Federal regulators, spurred by a deadly helicopter crash into a river, ordered a temporary nationwide ban on open-door flights that have tight seat restraints that could trap people during emergencies.

The Federal Aviation Administration on Friday grounded the flights amid concerns that harnesses meant to kept passengers from tumbling out of their seats wound up preventing them from escaping when a helicopter plunged into the chilly East River on Sunday.

The pilot got out, but all five passengers died.

The parents of a man killed in the crash, 26-year-old Trevor Cadigan, called the helicopter’s harnesses a “death trap” in a lawsuit. Their lawyer, Gary C. Robb, said the restraints fasten in the back and are difficult to unlatch, especially when a helicopter is tossed upside down.

Passengers often get knives to cut themselves free, Robb said, but doing so isn’t easy for a novice in dark, cold water.

Helicopters affected by the ban can’t conduct open-door flights until they’re equipped with restraint systems that open with one action, the FAA said. The FAA said it would also conduct a “top to bottom review” of its rules covering open-door flights.

Open-door flights, sometimes called doors-off flights, offer sweeping, unobstructed views of landmarks and skylines, making them popular with tourists and photographers who often dangle their feet outside. FlyNYON, the company that organized Sunday’s photo flight, advertises its trips as a chance to take a “shoe selfie.”

FlyNYON and helicopter owner Liberty Helicopters did not immediately respond to messages on Friday. Liberty has been referring questions to federal authorities.

The cause of Sunday’s crash hasn’t been determined.

A federal official told The Associated Press that pilot Richard Vance told authorities he believed a passenger’s bag might have hit an emergency fuel shutoff switch just before the chopper went down. The official was briefed on the investigation but was not authorized to speak publicly about it and spoke on the condition of anonymity.

Fire department commissioner Daniel Nigro said divers had to cut passengers out because the harnesses had kept them strapped to their seats as the helicopter sank in the river. The passengers, four men and one woman, drowned, the medical examiner said.

Cadigan’s parents sued Liberty Helicopters this week, seeking unspecified damages and an end to open-door flights for aerial photography.

Robb said they were “extremely gratified and appreciative” that the FAA took action to ban difficult-to-open harnesses. He called it “long overdue and too little, too late” for the victims of Sunday’s crash.

“Their goal with this legal action has always been primarily to see that no one else dies because of this practice,” Robb said.

(AP)