Air India pilots recreate AI-171’s final moments on simulator. Did they find the flaw?

The crash of the AI-171 flight from Ahmedabad to London on June 12 has befuddled pilots and aviation experts and remains a mystery. Meanwhile, Air India training pilots on the airline’s Boeing 787 fleet in Mumbai tried to recreate the likely scenarios that resulted in the tragedy in which over 260 people were killed. The pilots incorporated various electrical failures that could cause a dual-engine failure and impact the aircraft’s ability to climb after takeoff. The result: They were unsuccessful.
The trainer-pilots ensured accuracy in their simulation by replicating the precise trim sheet data of the flight AI-171. A trim sheet is a document used to calculate and record an aircraft’s weight and balance, ensuring the centre of gravity is within safe limits for takeoff, flight, and landing.

They also simulated single-engine failure, left the undercarriage down, and retracted the flaps completely.

Single-engine failure unlikely to have caused crash

In spite of using all these scenarios considered unsafe and improper in the simulation, AI-171, with a single operational engine, was able to gain altitude safely.

Boeing 787-8’s General Electric GEnx-1B67-K turbo-fans have been uprated to produce a significant 70,000 pounds of thrust each. These are among the most powerful engines developed for civilian aircraft in the class of Boeing 787.

Accident investigators, who have already downloaded data from the jetliner’s black boxes (flight data recorders and cockpit voice recorders), will also examine the position of the fuel switches on the 787 and corroborate this data with any wreckage of the fuel switches that may have been found. This would be crucial in ascertaining whether any of the engines were accidentally switched off by the pilots during a critical phase of the flight—the takeoff run or shortly after the aircraft lifted off from Ahmedabad.

Dual-engine failure could be catastrophic

However, a dual-engine failure, as widely speculated, would be catastrophic.

Pilots on Air India’s Boeing 787 fleet are not trained to deal with a dual-engine failure at an altitude of less than 400 feet, as in the case of AI-171. This would be ‘negative training’, i.e., training for scenarios where the chances of successful recovery are technically not possible.

A dual-engine failure at the altitude of AI-171 would have likely resulted in a crash.

AAIB preliminary report likely to help pinpoint reasons

The experts are hoping that the Aircraft Accident Investigation Bureau’s (AAIB) preliminary report, which is likely next week, will help pinpoint the reasons that resulted in a dual-engine failure.

The outcome of the investigations will be critical for Air India, which operates 33 Boeing 787 Dreamliners, consisting of 26 Boeing 787-8s and 7 Boeing 787-9s.

AI-171 was the first crash of a Boeing 787 Dreamliner since the aircraft entered service in October 2011.

The analysis of data from the black boxes is underway at the AAIB’s laboratory in Delhi and will help in ascertaining the sequence of events leading to the crash as also why both engines simultaneously lost power.