The call came in at approximately 3:30 p.m. and crews from Ladder 7, Engine 21 and Engine 7 were the first on the scene, according to a department news release.
The firefighters had to scale a 15-foot barbed-wire fence to gain access to the river.
At that point, the helicopter was upside down in the river and three victims were standing on its struts while another victim was swimming about 20 feet away.
Capt. Chris Richie from Engine 21 directed members from Ladder 7 to the victims.
Firefighter Robert Lopez donned his water rescue gear with the assistance of his colleagues and jumped 10 feet into the water and swam toward the victim as Firefighter Alan Squire served as his backup.
"You want to help," he said. "I was just focused on getting to him."
Once he reached the victim, Lopez handed him a life ring and they were both pulled to safety by the other firefighters.
He said the man was stressed and in shock and kept shouting: 'There is one more person in the helicopter!'"
Arriving NYPD officers rescued the victims standing on the struts shortly before the helicopter sank into the river.
The pilot of the helicopter carrying tourists refused medical attention while two women were transported to Bellevue Hospital and a man was transported to NYU Medical Center.
One woman was killed in the crash and her body was recovered from the river.
