What happened
On September 23, 2019, an AS350 B3e helicopter, registration VT-UTC, was conducting passenger shuttle services between Phata and the Shri Kedarnath Ji helipad. After completing several successful sorties, the aircraft was preparing for a departure from the Kedarnath helipad with six passengers on board.
During the takeoff phase, the pilot initiated a sharp left turn to quickly vacate the helipad for following traffic. This maneuver, combined with high density altitude and a heavy load, triggered an unanticipated leftward yaw. The pilot attempted to correct the rotation using the right rudder, but the aircraft entered a worsening spin. To prevent a more serious accident, the pilot performed an immediate descent, resulting in a hard landing on the right skid. While there were no injuries to the pilot or the six passengers, the aircraft suffered significant structural damage, including a deformed skid and a separated tail rotor assembly.
The investigation
AAIB India investigators examined the aircraft's maintenance history and the operational environment at the high-altitude helipad. The investigation revealed that earlier that morning, the pilot had verbally reported sluggish rudder pedals to an engineer, though this issue was not formally documented in the aircraft logs. Maintenance records showed that the tail rotor blade assembly had been replaced recently, and a recent engine change had been completed.
Investigators also analyzed the flight dynamics at the time of the accident. They noted that the helicopter was operating near its maximum takeoff weight at an elevation of approximately 11,300 feet. The investigation focused on the interaction between the pilot's rapid turning maneuver, the prevailing wind conditions, and the aerodynamic limitations of the aircraft during high-altitude, power-limited operations.