The MI-172 Mesco helicopter that crashed on August 11 last year killing 23 ONGC personnel and four crew on board had been grounded just four days earlier to replace key components, including the tail rotor shaft and the gear box. In fact, maintenance work continued right until the morning of the crash. And there is no evidence to show that requisite tests were done before allowing the chopper to take off with passengers.
This is the startling revelation in the confidential inquiry report submitted to the Directorate General of Civil Aviation (DGCA) this week. The 51-page report, obtained by The Indian Express, has a wealth of detail: on how poor maintenance compounded by pilot error caused one of the worst crashes in India’s chartered flight sector. And snatches of personal and poignant details from on board the flight minutes before it crashed into the Arabian Sea after take-off from the ONGC helideck.
Like crew members discussing the fall in share prices and the quality of coffee served before take-off. ‘‘Is this cold water or bloody hot coffee?’’ a crew member had asked.
For Mesco, the Mumbai-based company which operated the helicopter and employed the crew, the report is bad news although the helicopter had a vaild certificate of registration and airworthiness. The inquiry’s findings expose glaring loopholes in its maintenance set-up and suggests that the ‘‘extreme haste with which the operators were handling sensitive flying operations’’ could have been one factor behind the crash.
The salient findings in the report:
• On August 8 (four days prior to the crash) the helicopter was grounded to replace the tail rotor drive shaft, intermediate gear box and tail gear box because these units were reaching their ‘‘life limitation.’’
Work continued until the morning of August 11—the day of the crash. No checks were done before take-off.
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What needs to be
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The crash probe report recommends:
• Russian helicopter systems should be closely monitored
• Detailed maintenance procedure sheets should be prepared for MI-172 choppers
• Small operators should be made to give names of engineers who carry out inspections, even if they are not on the rolls
• Safety audit of all helidecks
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• As the chopper’s rudder controls are disturbed while changing these units, the control adjustment has to be done. No records available to show that this was indeed done.
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• From August 7 to 11, the ‘‘travelling control transmission’’ was also replaced. There are no documents confirming the reliability of the new adjustment. After replacement, the crew switched on the engines and hovered for (only) three minutes to test the systems.
• Cockpit conversations show that the pilots had detected ‘‘abnormalities’’ in the right pedal. Pedal’s records show that the new control system wasn’t regulated.
• The Digital Flight Data Recorder (DFDR) data show that the sensor was not properly installed during maintenance work and so the tail rotor’s pitch values were not recorded.
• Evidently, the pilot was in haste, the liftoff was ‘‘unusually quick.’’
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• The emergency flotation system was not switched on during the fall of the helicopter and its activation button remained closed.
