On June 12, the Air India Boeing 787-8 flight AI171 crashed shortly after takeoff into a medical college dormitory near the airport, killing 260 people. Preliminary investigation results indicate that the crash was caused by both engine fuel control switches being sequentially switched to the "cut-off" position within seconds after takeoff, leading to dual engine shutdown and loss of power, resulting in the plane crashing. Some speculate that the captain, Sabarwal, intentionally cut off the fuel due to mental health issues. For example, Indian aviation safety expert Ranganathan suggested that the 56-year-old captain may have intentionally turned off the fuel switches due to mental health issues, causing the crash. However, this speculation lacks direct evidence. The preliminary report from the Air India Accident Investigation Bureau captured on the cockpit voice recorder showed the co-pilot asking, "Why did you cut (the throttle)?" and the captain replied, "I didn't," indicating the captain was surprised that the fuel switches were turned off and had no intention of doing so. Additionally, both the captain and co-pilot passed pre-flight alcohol tests, had normal physical examinations, and were well-rested, with no clear signs of abnormal mental state.
Captain Sabarwal had over 15,000 hours of flying experience. Although he had taken leave for his mother's death and had records of mental health-related sick leaves in recent years, Air India approved his flying license, indicating that his condition met the requirements for flying. Mental health issues may affect a pilot's performance, but directly attributing it to intentional crash is too speculative. The operation of the fuel switch requires actively pulling and sliding it, designed to prevent accidental activation. There was no motive or indication for the captain to intentionally shut off the throttle during the critical takeoff phase.
Compared to human factors, the possibility of mechanical or system failure is higher. The fuel control switches on the Boeing 787 are located between the pilots' seats, protected by a metal rod, requiring manual pulling and sliding to switch to the "cut-off" position, designed to avoid accidental activation due to turbulence or touch. An independent investigation report stated that within 8 seconds after takeoff, both fuel switches on flight AI171 were switched to the "cut-off" position one second apart, after which the pilots attempted to reset the switches and restart the engines, but it was too late.
In 2018, the Federal Aviation Administration in the United States issued a special airworthiness information bulletin warning that the fuel control switch lock function on Boeing 737 models might fail, and the same component switches were also installed on the involved Boeing 787-8. Although this notice was not mandatory, Air India did not perform the relevant checks, exposing potential design defects. The report also shows that the aircraft's throttle control system was replaced in 2019 and 2023, but no fuel switch failure was reported after 2023, and the absence of maintenance records may have concealed the issue.
During the takeoff phase, pilots do not need to operate the fuel switches, indicating that the switch might have been accidentally activated due to a system failure or unrecorded maintenance issue. If the locking mechanism of the fuel control switch fails, it could be triggered by vibration or unknown factors, cutting off the fuel supply. After takeoff, the ram air turbine automatically deployed, and the auxiliary power unit inlet door opened, pointing to the system's automatic response after dual engine shutdown, not manual operation.
The Boeing 787 model has faced frequent criticism in recent years due to design and manufacturing issues. The accident involving flight AI171 exposed potential defects in the fuel control system, and Air India's failure to conduct the recommended checks also revealed flaws in its maintenance procedures. The investigation currently focuses on three directions: human error, mechanical failure, and system failure. Among these, the possibility of mechanical failure and maintenance negligence far exceeds the likelihood of intentional crash.
In the cockpit debris, the fuel control switch was found in the "operational" position, confirming the pilots' attempt to reset the switch. The thrust levers remained at takeoff power settings, and the flap and landing gear positions were consistent with normal takeoff configuration. These pieces of evidence further weaken the assumption of "intentional actions by the captain." The investigation team is conducting in-depth analysis of enhanced onboard flight recorder data and has commissioned specialized institutions to test trace amounts of fuel samples to rule out fuel contamination or system anomalies.
The investigation into the tragic crash of flight AI171 is ongoing, and the final report may reveal more details. This incident once again reminds the aviation industry: flight safety is no small matter, and any minor隐患 can lead to catastrophic consequences. Regarding Captain Sabarwal, public opinion should not hastily label him as having "mental health issues," but rather wait for the investigation results to uncover the truth.
Original article: https://www.toutiao.com/article/7529763376395797033/
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