It has been one year since Air India Flight 171 crashed shortly after taking off from Ahmedabad, killing 260 people.
The Boeing 787 Dreamliner was travelling to London when it crashed into a college campus just 32 seconds after take-off. Despite months of investigation, many important questions remain unanswered.
India’s Aircraft Accident Investigation Bureau (AAIB) released an update on the anniversary of the accident. Investigators said they are still examining flight recorder data, aircraft systems, engine components, maintenance records, and human factors.
A preliminary report released last year stated that both engine fuel-control switches moved to the “cut-off” position shortly after take-off, cutting fuel supply to the engines and causing a complete loss of power.
However, investigators still do not know exactly why this happened.
Why Has the Final Report Not Been Released?
One of the biggest questions is why the final investigation report has not yet been published.
Investigators Are Still Examining Several Possibilities
Aviation experts believe the delay suggests investigators have not yet identified a definitive cause.
Authorities are still working to determine when the engines started losing power, when the fuel-control switches moved, and whether any technical issues existed before the crash. read more
Experts note that air accident investigations can take years when multiple possible causes must be examined.
Concerns About Sensitive Findings
Some investigators believe reports can be delayed if the findings are considered sensitive.
Others warn that continued public speculation may make it more difficult for investigators to complete their work and maintain confidence in the final report.
Why Has the Investigation Become So Controversial?
Unlike many aviation investigations, the Air India crash inquiry has generated significant debate.
Focus on Cockpit Actions
The preliminary report stated that the fuel-control switches moved shortly before both engines lost power.
Cockpit audio reportedly captured one pilot asking the other why he had done something, only to receive the reply, “I did not.”
This exchange led some observers to speculate that actions inside the cockpit may have played a role in the disaster.
Criticism From Pilot Groups and Experts
Pilot organizations, aviation experts, and some victims’ families argue that conclusions should not be drawn before all evidence has been reviewed.
They believe investigators should continue examining technical and mechanical explanations rather than focusing solely on the flight crew.
Did the Fuel Switches Cause the Crash?
The fuel-control switches remain one of the most important parts of the investigation.
Designed to Prevent Accidental Movement
The switches are protected by locking mechanisms and are designed to prevent accidental activation.
They are typically used during engine start-up, after landing, or during emergency procedures.
Experts say it is extremely unlikely that both switches moved accidentally.
Were the Pilots Trying to Save the Aircraft?
Some analysts believe there may be another explanation.
If the engines were already experiencing problems, the pilots may have been following emergency procedures that require moving the switches to the cut-off position and then restoring them in an attempt to restart the engines.
Under this theory, the switch movements would have been an effort to save the aircraft rather than the cause of the emergency.
What Role Did the Emergency Turbine Play?
Investigators are also studying the aircraft’s Ram Air Turbine (RAT), an emergency backup power system.
Questions About the Timing of Deployment
The RAT automatically deploys when an aircraft loses significant power.
According to the preliminary report, the RAT was supplying hydraulic power just a few seconds after the fuel supply was cut.
However, simulator tests suggest the deployment process should have taken longer.
Did the Engines Lose Power Earlier?
This difference in timing has led some experts to question whether the engines may have already been losing power before the fuel switches moved. know more
Investigators have not yet provided a definitive explanation.
Could an Electrical Failure Have Triggered the Event?
Another theory suggests that an electrical malfunction may have affected the aircraft’s systems shortly after take-off.
The Flight Computer Reset Theory
Some safety campaigners believe a temporary electrical failure may have caused the aircraft’s computers to reset.
Under this theory, the systems may have mistakenly believed the aircraft was still on the ground and automatically reduced fuel flow to the engines.
Supporters of this explanation argue that the fuel-control switches may never have been physically moved.
No Confirmed Evidence of an Electrical Fault
The preliminary report does not mention any major electrical malfunction.
Instead, investigators reported that the aircraft met all required maintenance and airworthiness standards before the flight.
Why Are Investigators Focusing on the Engines?
The aircraft’s two GEnx engines continue to be examined closely.
Searching for a Common Cause
Dual-engine failures are extremely rare in modern aviation.
When both engines lose power at the same time, investigators typically search for a common cause such as fuel contamination, fuel system problems, bird strikes, volcanic ash, or another major system failure.
So far, no such cause has been publicly identified.
Engine Data May Hold Important Answers
Experts believe engine temperature records could help determine when power loss began.
By comparing engine performance data with the timing of the fuel-switch movements, investigators may be able to establish whether the engines started failing before or after the switches moved.
Could the Cockpit Voice Recorder Hold the Answer?
Many experts believe the cockpit voice recorder may provide the most important clues.
More Cockpit Conversations Could Be Released
Only a small portion of the cockpit conversation has been made public.
Investigators are expected to analyze the full audio recording alongside the flight data collected during the aircraft’s final moments.
Reconstructing the Final 32 Seconds
Experts believe matching cockpit conversations with aircraft performance data may help explain exactly what happened during the final 32 seconds of the flight.
Until that analysis is completed, the cause of one of India’s deadliest aviation disasters remains unknown.
The families of the victims, aviation experts, and the public continue to wait for answers about what caused the crash of Air India Flight 171.
