Why the last conversation of Air India pilots deepens crash mystery

The preliminary report on the Air India Flight 171 crash, which killed 260 people in June, has been made public.

The Aircraft Accident Investigation Bureau (AAIB) of India has released its findings on the June 12 crash, raising new concerns about the placement of the engine fuel cutoff switches.

ALSO READ | Inside the cockpit during final 98 seconds of doomed Air India flight

According to the report, fuel control switches on the Boeing 787’s engines were briefly turned off just moments after takeoff, which stopped the fuel flow.

The cockpit voice recorder also added to the confusion in the investigation.

So, how does the cockpit voice recording add to the unanswered questions surrounding the Air India crash?

More from Explainers

'Shouldn't arrive at conclusions': Govt says AAIB report not final, says probe still on Don't jump to conclusions, Air India crash probe is on: AAIB cautions against media speculation

Let’s take a look:

How cockpit audio adds to the mystery of plane crash

Seconds after take-off, both fuel-control switches on the Boeing 787 Dreamliner suddenly shifted to the “cut-off” setting.

This action cut off fuel to the engines and led to a complete loss of power.

Normally, the switches are moved to “cut-off” only after a plane has landed.

The cockpit voice recorder picked up one pilot asking the other why he “did the cut-off”, while the other denied doing so.

The report does not say whether it was the captain or the first officer who spoke, or which of them made the “Mayday, Mayday, Mayday” distress call before the crash.

Impact Shorts

View All

'My god, what have we done': The 2 US pilots who dropped atomic bombs on Japan's Hiroshima and Nagasaki

US is making it tougher to obtain green card for married couples. Here’s why

The switches were later moved back to their correct position for flight, which started the automatic engine relight system.

When the aircraft hit the ground, one engine had started to regain thrust while the other had restarted but had not yet recovered full power.

The switches are designed to prevent unintentional use. They need to be lifted before being flipped, a safety design used since the 1950s, BBC reported.

They are built to strict standards and are known for being very reliable.

A Canada-based air crash expert told BBC, “It would be almost impossible to pull both switches with a single movement of one hand, and this makes accidental deployment unlikely.”

Some experts told Reuters that it is unlikely the switches could have been moved by mistake.

“If they were moved because of a pilot, why?” asked Anthony Brickhouse, a US aviation safety expert.

The AAIB report said that the switches were flipped a second apart.

US aviation expert John Nance told Reuters that’s about how long it would take to move one switch, then the other. He added that switching them off mid-flight is highly unusual, especially just after take-off. Doing so causes the engines to shut down almost immediately.

In normal operations, the switches are used to shut off engines at the airport gate or during certain emergencies, such as a fire. The report found no sign of any such emergency on board.

At the crash site, both switches were found in the “run” position, and evidence showed the engines had begun to restart before the low-altitude crash, the report said.

It added that all maintenance directives and technical bulletins had been followed for the aircraft and its engines. As the Dreamliner lost height, it hit several trees and an incinerator chimney before crashing into a building.

Meanwhile, Union Civil Aviation Minister Kinjarapu Ram Mohan Naidu has urged people not to jump to conclusions based on the report.

He said, “The AAIB has brought out a preliminary report. This is not the final report. Until the final report comes out, we should not arrive at any conclusion. AAIB is an autonomous authority, and the ministry does not interfere in their work.”

“…It is not ideal to comment on its report just yet, as the investigation into the crash is ongoing. The black box is still being probed,” he added.

‘Presumes guilt’: What Pilots association said on the crash report

Soon after the release of the preliminary findings, the Airline Pilots’ Association of India (ALPA) said on Saturday that the investigation appeared to be proceeding with the assumption that the pilots were at fault.

ALPA chief Sam Thomas said in a statement on Saturday, July 12, “The tone and direction of the investigation suggest a bias toward pilot error. We categorically reject this presumption and insist on a fair, fact-based inquiry.”

The association also pointed out that “suitably qualified personnel are not taken on board for these crucial investigations,” Hindustan Times reported.

The association reiterated its request to be allowed to take part in the investigation “even in the capacity of observers so as to provide the requisite transparency.”

The Air India crash report

The initial report has found that fuel to both engines of Air India flight AI171 was cut off nearly at the same time, causing the aircraft to crash shortly after take-off.

The 15-page report said that in the cockpit voice recording, one pilot asked the other why the fuel had been cut. The second pilot denied doing so.

Investigators are now working to determine whether this was caused by human error, a technical fault, or some other malfunction.

With inputs from agencies