Accident Overview
On June 27, 2008, at approximately 1233 Pacific daylight time, a Sikorsky S-76A helicopter, registration N343AA, collided with a steel beam on Oil Platform Irene, located off the coast of Santa Maria, California. Arctic Air Service, Inc. operated the helicopter under 14 Code of Federal Regulations Part 135. The airline transport pilot and eight passengers were not injured; the copilot, also an airline transport pilot, received minor injuries. The helicopter sustained substantial damage.
Flight Details
The flight departed Santa Maria Public Airport at about 1202 with planned stops at Platform Hidalgo, Platform Hermosa, and Platform Irene, before returning to Santa Maria. Visual meteorological conditions prevailed, and no flight plan had been filed. After stops at Platforms Hidalgo and Hermosa, the helicopter departed for Platform Irene with eight passengers on board. The aircraft was to be shut down for a period on the platform.
Landing and Impact
During the approach to Platform Irene, the copilot was at the controls. He reported that about 99 percent of approaches are made to the northeast, but he performed an approach to the southwest due to wind direction. While landing and executing a right pedal turn over the heliport, the tail rotor struck a movable derrick. The copilot lost tail rotor authority and landed immediately. The left main landing gear collapsed, and the helicopter rolled onto its left side. Structural damage occurred to the tail rotor and main rotor assemblies. The operator noted that there were no mechanical malfunctions or failures. Winds were from 220 degrees at 6 knots. The movable derrick on the platform had been positioned as close as possible to the heliport area.
Operator's Observations
The landing deck on Platform Irene measures 50 by 50 feet at an elevation of 110 feet. Other platforms operated by Arctic Air have larger decks, about 70 by 70 feet. According to the operator's written report, the flight deck on Platform Irene had recently been repainted. The "H" symbol was offset from its previous position, and the reference line (used by pilots to determine tail rotor clearance during turns) had not been repainted. The new "H" marking was 23 feet from the southeast edge, while the previous location was about 1 foot farther from that edge. The markings on Platform Irene had differed from other decks before being repainted to match them. The Arctic Air Service Safety Officer reported that the derrick had been moved to its adjacent location 6 days before the accident. Platform Irene is the only platform in the company's operations with a movable derrick that can be positioned within 7 feet of the heliport deck. The deck had been stripped and repainted about 2 months prior.
Recommendations
In the operator's report (NTSB Form 6120.1), under "Recommendation (How could this accident have been prevented)," the operator suggested repositioning the "H" symbol, repainting the reference line, publishing a profile view of the flight deck and surrounding obstacles to aid pilots, and briefing all company pilots on these changes and associated hazards.
An FAA representative stated that there are no FAA regulations defining markings for offshore heliports.