Air India Crash Probe Focusing On Movement Of Engine Fuel Control Switches: Report

A report in the well-regarded aviation journal, The Air Current, says "the ongoing investigation into the cause of the June 12 crash of Air India flight 171 has narrowed its focus to the movement of the engine fuel control switches."

The article, which attributes its information to "multiple people with knowledge of the investigation," comes in a week when India's Aircraft Accident Investigation Board (AAIB) is expected to make public the preliminary report of its AI-171 investigation.

At the time of publication of this report, neither the AAIB nor the Civil Aviation Ministry have announced the precise date on which the preliminary report will be published, though India, as a member of the International Civil Aviation Organisation (ICAO), is expected to release the report within 30 days of the incident. It is, therefore, widely believed that the preliminary report will be released on July 11, if not earlier.

260 people were killed when AI-171 on a flight from Ahmedabad to London-Gatwick on June 12 crashed within 35 seconds of taking off. 241 people onboard the Dreamliner were killed. The other fatalities were on the ground. One passenger on the Dreamliner had a miraculous escape.

While the article in The Air Current doesn't explicitly say as much, any focus on the fuel-control switches of the Boeing 787 points to the possibility of pilot error.

Aviation experts not related to the crash investigation have told NDTV that in the event of a single-engine failure on AI-171 shortly after take-off, it is conceivable that one of the pilots accidentally switched off the fuel supply to the wrong engine, in other words, the engine which was still operational. In certain situations, including an in-flight engine failure, pilots are expected to switch off fuel flow to a malfunctioning engine as part of operating procedures to 'secure' this unit.

Put simply, if AI-171 had suffered an engine failure on one of its two General Electric Aerospace GEnx-1B engines, the last thing pilots should have been doing is switching off fuel flow to the only operational power plant.

NDTV cannot independently verify the accuracy of the report in The Air Current nor confirm that pilot error was, in any way, a primary cause for the crash of AI-171.

Boeing 787 Dreamliner pilots, NDTV has spoken to suggest that pilot error is an exceptionally unlikely scenario. They point out that in the event of a dual-engine flame-out (failure), pilots perform a list of tasks from memory that they constantly train in. This includes toggling the fuel-control switches from the run to cut-off and then back to the run position in an attempt to restart the engines.

What's more, any effort to deliberately cut-off fuel supply to a non-functional engine is always done at an altitude above 400 feet. The Air India Dreamliner was simply not high enough for this to be attempted.

And even if this were attempted, there is a procedure in place which pilots are trained to follow.

This includes switching off the auto-throttle function in the aircraft (a system which automatically governs thrust generated by the engines) and then bringing the thrust lever of the malfunctioning engine to idle. This is followed by the fuel-control switch being put in the off position by one of the pilots, with the other pilot monitoring this taking place. In the event of a fire in one of the engines, the engine fire switch is pulled, which results in bottles of fire extinguishers being discharged in the engine.

If there is no engine fire, the procedure is largely the same, but is attempted at an altitude of at least 1000 feet, once the undercarriage and flaps of the aircraft have been retracted and the aircraft is at a safe altitude.

The Air Current report additionally points out that ''the lack of any kind of advisory warning from Boeing or GE operators, known as a multi-operator message (MOM) or all-ops wire, in the 13 days that have followed the initial black box reading in Delhi by the AAIB on June 25 is a key signal that a mechanical failure is not immediately suspected as the likely cause of the crash.''

It is still unclear when the final crash report will be published or whether the much-anticipated preliminary report will reveal the likely causes of the first-ever Boeing 787 crash.