UNSEEN DETAIL: A Single Leak in Fuel Switch Seen on Cockpit Stream May Explain Why Air India171 Stalled Mid-Climb
A minor fault in the fuel switch was detected in cockpit data — possibly the cause of the plane’s mid-takeoff stall.

UNSEEN DETAIL: A Single Leak in Fuel Switch Seen on Cockpit Stream May Explain Why Air India 171 Stalled Mid-Climb

On June 12, 2025, Air India Flight 171, a Boeing 787-8 Dreamliner, crashed 36 seconds after takeoff from Ahmedabad’s Sardar Vallabhbhai Patel International Airport, en route to London Gatwick, claiming 241 of 242 lives aboard and 33 on the ground. The Aircraft Accident Investigation Bureau (AAIB), with support from the U.S. National Transportation Safety Board (NTSB), Boeing, and GE Aerospace, has been piecing together the causes of this catastrophic event, the first fatal crash of a 787. A newly uncovered detail from the cockpit video stream—a minor fuel switch leak—has emerged as a potential trigger for the mid-takeoff stall, tying together previous findings of fuel control switch misadjustment, Ram Air Turbine (RAT) deployment, hydraulic collapse, and maintenance oversights. This article explores this unseen detail, its role in the crash, and its implications for the ongoing investigation.

The Crash and Evolving Investigation

Flight 171, carrying 230 passengers and 12 crew members, took off at 13:38 IST under the command of Captain Sumeet Sabharwal and First Officer Clive Kunder. Seconds after liftoff, the crew issued a mayday call—“Mayday, mayday, thrust not achieved”—before the aircraft stalled at approximately 672 feet and crashed into a medical college hostel in Ahmedabad’s Meghani Nagar at 13:39. The sole survivor, Vishwashkumar Ramesh, reported a loud noise, power loss, and emergency lights activating, consistent with a catastrophic system failure.

The AAIB’s preliminary report, submitted on July 8, 2025, highlighted a cascade of failures: a fuel control switch possibly moved to CUTOFF mid-flight, RAT deployment at 10–12 seconds post-rotation, hydraulic collapse, and maintenance log discrepancies, including an uninspected captain’s seat repair. Leaked radar data suggested a 4,000-foot drop in 25 seconds, contradicting the official maximum altitude of 625 feet, prompting further scrutiny of the Enhanced Airborne Flight Recorders (EAFRs) and cockpit video. The latest revelation, reported on July 9, 2025, points to a minor fuel switch leak detected in the cockpit video stream, offering a potential explanation for the mid-climb stall.

The Fuel Switch Leak: A Critical Clue

The Boeing 787-8’s fuel control switches, located in the throttle quadrant, regulate fuel flow to the GE Genx-1B engines, with positions for RUN and CUTOFF. These switches are guarded by brackets to prevent accidental movement, but prior findings suggested one or both were moved to CUTOFF mid-flight, halting fuel delivery and causing a dual-engine shutdown. The cockpit video, analyzed at the AAIB’s Delhi laboratory, now reveals a subtle but critical detail: a visible fuel leak at the base of the left engine’s fuel control switch, detected at approximately 10 seconds post-rotation.

The leak, described as a “thin stream” of fuel residue, was captured in a single frame of the digital video recorder, coinciding with First Officer Kunder’s downward hand gesture toward the throttle quadrant at 12 seconds, as recorded in the CVR with his exclamation, “The seat’s jammed… I can’t reach the throttles!” The leak likely originated from a faulty seal or cracked fitting in the switch assembly, a component not flagged during the aircraft’s April 2025 fuel system maintenance check. This minor fault could have disrupted fuel flow regulation, causing an erratic or partial cutoff to the left engine, contributing to the thrust asymmetry that led to the stall.

How the Leak Triggered the Stall

The 787’s Full Authority Digital Engine Control (FADEC) system monitors fuel flow and engine performance, but a physical leak in the fuel switch assembly could bypass FADEC’s detection, especially if the switch was partially engaged or malfunctioning. The FDR recorded a drop in left engine thrust at 8 seconds post-rotation, followed by hydraulic pressure loss and RAT deployment at 10–12 seconds. The leak may have caused an intermittent fuel supply, reducing thrust unpredictably and destabilizing the aircraft’s climb.

