The parents of one of the five people killed Sunday when a helicopter crashed into the East River during a private photo tour of New York City have filed suit against the helicopter’s pilot, the company that ran the tour and others, claiming negligence.

>> Read more trending news

Jerry and Nancy Cadigan, the parents of 26-year-old recent New York transplant Trevor Cadigan, filed suit Tuesday in New York State Supreme Court, according to The Wall Street Journal. The family claims that the helicopter Cadigan rode in was a "death trap" because its passengers were required to strap themselves into complicated harnesses to allow the helicopter to fly with its doors open.

"There was no prospect of his safely evacuating this helicopter in that crash scenario," attorney Gary C. Robb, who is representing the Cadigans, told the Journal.

Among those named in the suit were Richard Vance, the 33-year-old pilot and only survivor of Sunday’s crash, and Liberty Helicopters, the company that ran the tour.

Five people were killed in the accident, which happened around 7 p.m. Sunday. They were identified by police as New York residents Daniel Thompson, 34, and Tristan Hill, 29; Argentinian tourist Carla Vallejos-Blanco, 29; Dallas firefighter Brian McDaniel, 26; and Cadigan, who had recently moved from Dallas.

In this image made from an undated video released by WFAA in Dallas, Trevor Cadigan, a former WFAA intern and son of WFAA production manager Jerry Cadigan, is seen. Cadigan was among five passengers killed Sunday when a helicopter plunged into New York City's East River, with the pilot reporting the engine had failed. (Courtesy of WFAA via AP)
icon to expand image

Vance was able to immediately free himself from his harness, according to ABC News, but the passengers were not able to follow suit. The Dallas Morning News reported the passengers wore harnesses that released from the back.

Officials said the helicopter quickly filled with water after the accident and began to sink because it fell into the East River with its doors open.

In the Cadigans lawsuit, a copy of which was obtained by ABC News, the family accused Vance of being "careless in failing to take reasonable steps to extricate the passengers" after he freed himself from his harness.

"Hanging upside-down in frigid water — stunned by the helicopter crash, tightly harnessed, release inaccessible, with no advanced training — is a death trap," Robb told the Morning News.

Also named in the lawsuit were helicopter charter FlyNYON and aviation services company NYONAir, ABC News reported. The Cadigans said the companies "implemented a policy to cinch passengers into heavy duty harnesses which are tied to the helicopter floor with only a knife for passengers to free themselves from (frigid) waters."

They said that the companies were negligent for allowing their tours to fly with helicopter doors open.

“(It) is inordinately dangerous and risky and should only be permitted for professional photographers in special situations and not for amateur tourist photographers,” the lawsuit said.

Vance told investigators that he believed one of the passenger's bags might have accidentally hit the helicopter's emergency fuel shutoff button, causing the crash, CNN reported. In an emergency radio transmission obtained by The Associated Press, Vance could be heard saying that his helicopter had an engine failure.

The National Transportation Safety Board is investigating the crash.