’
Flipping to cutoff almost immediately cuts the engines, and is most often used to turn engines off once a plane has arrived at its airport gate and in certain emergency situations, such as an engine fire.
The preliminary report does not indicate there was any emergency requiring an engine cutoff.
The new findings appear to tally with theories reportedly put forward on the US side of the investigation, which also noted that the switches controlling fuel flow to the aircraft’s twin engines were turned off shortly after takeoff.
It remains unclear why they were turned off, and investigators have been left wondering whether it was deliberate, accidental or corrected too late.
According to a report in the Wall Street Journal, one potential sign that the switches were off was the deployment of the plane’s emergency power system, a Ram air Turbine or RAT.
The RAT usually comes into action when both engines lose power or if pressure in all three hydraulic systems are critically low – both essential components of keeping a flight going. The landing gear was also found in a downward position.
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Shawn Pruchnicki, a former airline accident investigator and aviation expert at Ohio State University said: ‘The deployment of the Ram Air Turbine (RAT) strongly supports the conclusion that both engines had failed’
He believes the pilot at the helm of the aircraft had no time to think. According to investigators, crew tried to act but the crash transpired to quickly.
If the preliminary findings hold, that would exonerate the Dreamliner’s manufacturer Boeing and engine developer GE Aerospace.
India’s Aircraft Accident Investigation Bureau said: ‘At this stage of investigation, there are no recommended actions to Boeing 787-8 and/or GE GEnx-1B engine operators and manufacturers.’
The agency, an office under India’s civil aviation ministry, is leading the probe into the world’s deadliest aviation accident in a decade.
Last month, the tragic crash claimed the lives of 169 Indian passengers on board, 53 British, seven Portuguese and a Canadian, as well as 12 crew members and left only one survivor – British national Vishwash Kumar Ramesh, 40.
At least 19 people were also killed on the ground as the doomed Boeing 787-8 Dreamliner came down in a residential area moments after takeoff.
Air India, the nation’s oldest airline, has been trying to revitalise its operations after several years under government control.
The airline company says Captain Sumeet Sabharwal, who was flying the plane, had more than 10,000 hours of experience on wide-body jets, while co-pilot Clive Kunder had logged over 3,400 hours.
The crash marked the first fatal incident involving a Dreamliner and was a major setback for Boeing, which is facing ongoing scrutiny over its aircraft safety standards.
The US National Transportation Safety Board is assisting with the Indian-led investigation, while the Federal Aviation Administration, Boeing and GE Aerospace are providing technical support. It declined to comment on the release of the report.
Reports indicate there have been tensions building between American and Indian officials.
One of the biggest points of contention is the delay in accessing and analysing the plane’s black boxes.
The Americans are not pleased with the slow pace at which data is being extracted from the cockpit voice and data recorders.
The US team at one point even considered pulling out of the probe before eventually deciding to carry on.
The US investigators have since returned home.
The Dreamliner, which was first delivered to Air India in 2012, has been used for many international routes.
Although officials have initially focused on the fuel control switches, they have cautioned nothing has yet been ruled out yet.
Sole survivor Vishwash Kumar Ramesh had been in the country on a business trip with his brother Ajaykumar, 35, before they boarded the doomed flight travelling from Ahmedabad to Gatwick on Thursday.
In what has been described as a miracle, Viswash – seated in 11A by the exit – survived, but his sibling who was sat on the other side of the aisle in seat 11J perished in the fireball explosion.
Before the discovery of the British survivor, authorities said that they believed no one had escaped the flight alive.
Eleven of those on board were children, including two newborns.
The Boeing jet crashed shortly after takeoff from Ahmedabad Airport in Gujarat at around 1.40pm (0810 GMT), officials said.
Ahmedabad, the main city of India’s Gujarat state, is home to around eight million people, and the busy airport is surrounded by densely packed residential areas.
Preliminary flight tracking data from flightradar24 reveals the plane reached an altitude of just 625ft after takeoff – a height far below standard for a commercial aircraft several minutes into departure.
According to data logs, recorded at 30-second intervals, the plane remained on the ground or was taxiing slowly for over four minutes after it first registered on public trackers.
The plane took off and reached 625ft, but no further gains in altitude were recorded before the crash.
An Air India spokesman said: ‘Air India stands in solidarity with the families and those affected by the AI171 accident. We continue to mourn the loss and are fully committed to providing support during this difficult time.’
The spokesman added: ‘Air India is working closely with stakeholders, including regulators.
‘We continue to fully co-operate with the Aircraft Accident Investigation Bureau (AAIB) and other authorities as their investigation progresses.
‘Given the active nature of the investigation, we are unable to comment on specific details and refer all such enquiries to the AAIB.’
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