NEW YORK (CBSNewYork/AP) — An attorney for the family of one of the five people who were killed when a helicopter crashed into the East River says they plan to sue chopper owner Liberty Helicopters and others.

The lawsuit spotlights the harnesses used in the open-door flight and notes the aircraft’s inflatable floats didn’t keep it from flipping over and sinking.

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The way passengers were harnessed, with a release mechanism in the back, there “was just no prospect of safely escaping,” said Gary C. Robb, a lawyer for the parents of 26-year-old Trevor Cadigan.

“Hanging upside-down in frigid water — stunned by the helicopter crash, tightly harnessed, release inaccessible, with no advanced training — is a death trap,” said Robb, based in Kansas City, Missouri.

The lawsuit seeks unspecified damages, but Robb said Cadigan’s parents mainly want to end open-door flights for taking aerial photos.

“We want to hold the helicopter company fully accountable for the death of Trevor and we would like the company to cease and desist this reckless and unsafe helicopter operation,” Robb told CBS2.

Liberty Helicopters hasn’t responded to requests for comment and referred all inquiries to federal authorities.

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The NTSB said the aircraft had been flying about 2,000 feet over New York on a scheduled 30-minute flight when the pilot sent out a mayday call saying his engine had failed.

After the helicopter made a hard landing in the water, it tipped over and was carried upside-down in the fast river current while police and fire department divers tried to free the passengers from their safety harnesses.

Sources tell CBS2 the pilot first considered landing in Central Park, but that it was too dark at the time.

Two victims died in the water. Three more were pronounced dead after several hours of treatment at a hospital.

NTSB investigators said electronic devices recovered from the helicopter or from the victims, including the GoPro camera and data recorder, were being sent to laboratories in Washington. Officials also were examining the restraint systems.

(credit: CBS2)

Besides Cadigan, the others who died in Sunday’s crash include a Texas firefighter, an Argentine tourist, a former basketball team assistant and a 34-year-old man.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)