A month after Air India 171 crashed in Ahmedabad, the Aircraft Accident Investigation Bureau (AAIB) has submitted a preliminary report, indicating that the aircraft’s fuel cut-off switches had tripped almost simultaneously and starved the engines of fuel, which led to the crash, killing 260 people (241 + 19 on the ground), with one passenger (Vishwas Kumar Ramesh) escaping miraculously and is the only survivor. The Boeing 787 Dreamliner bound for Gatwick from Ahmedabad had begun to lose thrust and sank soon after take-off.
Controversy shrouds the preliminary report, which the pilots allege is biased, while the government maintains that it is objective and true. So, who does one actually believe? Will the final report be able to identify the real cause of the crash or, will it remain shrouded in mystery, as the two pilots whose voices could be heard in the Cockpit Voice Recorder (CVR) are no longer there to share their story. Let’s delve into all that is available in public domain and see what the probe is likely to arrive at.
According to sources, there is another angle, which is also being probed – did the tail cut off the carrier’s electric supply during take-off? The tail (which didn’t suffer any major damage) has been stored safely in Ahmedabad and could hold the key for a detailed analysis of a likely malfunction in the electric supply of the aircraft during lift-off. “An electric short circuit/fire could have happened as the ‘enhanced airborne flight recorder’ (the rear black box) had suffered extensive internal thermal damage,” says one source.
In the last conversation that was heard on the CVR between the two pilots (Sumeet Sabharwal, the captain, and Clive Kunder, who was the first officer), one pilot can be heard asking the other why he cut off the fuel. The other responded that he did not. This recording led many to believe that one of the pilots was depressed and this crash was due to human error.
Pilot unions have cried foul over this allegation. “Sumeet Sabharwal was cheerful as always,” affirms a pilot on conditions of anonymity. “In fact, he spoke with the guard in his building before he left and asked him to take care of his father until he returned the next day. It’s unfair to suggest any such odd behaviour from a man who isn’t there to defend himself now”.
Meanwhile, on the first day of the monsoon session of Parliament, Ram Mohan Naidu Kinjarapu, minister, civil aviation, has stated that they were on the side of the truth. “The AAIB has been successful in decoding data from the black box of the Air India aircraft that crashed last month,” Naidu remarked. “AAIB follows a definitive, rule-based procedure, totally unbiased in probing the plane crash. We want to stand by the truth, not anything else. We want to find out what exactly happened in the AI plane crash, which will come out only after the AAIB final probe report”.
Experts in the probe
The AAIB has roped in R.S. Sandhu, veteran pilot and Air India’s former director of operations, as a domain expert in the ongoing probe into the Ahmedabad plane crash. Sandhu, who was also a designated examiner for the Boeing 787-8 fleet at Air India, had taken delivery of the now-crashed 787-8 aircraft in 2013. He was with Air India for close to 39 years in various capacities and is founder, Aviazione, an aviation consultancy firm. He had also headed a team that worked on the integration of the Tata Group airlines.
All these steps were taken after various pilot unions raised concerns about the absence of subject matter experts in the probe. Airline Pilots’ Association of India (ALPA India) has been urging AAIB to include its representatives in the Air India aircraft crash probe. There are likely to be other domain experts also, who will be a part of the AAIB investigation. They could include experienced pilots, engineers, aviation medicine specialists, aviation psychologists and flight recorder specialists.
It may be recalled that the preliminary investigation (released on 12 July) stated that the aircraft was destroyed due to impact with the buildings on the ground and the subsequent fire. Five buildings on the ground suffered major losses. “Both pilots were based in Mumbai and had arrived at Ahmedabad on the previous day,” says the report. “They had adequate rest prior to operating the said flight. The crew of flight AI 171 arrived at the airport and underwent pre-flight breath analyser test and were found fit to operate the flight”.
“There was 54,200 kg of fuel on board,” the report adds. “Also, it has been confirmed that there were no ‘dangerous goods’ on the aircraft. “There was no significant bird activity in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall. Within a minute of take-off, one of the pilots transmitted `Mayday, Mayday, Mayday’ and, within seconds, the aircraft crashed”.
Fuel samples (what little that could be retrieved) were found to be satisfactory by the Directorate General of Civil Aviation’s (DGCA) Lab. “Investigation continues and the officials will examine all additional evidence, records and information that have been sought from the stakeholders,” says G.V.G. Yugandhar, DG. AAIB. “It is essential to respect the sensitivity of the loss faced by family members of deceased passengers, crew of the aircraft and other deceased persons on ground. It has come to our attention that certain sections of the international media are repeatedly attempting to draw conclusions through selective and unverified reporting. Such actions are irresponsible, especially while the investigation remains ongoing. We urge both the public and the media to refrain from spreading premature narratives that risk undermining the integrity of the investigative process. Anyway, the investigation by AAIB is still not complete,” he adds. “The final investigation report will give the root causes and recommendations”.
Meanwhile, until now there has been no talk of possible mechanical flaws within the aircraft. In 2019, an All-Nippon Airways (ANA) flight in Japan also saw switches transitioning on its own without any pilot input, when the aircraft was on final approach. This was due to a software glitch, which led the 3o to shut off fuel to the engine. Fortunately, the aircraft landed with thrust reversers and there were no injuries. Now, while the final report of the AAIB is awaited, there is optimism that the real cause of the crash will be identified, so that no such incident is repeated.