New York, New York - The Spanish family killed when a New York sightseeing helicopter plunged into the Hudson River, leaving no survivors, were celebrating a birthday, a local official said on Friday as divers continued to scour for wreckage.

A senior business executive, his wife, and three children died along with the aircraft's pilot when the helicopter malfunctioned, disintegrating in mid-air before plunging into the cold waterway below on Thursday.

The family was on a pleasure flight over Manhattan, described by the operator as the "ultimate sightseeing tour of New York City."

"They were celebrating the mom's 40th [birthday] with the tourist helicopter flight yesterday. The kids were all 11 [years old] and younger," said Jersey City mayor Steven Fulop.

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A family member was flying in to recover their remains and officials were seeking to expedite the release of the bodies to be repatriated to Spain, he added on X.

National Transportation Safety Board (NTSB) chairwoman Jennifer Homendy declined to comment on the cause of the crash, telling a briefing that "this is the first full day of our investigation... We have a lot of information, but we do not speculate."

"[Investigators] will focus on the helicopter operator. They'll look at the owner of the helicopter itself, and they will look at pilot qualifications and other information. We have experts on helicopter air-worthiness, on structures and on systems. We also have our evidence management team here," she said.

Police divers were continuing to scour the riverbed for components of the helicopter that had yet to be recovered including the main rotor, she added.

The pilot was certified for helicopters and had accumulated about 788 hours of total flight time.

The crash has once again shone a light on US aviation safety in the wake of a string of deadly incidents including the collision between a military helicopter and a passenger jet in Washington in January that claimed 67 lives.

A light aircraft crashed after departing Boca Raton airport in Florida on Friday, the Federal Aviation Administration said, with local media reporting three people had been killed after the plane developed a mechanical issue.

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There have been around 30 helicopter crashes in New York since 1980, Brooklyn Borough President Mark Levine told reporters, calling for tighter restrictions on helicopter traffic.

Images showed the cockpit of the passenger helicopter being lifted from the river by a barge crane overnight, and stored at a nearby Army Corps of Engineers site in Jersey City across the river from Manhattan, Fulop said.

Siemens confirmed that one of the victims was Agustin Escobar, the CEO of a unit under the global technology firm.

The bodies of all six victims, including the three children, were recovered from the water, Mayor Eric Adams told a briefing Thursday. He called it a "heartbreaking and tragic crash."

Video of the incident has emerged showing the cockpit apparently becoming detached from the rotor with the disintegrating aircraft falling into the busy river below.

"It appears that the main rotor struck the body of the helicopter, cutting off the tail of the helicopter, which created an unrecoverable event," said former military aviator and attorney Jim Brauchle of Motley Rice.

"The two main causes of this phenomenon are mechanical failure or excessive maneuvering."

Police and fire service divers raced to pull survivors from the wreckage, rushing two of those rescued to hospital, but doctors were unable to save them.