US authorities ordered an end on Friday to so-called "doors off" helicopter rides unless passengers are equipped with quick-release restraints, following a crash in New York City last week that killed five people.
The Federal Aviation Administration said operators and pilots must take immediate actions to control or mitigate the risk presented by passengers wearing what it called "supplemental restraints."
"Until then, the FAA will order no more 'doors off' operations that involve restraints that cannot be released quickly in an emergency," the FAA said in a statement.
The agency said it also will conduct a "top to bottom review" of its rules governing such flights to examine any potential misapplication that could create safety gaps for passengers.
The pilot survived but all five passengers were killed on Sunday evening when a Eurocopter AS350 plunged into New York City's East River while on a private "photo shoot" charter.
Two of the five passengers died at the scene and three were taken to local hospitals where they later died, officials said. They had been tightly harnessed and the harnesses had to be cut and removed to free them, officials said.