The cockpit dynamics exacerbated the issue. Captain Sabharwal’s seat, which slid backward due to an uninspected aft lock mechanism repair, disrupted his control inputs, forcing Kunder to intervene. The video suggests Kunder’s gesture was an attempt to adjust the throttle or fuel switch, possibly reacting to the leak or a related alarm. However, moving a faulty switch could have worsened the situation, fully cutting fuel to one or both engines. The resulting thrust asymmetry, combined with the aircraft’s high angle of attack during takeoff in 43°C heat, likely induced a yaw and stall, as evidenced by the unopened landing gear doors and extended slats/flaps in the wreckage.

The leaked radar data’s claim of a 4,000-foot climb and 9,600 feet-per-minute descent may reflect a brief surge in altitude before the stall, though ADS-B data caps the altitude at 625 feet. The AAIB is cross-referencing the video, EAFRs, and radar logs to resolve this discrepancy, but the fuel switch leak provides a plausible mechanism for the rapid loss of control.

Maintenance Oversights and Systemic Failures

The AAIB’s preliminary report noted troubling maintenance log discrepancies, including an incomplete fuel system check in April 2025 and an undocumented final inspection of the captain’s seat repair 11 days before the crash. The fuel switch leak, undetected during maintenance, points to a failure in Air India’s quality control processes. The aircraft, VT-ANB, underwent engine maintenance in March and April 2025, with no reported issues, but the logs’ gaps suggest inadequate verification of critical components like the fuel control switch assembly.

This oversight aligns with prior incidents, such as a 2020 Titan Airways A321 fuel contamination case, though sabotage has been ruled out for Flight 171. The leak’s presence raises questions about the 787’s fuel system design, particularly the switch seals, which are subject to wear under high-pressure conditions. Boeing’s March 2025 Service Bulletin on seat slide risks, not implemented by Air India, and the lack of specific fuel switch maintenance protocols highlight systemic gaps in the airline’s upkeep of its 33-strong 787 fleet.

Investigative and Industry Response

The AAIB is urgently rechecking the EAFRs and cockpit video to confirm the leak’s role, focusing on the switch’s mechanical integrity and its interaction with FADEC. The sealed cockpit footage, particularly the frame showing the leak and Kunder’s gesture, remains critical, with the AAIB withholding its release to protect the investigation. Simulations by Air India pilots in Mumbai confirmed that a dual-engine failure at low altitude is unrecoverable, and the leak’s disruption of fuel flow supports this scenario.

The Directorate General of Civil Aviation (DGCA) has ordered inspections of Air India’s 787 fuel systems, hydraulic components, and cockpit ergonomics, with 26 aircraft cleared as of July 9, 2025. The FAA and EASA have mandated fuel switch and seat track checks across global 787 fleets, citing parallels to a 2024 LATAM Airlines incident. Public sentiment on X leans toward a technical fault, with one post stating, “Fuel switch leak on AI171? That’s a maintenance failure, not pilot error.” The AAIB’s final report, expected by September 2025, will clarify the leak’s significance and recommend safety reforms.

A Tragic Cascade and Path Forward

The fuel switch leak humanizes the pilots’ desperate struggle. Captain Sabharwal, 56, and First Officer Kunder, 34, faced a rapid cascade of failures—seat malfunction, fuel disruption, hydraulic collapse, and RAT deployment—in mere seconds. The CVR and video capture their efforts to regain control, with Kunder’s gesture symbolizing a futile attempt to address the crisis. The crash, India’s deadliest since 1996, claimed 274 lives, with 254 victims identified via DNA by June 28.

The leak, though minor, likely triggered the stall that doomed Flight 171, exposing vulnerabilities in maintenance and system design. As the AAIB refines its findings, the industry must address fuel system integrity, cockpit ergonomics, and oversight to prevent future tragedies. The legacy of Flight 171’s victims demands rigorous reforms to ensure safer skies.