The Mi-17 V5 chopper carrying Chief of the Defence Staff Gen Bipin Rawat and others crashed because of its “entry into clouds due to unexpected change in weather conditions in the valley leading to spatial disorientation of the pilot”, the Indian Air Force reported on Friday, releasing a brief summary of the Court of Inquiry report.
Such an entry into the cloud led to “spatial disorientation of the pilot resulting in Controlled Flight into Terrain (CFIT)”, said the IAF.
In aviation terms, CFIT means an unintentional collision of an aircraft with the ground while still in active control.
A CFIT scenario does not generally give the pilot and the co-pilot an opportunity to send out a distress call to the Air Traffic Controllers, because they remain unaware of the impending disaster till it is too late.
Hence, the ill-fated Mi-17 V5 – one of the most reliable helicopters used by the IAF for VIP flights - did not send any distress signal.
The tri-service inquiry, headed by Air Marshal Manvendra Singh, Air Officer Commanding-in-Chief Training Command, ruled out mechanical failure, sabotage or negligence as a cause of the accident.
In one of India’s most tragic military aviation accidents, the chopper ferrying Gen Rawat, his wife Madhulika and 12 others took off from Sulur Air base in Tamil Nadu on December 8 morning for Defence Services Staff College, Wellington where the CDS was to give a lecture. But the chopper crashed minutes before the touchdown killing all but one.
The lone survivor Group Captain Varun Singh succumbed to his injuries at a hospital in Bengaluru after a few days.
The tri-services inquiry team analysed the Flight Data Recorder and Cockpit Voice Recorder besides questioning all available witnesses to determine the most probable cause of the accident.
“The accident was a result of entry into clouds due to unexpected change in weather conditions in the valley. This led to spatial disorientation of the pilot resulting in Controlled Flight into Terrain,” it had said in an earlier report submitted on January 5.
“Based on its findings, the Court of Inquiry has made certain recommendations which are being reviewed,” the IAF said in a statement.
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