Sikorsky S-76C N552J accident near New York, New York

Probable cause

The failure of the flightcrew to stabilize the helicopter over its confined landing area during a hovering left-pedal turn, resulting in tail rotor blade contact with a perimeter fence component and a subsequent loss of directional control. Contributing to the accident was the inadequate markings of the heliport and heliport spots, and failure of FAA personnel to detect the inadequate heliport markings during inspection of the heliport approximately 1 month prior to the accident.

NTSB analysis

While maneuvering over the heliport, the co-pilot flying the helicopter maneuvered it near the center of spot H2 (designated for the size of the accident make and model helicopter), which did not include a shoulder line in accordance with Advisory Circular 150/5390-2B. While making a left pedal turn, the co-pilot allowed the helicopter to hover rearward east of the center of spot H2 towards a 12 foot tall chain link fence located behind spot H2; no ground personnel were assisting. While moving forward towards the center of spot H2, the tail rotor blades contacted a portion of the fence resulting in separation of 4 to 6 inches from each tail rotor blade, and subsequent loss of directional control. The flightcrew lowered collective and the helicopter impacted hard causing collapse of the left main landing gear. No preimpact failure or malfunction was noted to any systems of the helicopter. While heliport personnel reported the yellow line is to be used for ground taxiing only, review of an advisory circular related to heliport design revealed that with respect to taxi lines, they need to be marked as such to provide minimum clearance for the largest operating helicopter the heliport is expected to receive. Inspection of the heliport by FAA personnel 1 month prior to the accident failed to detect inadequate heliport markings.

Text from the NTSB. Open the NTSB docket for ERA09LA020 for the full record.