WEEK 32
H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.
TITLE
Loss of control and ditching during offshore approach.
WHAT?
An S-76 was transporting seven passengers to an offshore installation. During the final approach, the helicopter entered an uncontrolled descent and struck the sea.
WHERE?
Sagar Kiran offshore installation, around 57 nautical miles west of Mumbai, India.
WHEN?
28 June 2022
HOW?
During the final approach, the autopilot was disengaged and the co-pilot assumed manual control. At approximately 700 ft, the commander, acting as pilot monitoring, became occupied with switching the co-pilot’s weather radar to standby.
The co-pilot operated the cyclic trim-release button and progressively increased the helicopter’s nose-up attitude while reducing collective pitch. Pitch reached approximately 23.5° nose up while forward speed decreased towards zero and the helicopter entered a steep descent.
The developing deviation went unchallenged while the commander was head-down. Following ground-proximity warnings, he intervened and applied maximum collective, but rotor RPM decayed and insufficient height remained to recover. The helicopter struck the sea, its emergency flotation system deployed and it overturned.
CONDITIONS?
The accident occurred in daylight during the monsoon season. Weather was unsettled, with drizzle reducing visibility, and cumulonimbus activity. The crew had already diverted around CB clouds during the outbound flight.
The offshore installation reported light drizzle, winds of 3–4 kt. Its weather log recorded a swell of 1.5–2 m, although visibility at the platform was not recorded.
The S-76D was relatively new to the operator’s fleet, and the investigation identified inadequate crew familiarity and proficiency with its automatic flight-control system.
OUTCOME?
All nine occupants survived the impact and escaped the overturned helicopter. Four people, including both pilots, remained near the aircraft and were rescued by an offshore support vessel. Five passengers drifted away in rough seas; one was rescued, but the other four drowned before rescuers reached them.
All nine occupants escaped the helicopter, which overturned but remained afloat on its emergency flotation system. However, five passengers drifted away in the 1.5–2 m swell. One was rescued; the other four drowned.
The investigation found that three of the four deceased passengers had not inflated their lifejackets. Several passengers had mistakenly operated the emergency rebreather activation toggle rather than the inflation toggle. The safety briefing video and passenger briefing cards depicted different lifejackets from those actually supplied, providing incorrect instructions.
Rescue arrangements compounded these difficulties. The platform’s fast rescue craft had been unserviceable for over a year, so a conventional enclosed lifeboat was launched instead. It recovered one passenger but returned to the platform without rescuing the remaining occupants. An offshore support vessel took approximately 45 minutes to reach the ditched helicopter. By then, four passengers had drifted away and drowned.
WHY?
The investigation attributed the accident to an aggressive, pilot-induced nose-up manoeuvre combined with full collective lowering, resulting in an unrecoverable descent. It identified several contributing factors:
- Inappropriate use of cyclic trim release and excessive nose-up control inputs, could have been associated with inadequate type-specific familiarity and proficiency.
- The commander did not prioritise monitoring during a critical phase, and undertook a head-down radar task delaying recognition and intervention of the flight path deviation.
- The crew was not sufficiently familiar with the S-76D’s flight-control system contributed to inappropriate handling during the transition to manual flight.
- Training and operational supervision weaknesses were identified as contributing factors.
- Passenger safety arrangements and the offshore rescue response following the impact were insufficient.
The accident demonstrates that surviving the impact and successfully escaping a ditched helicopter are only the first stages of survival. Correctly operated equipment, effective passenger training and a timely, capable rescue response are equally critical.
REFERENCE?
Aircraft Accident Investigation Bureau. (2023). Final investigation report on accident involving Pawan Hans’ S-76D helicopter VT-PWI at Mumbai offshore on 28 June 2022.
Note:
Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.
