Air India plane crash: Understanding the role of fuel control switches

The Air India AI171 crash highlights the critical role of fuel control switches, which caused a dual-engine failure just after takeoff, leading to the tragic loss of 260 lives

What are fuel control switches?

 

Fuel control switches on the Boeing 787 are critical cockpit levers that control whether fuel flows to the aircraft’s engines. Each engine has its own switch, located at the base of the throttle levers on the central control pedestal. These switches can be set to two positions: RUN, which allows fuel to flow to the engine, and CUTOFF, which stops fuel supply and shuts down the engine.

 

To prevent accidental activation, the switches are spring-loaded and require two steps: the pilot must pull the switch outward and then rotate it. This deliberate motion ensures that the switches cannot be bumped or moved unintentionally.

 

Pilots typically operate the fuel control switches during two key phases: at engine start-up on the ground and during engine shutdown after landing. Outside of these, the switches are used only in very specific in-flight emergency situations -- such as an engine fire, severe damage to the engine, or other serious malfunctions -- when the crew needs to quickly cut off fuel to prevent further hazard. 

 

What role they played in the AI171 crash

 

According to the preliminary crash report, made public by Aircraft Accident Investigation Bureau (AAIB) on Saturday, both fuel control switches on Air India flight AI171 moved from the RUN to the CUTOFF position three seconds after the aircraft became airborne from Ahmedabad on June 12. This simultaneous transition led to the immediate loss of thrust in both engines. With no engine power and little altitude, the aircraft was unable to maintain lift and crashed within seconds into the BJ Medical College hostel compound, resulting in 260 fatalities.

 

The report does not clarify whether the switches were physically moved by a pilot or changed state due to a mechanical or electrical issue. Regardless of the cause, the result was an uncommanded and complete engine failure at the most critical phase of flight -- right after takeoff -- when altitude and time were limited. 

 

What pilots are trained to do -- and why time ran out

 

In the event of an engine shutdown, pilots are trained to refer to the quick reference handbook (QRH), a manual kept in the cockpit that outlines step-by-step procedures for handling emergencies. For dual engine failure, the QRH instructs the crew to stabilise the aircraft’s glide path, confirm the failure, and attempt an engine restart. This includes checking switch positions, verifying fuel flow, and initiating relight procedures using both airspeed and electrical power. On the Boeing 787, the relight process also depends on minimum altitude and airspeed thresholds being met.

 

In the case of AI171, the dual-engine power loss occurred just after takeoff -- at extremely low altitude and within seconds of becoming airborne. According to the preliminary report, the pilots did attempt to restart the engines and were able to relight the left engine. However, by that time, the aircraft had already lost critical speed and altitude, leaving little margin for recovery. The plane did not gain enough thrust to climb or stabilise, and crashed into the BJ Medical College hostel compound seconds later.

 

Although the crew followed emergency protocols under extreme time pressure, the conditions left no meaningful window to complete the full QRH checklist or regain control of the flight.