What happened
On the night of November 4, 2015, a Dauphin AS 365 N3 helicopter, registration VT-PWF, was conducting a night training mission in the Bombay High offshore area. The flight, operated by Pawan Hans Limited, was intended to provide night offshore training for a crew member. The flight originated from the WIS platform, having previously arrived from Juhu.
During the approach to the Ron Tappmeyer Rig, the helicopter was flying under Visual Flight Rules (VFR) in a tailwind. As the aircraft approached the helideck, the pilot flying realized the helicopter was too high on the approach and initiated a go-around maneuver. During this transition, the aircraft banked to the left and simultaneously began a descent. Within seconds, the helicopter struck the sea with high velocity, resulting in the total destruction of the aircraft and two fatal injuries to the flight crew.
The investigation
AAIB India investigators examined the wreckage, which was recovered from the deep sea on November 9, 2015. The investigation included a detailed analysis of the flight recorders, wreckage patterns, and engine parameters. Experts from BEA France assisted in analyzing the structural breakage and the condition of the main rotor drive system.
The inquiry scrutinized the operational environment, including the lack of landing aids on the offshore platforms and the absence of formal Standard Operating Procedures (Sought) for night offshore operations. The investigation also reviewed the training records of the crew and the organizational safety management systems of both the operator and the client, ONGC.
Findings
- The pilot flying was experiencing a significant break in night offshore flying experience.
- The approach was conducted at high speed with a tailwind, and the lack of ambient lighting from nearby rigs created a black hole phenomenon.
- This lack of visual horizon led to severe spatial disorientation, causing the pilot to lose awareness of the aircraft's actual flight path.
- The pilot continued to rely on visual references instead of transitioning to instrument flight during the critical phase of the go-around.
- The instructor pilot provided warnings, but these were delayed and ultimately ineffective as the trainee was unable to react.
- The Pilot in Command (PIC) failed to take control of the aircraft when the descent reached a critical height.