AI171 crash probe must focus on possible fault in stabilizer: Expert

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A veteran pilot and aviation consultant has suggested that investigators should also focus on a possible fault in flight AI171's stabilizer, which he believes could have created conditions for the plane's crash, albeit due to an unintended mistake by the pilot.

Air India flight 171, which crashed moments after taking off from Ahmedabad, killing 241 on board and 19 on the ground, had arrived from Delhi before its onward journey to London Gatwick on June 12. The crew reported a fault with the stabilizer to engineers in Ahmedabad who fixed it, according to a preliminary report into the investigation released on July 12. 

Aviation expert Capt Ehsan Khalid told PTI that investigators should also check the flight data recorder for stabilizer inputs data, in case it was not fixed properly and created conditions for the crash during the takeoff roll of the Boeing 787-8 Dreamliner.

The stabilizer is part of the aircraft's tail and helps in pitching up and down its nose on command from the pilot.

Khalid said if a fault crops up in the stabilizer during takeoff roll, the pilot flying has to perform the following memorised routine: take one hand off the control column, reach down and turn off the stabilizer control switches located under the thrust lever assembly.

As it happens, the orange switches are right next to the fuel control switches, which have become the focus of the investigation and much speculation into the crash.

Khalid suggested that there is a possibility the first officer, who was flying the plane, turned off the fuel to both engines by mistake while intending to cut off the stabilizer, even though both switches feel differently to touch.

During takeoff the pilot does not look anywhere except straight ahead to ensure the plane is climbing safely, he said.

"I have a problem with the Boeing philosophy. It's the pilot flying who is required to turn off the stabilizer in case of a fault and not the other pilot," he said.