The helicopter reportedly crashed near 89th Street in Manhattan around 7 p.m. It is unclear where the helicopter was coming from or if there were any distress calls.
Police say there were six people on board the helicopter, including the pilot at the time of the crash. The pilot was able to free himself, but the passengers were not able to get out - he was taken to the hospital, and is expected to be OK.
It took FDNY and NYPD divers a while to free the passengers from the helicopter, which was upside-down. The passengers were tightly harnessed, so responders had to get them freed.
The aircraft was operated by Liberty Helicopters for a private charter photoshoot.
"We were having dinner and we noticed a red helicopter going full speed towards the water. It almost looked very surreal and next thing we know it's approaching the water slowly and then it just completely crashed and then sunk. Immediate reaction was to call 911," said eyewitness Arineh Nazarian.
The helicopter is now in police possession.
The NTSB says it will be investigating.