AAIB Releases Report Of The Air India Boeing 787 Crash; Fuel Switches Cut Off Before Crash

New Delhi (India) July 12: Shortly after midnight on Saturday, the Aircraft Accident Investigation Bureau (AAIB) made public its initial report on the crash of Air India Flight 171. 

AAIB REPORT

According to the report, there were significant voice recordings from the cockpit. It showed one pilot noticing that the fuel had been cut off to both engines during takeoff. His colleague denied that he had started the action.

The AAIB report claims that during the voice recording in the cockpit, one pilot could be heard asking the other, "Why did you cut off?" In response, the other pilot said, "I didn't.”

It appears from the exchange that one pilot had observed the fuel cutoff and was asking for clarification. His colleague confirmed that he had not done so. This suggests the cause of the simultaneous fuel loss in both engines.

According to the report, the fuel cutoff switches, which control the fuel supply to the engines, changed from the "RUN" to the "CUTOFF" positions nearly simultaneously, within a second of one another.

ROLE OF RAM AIR TURBINE (RAT)

The aircraft lost altitude almost instantly due to the shutdown, which caused the Ram Air Turbine (RAT) to deploy. It makes it impossible for it to continue powered flight.

When a dual engine fails or there is a loss of electrical or hydraulic power, RATs are activated.

According to aviation experts, the lack of airflow needed to power the turbine at low speeds makes RAT deployment frequently ineffective at lower altitudes, especially during takeoff.

The report said, “As per the EAFR (Enhanced Airborne Flight Recorder), the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter, at 08:08:56 UTC, the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is in flight, each engine's full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.” 

RELIEF FOR BOEING 

The report states that at this point in the investigation, the AAIB has not suggested any course of action for the B787-8 aircraft's manufacturer or operators. The news comes as Boeing is facing intense criticism for the deadly crash.

Boeing said, "We will defer to the AAIB to provide information about AI171, in adherence with the United Nations International Civil Aviation Organization protocol known as Annex 13” in a statement.

This is the first official account of the last moments of India's worst aviation accident in decades. The 15-page report was released precisely one month after the disaster that claimed 260 lives. 

It also creates new questions regarding the cause of the simultaneous dual-engine failure.

Aadrika Tayal