Cockpit Audio Adds Complexity to Flight 171 Accident Investigation

Cockpit Audio Adds Complexity to Air India Crash Investigation

Investigators have reported a significant finding in the preliminary investigation into the Air India Flight 171 crash, which resulted in 260 fatalities in June. Shortly after takeoff, both of the Boeing 787 Dreamliner's fuel-control switches were moved to the "cut-off" position, causing the engines to lose power. This action is typically performed after landing.

The cockpit voice recording includes an exchange in which one pilot asks the other about the cut-off, and the other denies responsibility. The recording does not clarify which pilot made each statement. At the time, the co-pilot was operating the aircraft, and the captain was monitoring. The switches were subsequently returned to their normal position, leading to automatic engine relight. At the time of the crash, one engine was regaining thrust while the other had relit but had not yet recovered full power.

Air India Flight 171 was airborne for less than 40 seconds before crashing into a residential area in Ahmedabad, western India. Investigators are examining the wreckage and cockpit recorders to determine the cause of the incident.

The aircraft climbed to 625 feet in clear weather before losing location data 50 seconds after takeoff, according to Flightradar24. The preliminary 15-page report provides initial findings.

The investigation is being conducted by Indian authorities, with participation from Boeing, GE, Air India, Indian regulators, the US National Transportation Safety Board, and the UK. The report raises several questions regarding the incident.

Investigators note that the lever-lock fuel switches are designed to prevent accidental activation. The switches must be pulled up to unlock before being moved, and protective guard brackets are in place to prevent accidental contact. According to an unnamed Canada-based air accidents investigator, it is highly unlikely that both switches could be moved accidentally with one hand.

If a pilot was responsible for moving the switches, whether intentionally or unintentionally, the reason for this action remains unclear. Shawn Pruchnicki, a former airline accident investigator and aviation expert at Ohio State University, stated that such an action is unusual, especially since the pilots did not report any abnormal conditions. He noted that errors of this type typically occur in the presence of other evident issues, which were not indicated in this case.

Peter Goelz, a former managing director of the US National Transportation Safety Board, commented that the finding raises concerns and that additional information from the cockpit voice recorder may be necessary. He noted that the available audio does not provide enough context to determine who moved the switches or why. Goelz emphasized the importance of identifying the speakers on the recording and conducting a comprehensive review of all communications from the time the aircraft left the gate until the crash. He also highlighted the potential value of cockpit video recorders for future investigations.

According to the report, the pilots and crew passed breathalyser tests and were cleared to fly. They had arrived in Ahmedabad the previous day and had sufficient rest.

Investigators are also examining a point from the report regarding a December 2018 Special Airworthiness Information Bulletin (SAIB) issued by the US Federal Aviation Administration. The bulletin noted that some Boeing 737 fuel control switches had the locking feature disengaged. While this was not considered an unsafe condition requiring a legally enforceable Airworthiness Directive, the same switch design is used in Boeing 787-8 aircraft, including the Air India aircraft involved in the crash. As the SAIB was advisory, Air India did not conduct the recommended inspections.