Five people have died and only one has survived after a helicopter went down in New York's East River on Sunday. According to authorities, the pilot of the helicopter is the sole survivor of the accident.

Three of the passengers were taken to hospital with critical injuries after they initially survived the accident, but the New York City Fire Department confirmed that they had died in hospital. FDNY Commissioner Daniel Nigro said that the sixth person, the pilot, had managed to free himself from the wreck and was rescued. He has now been taken to hospital for observation.

"One of the most difficult parts of the rescue were that five people were tightly harnessed," Nigro said. "People had to be cut out."

Authorities say that the aircraft had been hired from Liberty Helicopters for a private photo shoot. In an audio recording of a mayday call to LaGuardia Airport, the pilot of the helicopter can be heard saying that it was experiencing engine failure.

According to Liberty Helicopters, they are "the largest and most experienced helicopter sightseeing and charter service in New York City".

The company say that they own "a fleet of 10 state-of-the-art Airbus helicopters (formerly American Eurocopter)," according to the website. "We have been in business and flying safely for over 30 years," they say.

According to WABC-TV, this is the company's third crash in 11 years. In August 2009, nine people were killed after a helicopter and a small, private plane crashed into each other over the Hudson River. According to investigators at the time, the helicopter was flying too high.

Two years prior to that, in July 2007, a sightseeing aircraft carrying eight people dropped into the Hudson River. Fortunately, in this case, no one died - as an off-duty paramedic helped everyone escape.

The Federal Aviation Administration confirmed that the helicopter went down at 7 pm in the river near Roosevelt Island. The FAA also identified the chopper as a Eurocopter AS350.

The helicopter was found upside down and submerged by emergency responders. Police then called for a barge with a crane on it in order to pull it out of the water.

The reason behind the crash isn't known, but Gary C. Robb, an aviation attorney based in Kansas City, Missouri, said that the National Transportation Safety Board will be looking at three things: the pilot's training, experience and immediate response during the crash; what on the helicopter may have caused the crash; and what environmental factors may have contributed to the incident.

John J Magers filmed the crash and posted it on Twitter. He said that he thought something odd was going on when he saw to the chopper flying low before the crash.

"I saw it coming down toward the water. Thought it was unusual, but didn't expect it to crash," Magers told CNN over Instagram. "My thoughts are with those killed."

Our thoughts are with all those affected by the crash.

Five people have died and only one has survived after a helicopter went down in New York's East River on Sunday. According to authorities, the pilot of the helicopter is the sole survivor of the accident.

Three of the passengers were taken to hospital with critical injuries after they initially survived the accident, but the New York City Fire Department confirmed that they had died in hospital. FDNY Commissioner Daniel Nigro said that the sixth person, the pilot, had managed to free himself from the wreck and was rescued. He has now been taken to hospital for observation.

"One of the most difficult parts of the rescue were that five people were tightly harnessed," Nigro said. "People had to be cut out."

Authorities say that the aircraft had been hired from Liberty Helicopters for a private photo shoot. In an audio recording of a mayday call to LaGuardia Airport, the pilot of the helicopter can be heard saying that it was experiencing engine failure.

According to Liberty Helicopters, they are "the largest and most experienced helicopter sightseeing and charter service in New York City".

The company say that they own "a fleet of 10 state-of-the-art Airbus helicopters (formerly American Eurocopter)," according to the website. "We have been in business and flying safely for over 30 years," they say.

According to WABC-TV, this is the company's third crash in 11 years. In August 2009, nine people were killed after a helicopter and a small, private plane crashed into each other over the Hudson River. According to investigators at the time, the helicopter was flying too high.

Two years prior to that, in July 2007, a sightseeing aircraft carrying eight people dropped into the Hudson River. Fortunately, in this case, no one died - as an off-duty paramedic helped everyone escape.

The Federal Aviation Administration confirmed that the helicopter went down at 7 pm in the river near Roosevelt Island. The FAA also identified the chopper as a Eurocopter AS350.

The helicopter was found upside down and submerged by emergency responders. Police then called for a barge with a crane on it in order to pull it out of the water.

The reason behind the crash isn't known, but Gary C. Robb, an aviation attorney based in Kansas City, Missouri, said that the National Transportation Safety Board will be looking at three things: the pilot's training, experience and immediate response during the crash; what on the helicopter may have caused the crash; and what environmental factors may have contributed to the incident.

John J Magers filmed the crash and posted it on Twitter. He said that he thought something odd was going on when he saw to the chopper flying low before the crash.

"I saw it coming down toward the water. Thought it was unusual, but didn't expect it to crash," Magers told CNN over Instagram. "My thoughts are with those killed."

Our thoughts are with all those affected by the crash.