Engine failure is not to blame for Sunday's helicopter crash in the East River that killed five people.
The National Transportation Safety Board says it found "no abnormalities'' when it took apart the engine.
Investigators also interviewed the chopper's pilot for the first time.
The five passengers drowned when the helicopter crashed and capsized.
The NTSB says it's looking into whether the passengers' safety harnesses hindered their escape from the sinking aircraft.