What happened
The pilot had successfully landed the helicopter on an offshore platform. While in the process of repositioning the aircraft to one side of the landing pad to provide additional space for another incoming aircraft, the main rotor blades struck a three-foot steel sign post.
The impact caused the blade to separate into three distinct pieces. This event created a severe out-of-balance condition within the main rotor system. The resulting forces pulled the transmission out of the airframe and caused the upper portion of the cabin and the tail boom to separate from the aircraft.
The investigation
Examination of the wreckage revealed that the main rotor blade had separated into three pieces following contact with a fixed object on the landing pad. The separation led to a severe imbalance in the main rotor system, which subsequently pulled the transmission out of the airframe and caused structural failure of the upper cabin and tail boom.
Findings
- The main rotor blades struck a three-foot steel sign post during repositioning maneuvers.
- The blade separated into three pieces, causing a severe out-of-balance condition in the main rotor system.
- The transmission was pulled out of the airframe due to the imbalance.
- The upper portion of the cabin and the tail boom separated from the aircraft.
Safety message
Operators should ensure adequate clearance around landing pads to prevent rotor blade strikes with fixed objects during repositioning or parking maneuvers.