The helicopter took off from the southern edge of Manhattan, before circling up the west side of the island down the Hudson River, Flight Radar tracking shows.

It U-turned close to the northern edge of Manhattan, and almost made it back down the Hudson until it crashed close to Hoboken in New Jersey.

One witness said he saw the plane ‘falling apart’ as it tumbled down towards the water in several pieces, around 500 meters from the nearest pier.

‘The propeller was still in the sky, and (the helicopter) just slammed into the water,’ he told NBC New York.

‘The plane was turned around, sitting there in the water, almost like it was floating,’ he added.

Brian Marks was at Penny Park in Manhattan with his children when the helicopter went down. He described hearing a ‘loud thump’ when it hit the water.

‘One of my children said, “what’s that sound?” I told him I didn’t know,’ Marks told DailyMail.com.

Marks said he often kayaks in the river and has had Red Cross water safety training.

‘In this river, at this time of day and with this temperature hypothermia will kill you quickly,’ he said.

Lesly Camacho, a hostess at a restaurant along the river in Hoboken, New Jersey, said she saw the helicopter spinning uncontrollably before it slammed into the water.

‘There was a bunch of smoke coming out. It was spinning pretty fast, and it landed in the water really hard,’ she said in a phone interview.

Witness Bruce Wall said he saw the helicopter ‘falling apart’ in midair, with the tail and propeller coming off.

The propeller was still spinning without the aircraft as it fell, he said.

A harrowing video transcript from inside a doors-off sightseeing helicopter which crashed in New York City’s East River in March 2018 has re-emerged in the wake of Thursday’s deadly crash.

The old clip showed doomed passengers struggling to free themselves from harnesses as the aircraft filled with water, officials said.

‘How do I cut this?’ one passenger can be heard asking, just 13 seconds before the helicopter became completely submerged in the river between Manhattan and Brooklyn.

The National Transportation Safety Board made a transcript of the video public in September 2019, but the footage itself was not provided.

It was taken from a GoPro camera mounted on the cabin ceiling. Investigators had been looking at whether the harnesses hindered passengers’ escape from the helicopter, which flipped over and quickly sank.

The transcript painted a picture of tragedy that unfolded in mere seconds, with one passenger reaching for a spot on his chest where a hook knife had been seen earlier, another pulling in vain at the shoulder straps of his harness and a third heard panting.

The rescue craft were near the end of a long maintenance pier for a ventilation tower serving the Holland Tunnel on the New Jersey side of the river.

Rescue crews had to deal with 45-degree water temperatures.

Fire trucks and other emergency vehicles were on nearby streets with their lights flashing.

The Federal Aviation Administration identified the helicopter as a Bell 206. The FAA and the National Transportation Safety Board are planning to investigate.

‘It sounded like a sonic boom on my right,’ a witness told ABC affiliate WABC.

‘I looked up and literally just see a helicopter splitting in two with the rotor flying off into the sky.

‘It was going so fast and it just went straight into the water. I’ve never seen anything like that in my life.’

The tragedy marks the latest in a series of aircraft disasters in the area in recent years, including a 2018 crash of a charter helicopter offering ‘open door’ flights that went down into the East River between Manhattan and Brooklyn, killing five people.

In 2009, another tourist helicopter also collided with a plane over the Hudson River, killing nine people.

Six people have been confirmed dead in the crash, including three children, according to the Associated Press.

At least three people have died after a helicopter carrying two adults and three children plunged into the Hudson River between New York City and New Jersey.

The horrific incident unfolded just before 3.30pm on Thursday, closer to the Garden State side of the river, according to police.