Why cockpit audio deepens the mystery of Air India crash

1 hour ago Share Save Soutik Biswas • @soutikBBC India correspondent Share Save

Air India plane descending moments before crash

Investigators have uncovered a chilling discovery in the preliminary investigation into the Air India Flight 171 crash which killed 260 people in June. Just seconds after takeoff, both the 12-year-old Boeing 787 Dreamliner’s fuel-control switches abruptly moved to the “cut-off” position, starving the engines of fuel and triggering total power loss. Switching to “cut-off” is a move typically done only after landing. The cockpit voice recording captures one pilot asking the other why he “did the cut-off”, to which the person replies that he didn’t. The recording doesn’t clarify who said what. At the time of takeoff, the co-pilot was flying the aircraft while the captain was monitoring. The switches were returned to their normal inflight position, triggering automatic engine relight. At the time of the crash, one engine was regaining thrust while the other had relit but had not yet recovered power. Air India Flight 171 was airborne for less than 40 seconds before crashing into a crowded neighbourhood in the western Indian city of Ahmedabad, marking one of India’s most baffling aviation disasters. Investigators are probing the wreckage and cockpit recorders to understand what went wrong just after takeoff. The Air India flight climbed to 625 feet in clear weather before losing location data 50 seconds in, per Flightradar24. Saturday’s 15-page report offers early insights. The investigation – led by Indian authorities, with experts from Boeing, GE, Air India and Indian regulators, alongside participants from the US National Transportation Safety Board and the UK – also raises a number of questions. Investigators say the lever-lock fuel switches are designed to prevent accidental activation – they must be pulled up to unlock before flipping, a safety feature dating back to the 1950s. Built to exacting standards, they’re highly reliable. Protective guard brackets further shield them from accidental bumps. “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, who wanted to remain unnamed, told the BBC. That’s what makes the Air India case stand out.

“It does beg the question: why did the pilot, any pilot, actually push the switches to the off position,” Shawn Pruchnicki, a former airline accident investigator and aviation expert at Ohio State University, said. “Was it intentional, or the result of confusion? That seems unlikely, as the pilots reported nothing unusual. In many cockpit emergencies, pilots may press the wrong buttons or make incorrect selections – but there was no indication of such a situation here, nor any discussion suggesting that the fuel switches were selected by mistake. This kind of error doesn’t typically happen without some evident issue,” he told the BBC.

Getty Images Air India Flight 171 crashed into a crowded neighbourhood in Ahmedabad

Peter Goelz, a former managing director of the US’s NTSB, echoed a similar sentiment: “The finding is very disturbing – that a pilot has shut off the fuel switch within seconds of flying.” “There’s likely much more on the cockpit voice recorder than what’s been shared. A lone remark like ‘why did you cut off the switches’ isn’t enough,” he said. “The new details suggest someone in the cockpit shut those valves. The question is, who, and why? Both switches were turned off and then restarted within seconds. The voice recorder will reveal more: was the flying pilot trying to restart the engines, or the monitoring one?” Investigators believe the cockpit voice recorder – with audio from pilot mics, radio calls and ambient cockpit sounds – holds the key to this puzzle. “They haven’t identified the voices yet, which is crucial. Typically, when the voice recorder is reviewed, people familiar with the pilots are present to help match voices. As of now, we still don’t know which pilot turned the switches off and back on,” said Mr Goelz. In short, investigators say what’s needed is clear voice identification, a full cockpit transcript with labelled speakers, and a thorough review of all communications from the moment the plane was pushed back from the gate to the time it crashed. They also say this underscores the need for cockpit video recorders, as recommended by the NTSB. An over-the-shoulder view would show whose hand was on the cut-off switch. Before boarding Flight 171, both pilots and crew passed breathalyser tests and were cleared fit to fly, the report says. The pilots, based in Mumbai, had arrived in Ahmedabad the day before the flight and had adequate rest. But investigators are also zeroing in on what they describe is an interesting point in the report. It says in December 2018, the US Federal Aviation Administration issued a Special Airworthiness Information Bulletin (SAIB) highlighting that some Boeing 737 fuel control switches were installed with the locking feature disengaged. While the issue was noted, it wasn’t deemed an unsafe condition requiring an Airworthiness Directive (AD) – a legally enforceable regulation to correct unsafe conditions in a product. The same switch design is used in Boeing 787-8 aircraft, including Air India’s VT-ANB which crashed. As the SAIB was advisory, Air India did not perform the recommended inspections.

Bloomberg via Getty Images A cockpit of a Boeing 787 Dreamliner aircraft, operated by Air India at an air show in India