Incident Overview
A helicopter experienced a main rotor blade strike during takeoff from an offshore platform. The rotor blade contacted the underside of a cable raceway on a drilling rig situated adjacent to the platform helideck. The raceway was located 9 feet laterally and 22 feet above the edge of the helideck.
Sequence of Events
The pilot had landed on the helideck while another aircraft was already parked on the deck. This situation required the pilot to make an approach to a hover, then slide sideways across the pad and set down with the main rotor blades underlapping the bottom of the jack-up drilling platform. After lifting off to a hover, the pilot was attempting to transition to forward flight when the rotor strike occurred. Following the strike, the pilot attempted to inflate.
Operational Procedures
The operator's standard operating procedures (SOP) call for a minimum of one-third rotor disc clearance from all obstacles during takeoff and landing. In this instance, the required clearance could not be maintained because another aircraft was already parked on the helideck.