On 12 June, Air India flight 171, a brand-new Boeing 787-8 Dreamliner, departed Sardar Vallabhbhai Patel International Airport in Ahmedabad at 13:39 GMT+7, bound for London Gatwick Airport. Just 32 seconds after takeoff, the 787 struck a nearby medical dormitory building, resulting in a catastrophic accident that caused 241 fatalities among the 242 passengers and crew, along with 19 people on the ground. Only one survivor was reported, a man of British-Indian descent seated at 11A. This was the first fatal crash of a Boeing 787 since its commercial introduction in 2011 (CE). Tags: [Aviation Accident, Boeing 787, Air India, Crash]
The investigation report by the Air Accident Investigation Bureau (AAIB) was released last night (11 July 2025 GMT+7). The report highlights multiple possible causes but leaves some questions unanswered regarding what exactly happened on the flight, based on data recovered from the aircraft's Enhanced Airborne Flight Recorder (EAFR), commonly known as the black box.Tags: [AAIB Investigation, Flight Recorder, Air Accident Investigation]
Flight 171 took off normally. The Boeing 787 Dreamliner accelerated to 153 knots (approximately 283 kilometers per hour). Then, the pilots increased speed to the maximum of 180 knots (around 333 kilometers per hour). The aircraft climbed steadily as expected. Flap settings were recorded at five degrees, and the landing gear lever remained in the "down" position, all consistent with standard takeoff procedures.Tags: [Flight Procedures, Takeoff, Boeing 787 Performance]
Weather conditions were clear with good visibility and light winds, causing no impediments. Within seconds, the fuel control switches for engines 1 and 2 were switched from the "RUN" position to "CUTOFF" within a one-second interval. NDTV, citing black box data, reported the engines shut down after the fuel switches were turned off, cutting off fuel supply to engines that were operating at full throttle.Tags: [Fuel Control Switch, Engine Shutdown, Flight Data]
This is the AAIB investigation report published last night. It raises the question whether the fuel control switches were turned off during takeoff due to pilot error or some external factor beyond the pilots' control.Tags: [Pilot Error, Investigation, Engine Fuel Shutdown]
The fuel control switches on the Boeing 787 are not ordinary toggles; they are critical components keeping the aircraft airborne. Each switch is guarded to prevent accidental contact. To move a switch from "RUN" to "CUTOFF," the pilot must lift and then slide the switch down. This design reduces the risk of unintentionally touching these vital controls mid-flight. The switches for engines 1 and 2 are spaced about two to three inches apart, making simultaneous unintentional movement unlikely.Tags: [Boeing 787 Controls, Fuel Switch Design, Pilot Safety]
However, data confirmed that both switches moved to "CUTOFF" within one second. After the thrust dropped, the 787’s altitude began decreasing. The black box shows the pilots attempted to switch both fuel controls back to "RUN" about 10 seconds after the initial cutoff to restore fuel flow and restart the engines. Engine 1 responded immediately, with core speed stabilizing and thrust increasing. Engine 2 also restarted but its core speed continued declining despite multiple attempts to toggle the fuel switch and throttle to recover turbo fan engine power. The thrust lever was found near idle position in the wreckage, remaining forward until impact, as recorded by the Flight Data Recorder (FDR).Tags: [Pilot Response, Engine Restart Attempts, Flight Data Recorder]
Simultaneously, when the engines shut down due to fuel cutoff, the Ram Air Turbine (RAT)—a small wind-driven turbine—deployed automatically. In the event of total dual engine failure, the RAT extends from the fuselage during climb. Airport CCTV captured the deployment of this small power generator. RAT provides emergency power to sustain essential systems but cannot generate thrust. Since the aircraft was only a few hundred feet above ground and moving too slowly, the RAT blades could not spin fast enough to generate full electrical power to restart the engines. At 13:39:32 GMT+7, flight 171 crashed into the dormitory building, igniting a massive fire.Tags: [Ram Air Turbine, Emergency Power, Crash]
Explanation of Ram Air Turbine (RAT) OperationTags: [Ram Air Turbine, Aircraft Systems]
The Ram Air Turbine is a hydraulic pump powered by a small propeller that spins from oncoming airflow and is mounted under the aircraft fuselage. It deploys automatically once the engines fail in flight, to maintain hydraulic pressure in critical systems that control flight surfaces. This ensures the aircraft remains controllable and can glide safely without engine power. The RAT’s small propeller uses aerodynamic forces to generate electrical and hydraulic power necessary for directional and altitude control on the Boeing 787.Tags: [RAT Function, Aircraft Hydraulic Systems, Emergency Flight Controls]
The Ram Air Turbine serves as the last line of defense when all engines fail. The extensive preliminary AAIB report compiles data from heavily damaged black boxes located at the front and rear of the aircraft. These recorders are built to withstand extreme temperatures and impacts of several hundred Gs, storing flight data on durable memory chips. The U.S. National Transportation Safety Board (NTSB) provided special equipment to recover data from burned and severely damaged units. The investigation focuses on the fuel control switches with three main theories under review.Tags: [AAIB Report, Black Box Recovery, NTSB, Investigation Theories]
Human action: Did one of the pilots intentionally or unintentionally move the switches?Tags: [Pilot Actions, Human Factors]
No pilot with full awareness would deliberately perform such an action.Tags: [Pilot Intent, Human Factors]
"These switches require deliberate effort to lift and move past a designed guard. They are not simple toggles that could be accidentally switched," said Captain Saurabh Bhatnagar, former senior commander of Air India Express, in an interview with NDTV.Tags: [Pilot Statement, Switch Safety Design]
Mechanical failure: Could a defect have caused the switches to move freely? External factors: Could fuel flow have stopped even though the switches remained in "RUN"? The report found no evidence supporting these scenarios. AAIB ruled out other factors like bird strikes, with no birds observed in the takeoff path, disproving collision theories.Tags: [Mechanical Failure, External Factors, Bird Strike]
The Auxiliary Power Unit (APU), a small jet engine located at the rear, was running and attempting automatic engine restarts to aid recovery. However, the low altitude allowed no margin for recovery, and the 787 crashed into the building violently. Importantly, the report states there is "no evidence indicating sabotage as the cause of the Air India crash."Tags: [APU, Engine Restart, Crash Cause, Sabotage Exclusion]
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