What exactly happened on flight AI171 between Ahmedabad and London Gatwick on Thursday afternoon will only be revealed after a detailed investigation, with investigators expecting the mystery to be solved by the "black boxes", i.e. the flight data recorders.
Indian investigators, in collaboration with experts from the US and the UK, will try to determine what caused the Boeing 787-8 Dreamliner to crash shortly after takeoff, just 1,5 km from the runway at Sardar Vallabhbhai Patel International Airport.
The Air India flight was carrying 242 people (230 passengers and 12 crew) when it took off from Ahmedabad International Airport to London Gatwick Airport. Only one passenger survived, who walked out of the wreckage. Vishwas Kumar Ramesh, 39, was seated next to one of the emergency exits.
Among the passengers were 169 Indian nationals, 53 British nationals, seven Portuguese nationals and one Canadian national.
Local police spokesman Kanan Desai told reporters that “265 bodies have been taken to the hospital,” meaning 24 people were killed on the ground when the plane crashed into a medical facility. The rescue operation ended early Friday with no further reports of fatalities.
Mayday
The Boeing 787-8 Dreamliner took off from Ahmedabad at 13:38 p.m. local time, bound for London Gatwick. Flight tracking data ends with the plane at an altitude of about 190 feet (XNUMX meters).
Before the plane crashed, the pilots sent a Mayday distress signal to the control tower, according to India's Directorate General of Civil Aviation.
The 787-8 Dreamliner was flown by Captain Sumit Sabhawal and his co-pilot Clive Kundar. The two were highly experienced, with more than 9.000 hours of flight time combined. Sabhawal had over 22 years of experience as a commercial airline pilot.
The captain of the fatal Air India flight warned that his plane was "losing power" seconds before it crashed into a building in Ahmedabad.
"Mayday! No thrust, losing power, unable to gain altitude," warned Captain Sumit Sabhawal as his plane began to lose altitude. However, after this message, the control tower received no news or further communication.
It is unclear what triggered the distress signal, but the sole survivor of the flight told Indian media that he heard a loud bang as the plane struggled to gain altitude.
India's Home Minister Amit Shah said the plane was carrying 100 tonnes of fuel - essentially a full load - as it took off from Ahmedabad.
Videos showed the plane flying low over a residential area. The final data transmitted showed the plane reaching an altitude of 190 meters. It continued to descend and was covered by trees and buildings, before a large explosion appeared on the horizon.
The scripts
While the search for the black boxes continues, experts are already recording scenarios for the causes of the tragedy, with two prevailing ones:
1. It must have been caused by an error in the adjustment of the blades and
2. A flock of birds entered the engines. Of course, there is always the possibility of human error.
Former British Airways pilot Alastair Rosenstein is among several experts who spoke to Sky News about their first look at the video of Flight 171, which showed some possible anomalies.
"He obviously has the landing gear down and that's not right... it should be up. And from the video... it's not particularly clear... but it looks like the aircraft didn't have the takeoff flap set."
Fins at the center of research
Aviation experts told the BBC that the position of the plane's wing flaps during takeoff may have been a problem. A video verified by the BBC shows the plane descending and a large explosion as it hits the ground.
As Jeffrey Thomas and Terry Tozer point out, video of the crash shows the landing gear still extended, while the flaps had already been retracted, which is not consistent with the intended takeoff procedures. Premature flap retraction could have led to a loss of lift and inability to climb. “The landing gear typically retracts within 10–15 seconds, while the flaps retract gradually over 10–15 minutes,” he explains.
Flight specialist Marco Chan said that the incorrect flap adjustment may have been due to human error, although a combination of many factors that contributed to the tragedy cannot be ruled out.
Bird collision
The possibility raised by some experts in India is bird strikes. They occur when a plane collides with a bird and can be extremely dangerous for aircraft. In severe cases, engines can lose power if they ingest a bird, as happened in the Jeju Air tragedy in South Korea, which killed 179 people last year.
The state of Gujarat, where Ahmedabad is located, reported 462 bird strike incidents over a five-year period, with most occurring at Ahmedabad airport, according to data from the Ministry of Civil Aviation tabled in Parliament in December 2023.
A Times of India report in September 2023 cited data from the Airports Authority of India reporting 38 bird strikes in 2022–23 in Ahmedabad, a 35% increase over the previous 12 months.
In the 2009 case, a flock of seagulls was swallowed by the water at 2.700 feet – more than four times higher than the Air India flight. In this case, the Indian pilots had neither the altitude nor the time to maneuver.
However, an experienced pilot said that a bird strike is rarely catastrophic "unless it affects both engines."
Speculation about "very rare" dual engine failure
It is almost impossible to definitively determine what caused the disaster based on videos of the plane's short flight.
A complex investigation will begin in the coming days, including the plane's black box - which records flight data - and examination of the wreckage. However, videos have been released showing the plane struggling to get off the ground, apparently amid a lack of thrust or power.
One cause that has been speculated by some experts is the possibility of an extremely rare dual-engine failure. Questions have been raised about whether the plane had deployed the Ram Air Turbine (RAT), an emergency backup turbine that activates when the main engines fail to produce power for essential systems.
Double engine failures are almost unheard of, with the most notable example being the 2009 “Miracle on the Hudson River,” when a US Airways Airbus A320 lost both engines to a bird strike shortly after takeoff from New York’s LaGuardia Airport, but landed safely.
A senior pilot told the BBC that the twin-engine failure could also have been caused by fuel contamination or blockage. Aircraft engines rely on a precise fuel metering system – if this system becomes blocked, it can lead to a fuel shortage and engine shutdown.
Marco Can, a former pilot, told the BBC that there was no evidence to suggest a double engine failure based on the available footage.
Mohan Ranganathan, an aviation expert, told the BBC that a double engine failure would be "a very, very rare occurrence".
Engine maker GE Aerospace said it had sent a team to India to help with the investigation, while Boeing said it was offering its full support to the airline.
First Boeing 787 Dreamliner crash
This is the first Boeing 787 Dreamliner crash, according to the Aviation Safety Network database.
The model, a wide-body twin-engine plane, has made five million trips in the 14 years since its first passenger flight.
Aviation expert Julian Bray told Sky News he understood the pilot managed to make a distress signal, meaning the crew were aware of a problem before the crash.
Air India was acquired by the Tata Group from the Indian government in January 2022 after it had accumulated losses of billions of pounds.
The group now operates more than 8.300 weekly flights on 312 routes, connecting more than 100 domestic and international destinations with a fleet of 300 aircraft.
Source: protothema.gr
