What happened
On December 11, 2016, a Robinson R-44 helicopter, registration VT-PHB, was conducting a scheduled joy ride over Mumbai. After successfully completing its first sortie, the aircraft departed Juhu Aerodrome for a second sightseeing flight carrying a pilot, a technician, and two passengers. The flight path was intended to traverse Powai and Vihar lakes before returning to Juhu.
While cruising at approximately 500 feet, the pilot experienced a sudden reduction in engine RPM and notified Air Traffic Control of a clutch failure, declaring an emergency forced landing in the Powai area. During the descent, the pilot attempted to maneuver the aircraft away from a group of children playing in the intended landing zone. In an effort to avoid workers in a nearby field, the pilot executed a right yaw, which caused the helicopter to sideslip and roll into a grove of trees and bushes. The aircraft struck the ground and immediately caught fire.
The investigation
The AAIB India investigation focused on the mechanical failure of the clutch and the pilot's emergency procedures. Investigators examined the wreckage, which showed the cockpit was destroyed by post-impact fire and the rotor blades lacked frontal impact marks, suggesting the pilot had utilized all available kinetic energy to flare the aircraft. The investigation also reviewed the cockpit configuration, noting that the clutch circuit breaker was located under the co-pilot's seat and lacked the red collar intended to make it easily identifiable by touch during high-stress situations.
Findings
- The pilot successfully entered autorotation following the clutch failure.
- The pilot's decision to deviate from the initial landing site to avoid children and workers led to a loss of rotor RPM and a subsequent roll during the final impact.
- The clutch failure was the primary mechanical trigger, though the exact cause of the component failure could not be determined.
- The clutch circuit breaker was difficult to access quickly due to its location and lack of a high-visibility red collar.
- The aircraft's engine remained running after the impact, contributing to the post-crash fire.
Safety action
- The investigation noted that the DGCA may review the operator's revised Standard Operating Procedures (SOP) to enhance safety following the accident.