Flight Crew Rotorcraft; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 30; Flight Crew Total 6000; Flight Crew Type 4000
Other / Unknown; Communication Breakdown
Conflict NMAC
Flight Crew Took Evasive Action
Human Factors; Procedure
While holding in the prescribed pattern over the East River exclusion in NYC; we joined two other helicopters who were also in the hold. The pattern is 1;000 feet AGL left hand turns from the 59th St Bridge to the Williamsburg Bridge along the banks of Manhattan; Brooklyn and Queens. A seaplane was departing the river to the north; and another seaplane was in a downwind on the Brooklyn side; southbound; opposite the helicopter holding pattern. On our second circuit; turning south from the 59th St Bridge a seaplane reported north of the bridge. We had visual contact before completing our turn; and then we lost visual contact. About midway on the south leg of our hold we were cleared to land. As I started my left descending turn the seaplane that was behind and above me was now fully in the left cockpit window and slightly lower. I jerked up on the collective to stop our descent because I thought we would collide. We had no TCAD warnings; and heard no reports from the seaplane of their intentions other than the initial report. We have made inquiries with the heliport manager; LGA Tower; and the Eastern Region Helicopter Council (ERHC) as to the procedures that the seaplanes use. Why the seaplane chose to fly below holding traffic and attempt to pass us from a blind spot without any communication is an unknown.
Helicopter pilot experiences a NMAC with a seaplane over the East River exclusion in NYC while turning to land at the East 34th Street Heliport.