Seconds later, the helicopter fell upside down into the water, sparking a desperate rescue operation by city cops and firefighter that saved four people from the treacherous water - but which came too late to save a British woman who was in the city celebrating her 40th birthday.
Federal investigators are now probing the deadly crash that claimed the life of Sonia Marra Nicholson and left her parents - and partner Helen Tamaki - in critical condition.
Pauld Dudley, a veteran pilot, survived unharmed.
"He's very distraught," a source said. "He says he just lost control and it crashed in the water."
A source close to the investigation gave a harrowing account of what happened moments after the Bell 206 Jet Ranger crashed and the chilly water began pouring inside the cabin.
Nicholson's stepdad, 71-year-old Paul Nicholson, was sitting beside Dudley, the source said. Her mother, Harriet, and Tamaki, were sitting with her in the back.
"When it hit the water he unbuckled and tried to get to his wife in the back," the source said of Paul Nicholson. "He was pulled out of the water as he was trying to grab his wife."
Paul Nicholson was rescued by NYPD anti-terror and Emergency Service Unit cops who had been in the area. They immediately shed their gear and leaped into the water.
ESU Det. Keith Connelly said that when he reached the helicopter, he beheld a surreal sight: two men clinging to the chopper and two unconscious women "just bobbing in the water."
"The pilot was by the helicopter, screaming for help," ESU Connelly said. "He was yelling, 'Someone is in the helicopter!'"
Seconds later, the helicopter went under - taking the birthday girl with it.
In the chaos the followed, Dudley somehow drifted away from the officers and was suddenly caught by a swift current about 30 yards from the pier.
That's when Firefighter Robert Lopez of Ladder Company 7 came to his resue.
"He was in shock," said Lopez, 39. "He was saying there was someone in the helicopter still."
"Go get them!" Dudley screamed, according to Lopez.