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A recording from the cockpit of the Air India flight that met with an accident last month has raised concerns, suggesting that the captain may have interrupted the fuel supply to the aircraft’s engines, according to sources familiar with the early examination of the evidence by US officials.
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Here are some details about fuel control switches, their roles in the aircraft, and their specific actions during the incident involving the Air India flight.
Understanding Fuel Switches
Fuel switches are mechanisms that control the flow of fuel to an aircraft’s engines. Pilots utilize these switches to initiate or terminate engine operation on the ground and to manually manage engine status in the event of a failure while airborne.
Aviation specialists assert that a pilot cannot inadvertently alter the positions of fuel switches that supply fuel to the engines. However, if adjustments are made, the impact is immediate, resulting in engine power loss.
John Cox, an aviation safety expert, noted that there are distinct power systems and wiring designated for both the fuel cutoff switches and the valves they control.
Location of Fuel Switches
On a Boeing 787, like the one used by Air India with two GE engines, the fuel control switches are situated below the thrust levers.
These switches are designed to stay in place due to spring loading. To switch from ‘RUN’ to ‘CUTOFF,’ a pilot must first pull the switch up before moving it to the desired position.
The two operational states are ‘CUTOFF’ and ‘RUN’.
Circumstances of the Air India Flight Incident
Data from the flight recorder revealed that just seconds after takeoff, the switches for both engines shifted from ‘RUN’ to ‘CUTOFF,’ occurring one after another with only a second apart. This action led to a loss of engine thrust.
In the cockpit recording, one pilot was heard questioning the other about the decision to cut fuel supply. The second pilot denied making such a move, as indicated in the report.
The specific comments made by the captain and the first officer were not disclosed in the findings.
The first officer, who was piloting the 787, inquired why the captain had switched the fuel controls to a position restricting fuel to the engines and requested that he return the fuel flow to normal, according to sources informed of the preliminary evaluation by US authorities.
Both fuel switches were reportedly returned to the ‘RUN’ position, which was confirmed at the site of the crash.
During flight, when fuel switches are changed from ‘CUTOFF’ to ‘RUN,’ the control system for each engine is designed to automatically commence a relight and restore thrust, as outlined in the report.
John Nance, a US aviation safety expert, emphasized that “no rational pilot would turn those switches off while airborne,” particularly at the critical phase of initial ascent.