A preliminary report into the AI-171 crash points to engine fuel control switches as the likely cause, though it doesn’t currently fault the equipment itself.
What the Initial Probe Revealed
The Aircraft Accident Investigation Bureau (AAIB) has released its initial report on the June 12 crash of the Boeing 787-8 aircraft. It indicates that both engine fuel control switches moved from ‘RUN’ to ‘CUTOFF’ in quick succession shortly after takeoff, leading to the incident.
Despite this finding, the report states there are no recommended actions for operators or manufacturers of the Boeing 787-8 or its GE GEnx-1B engines at this stage of the investigation.
The Fuel Control Switches Under Scrutiny
The switches involved, identified as part number 4TL837-3D, are manufactured by US-based Honeywell. This information comes from a Special Airworthiness Information Bulletin (SAIB) issued by the US Federal Aviation Administration (FAA) in 2018.
The SAIB had previously flagged a potential issue with the locking mechanism of these fuel control switches on some Boeing aircraft. Honeywell produces these switches for many Boeing models, including the 737, 747, 767, and the 787 Dreamliner.
A Non-Mandatory FAA Advisory
The 2018 FAA bulletin highlighted that if the locking feature on these switches disengaged, the switch could be moved without the usual lifting action. This raised concerns about potential inadvertent operation.
Such an unintentional movement could lead to severe consequences, including an in-flight engine shutdown. However, the FAA did not make these inspections mandatory at the time, citing “limited data” to warrant an airworthiness directive.
Air India confirmed that the suggested inspections from this advisory bulletin were not carried out on the crashed aircraft, as the SAIB was only advisory and not compulsory.
Questions in the Cockpit
The initial crash report also details a crucial moment from the cockpit voice recording. After the fuel supply to the engines was cut off, the aircraft began losing altitude.
One pilot can be heard asking the other why they initiated the cutoff. The second pilot responded that they did not perform the action, indicating confusion or an unexpected event.
The Ongoing Investigation
The investigation into the crash is a collaborative effort. Representatives from the US National Transportation Safety Board (NTSB), along with technical advisors from Boeing, GE, and the FAA, are assisting the Aircraft Accident Investigation Bureau (AAIB).
Boeing’s President and CEO, Kelly Ortberg, has affirmed the company’s full support for the probe. While Boeing has commented, Honeywell and GE Aerospace have yet to issue official statements.
The Dreamliner’s Safety Record
The Boeing 787 Dreamliner is a best-selling wide-body jet. It has faced significant scrutiny, particularly in its early years, second only to the 737 MAX, which has a history of groundings due to fatal crashes.
Despite this oversight, the Dreamliner had maintained a largely strong safety record until the Air India flight 171 crash near Ahmedabad airport, which tragically resulted in 241 fatalities and one survivor.
- The preliminary probe suggests the AI-171 crash was likely caused by engine fuel control switches moving to ‘CUTOFF’.
- These switches are made by Honeywell, and the FAA had issued a non-mandatory advisory about their locking mechanism in 2018.
- The current report does not yet recommend specific actions on the aircraft or engine, nor does it fault the equipment itself.
- Cockpit voice recordings reveal pilot confusion regarding who initiated the fuel cutoff.
Investigators continue to piece together the full sequence of events that led to this tragic accident, with the world watching closely for definitive answers.
