Incident Overview
Two Sikorsky S-76A helicopters, registered as N586C and N760P, experienced a rotor blade intermesh at the Wall Street Heliport/Parking Barge. N586C had landed seven minutes earlier and was parked in spot 11 with its rotors still turning, awaiting passengers. N760P was arriving and landed in spot 12.
Communication and Parking Layout
The UNICOM operator informed the pilots of N760P that another helicopter was "turning on spot 11" and instructed them to park alongside at their discretion. The barge contained 12 parking spots. Spots 4, 5, and 6 were designated for Sikorsky S-76 helicopters and measured 57 feet between pad centers. The remaining spots were intended for Bell 222 helicopters, with 45 feet between pad centers. The main rotor span of an S-76 is 44 feet.
Positioning and Contact
N586C was parked approximately four feet left of spot 11's centerline. N760P landed in the center of spot 12, which was located to the left of spot 11. As N760P settled, the main rotor blades of both helicopters intermeshed.
Lack of Advisory Information
Neither crew had been advised that spots 4, 5, and 6 were designated for larger aircraft like the S-76. Existing FAA advisories for heliports did not provide markings indicating the maximum acceptable rotor diameter for designated parking areas.