A helicopter is hoisted by crane from the East River onto a barge, Monday in New York. The pilot was able to escape the Sunday night crash after the aircraft flipped upside down in the water killing several passengers, officials said. Credit: Mark Lennihan | AP

NEW YORK, New York — A Texas firefighter, an Argentine woman and a video journalist were among five passengers killed when a helicopter plunged into New York City’s East River, with the pilot reporting the engine had failed.

Investigators began working Monday to determine what caused Sunday night’s crash. It killed everyone aboard except the pilot, who managed to free himself as the helicopter flipped over and rapidly sank into the water.

As the aircraft foundered, he made a mayday call and added: “East River — engine failure.”

The slain passengers included Fire-Rescue Officer Brian McDaniel; Trevor Cadigan, a video journalist who hailed from Dallas but had recently worked at a business news site in New York; and Carla Vallejos Blanco, who was from Argentina, according to its consulate.

McDaniel, 26, had been with the Dallas Fire-Rescue Department since May 2016.

“Despite his short tenure, hearts are heavy with grief,” the department said in a statement.

Cadigan, also 26, had most recently been an intern at Business Insider until a few weeks ago.

“He was a smart, talented, and ambitious young journalist and producer who was well-liked and made a big contribution,” the news site said in a statement

A 2016 graduate of Southern Methodist University, he had previously freelanced with an entertainment and culture site managed by the Dallas Morning News, writing and producing videos on such topics as craft beer, and interned with his hometown’s WFAA-TV. His father, Jerry, is the station’s production manager.

The Eurocopter AS350 helicopter had been chartered for a photo shoot. It went down about 7 p.m. in the water near New York’s mayoral residence.

As the aircraft foundered, the pilot was heard on an emergency radio transmission calling: “Mayday, mayday, mayday.”

“East River — engine failure,” he added.

The pilot was rescued by a tugboat, but emergency divers had to remove the passengers from tight safety harnesses while they were upside down, Fire Commissioner Daniel Nigro said.

“It took a while for the divers to get these people out. They worked very quickly, as fast as they could,” Nigro said. “It was a great tragedy that we had here.”

The National Transportation Safety Board dispatched investigators on Monday. Several officials in NTSB jackets looked on from a dock as police divers went into the water around the submerged chopper, apparently to hook it to a crane that would lift it from the water.

The cause of the crash has not been determined.

Video taken by a bystander and posted on Twitter shows the red helicopter land hard and then capsize, its rotors slapping at the water.

Witnesses on a nearby waterfront esplanade said the helicopter was flying noisily, then suddenly dropped and quickly submerged. But the pilot appeared on the surface, holding onto a flotation device as the tugboat and then police boats approached.

“It was sinking really fast,” witness Mary Lee, 66, told the New York Post.

The aircraft was owned by Liberty Helicopters, a company that offers both private charters and sightseeing tours popular with tourists.

The company referred inquiries to authorities, saying it was focused on the victims’ families and the investigation.

The skies over New York constantly buzz with helicopters carrying tourists, businesspeople, traffic reporters, medical teams and others.

In 2009, a Liberty Helicopters sightseeing craft of the same model as the one in Sunday’s wreck collided with a small, private plane over the Hudson River, killing nine people, including a group of Italian tourists.

A helicopter crash in October 2011 in the East River killed a British woman visiting the city for her 40th birthday. Two other passengers died weeks later as a result of their injuries.

A helicopter on a sightseeing tour of Manhattan crashed into the Hudson River in July 2007, shaking up the eight people aboard but injuring no one. In June 2005, two helicopters crashed into the East River in the same week, injuring a total of 15 people.

Nigro and Police Commissioner James O’Neill said the rescue operation Sunday took place in a 4 mph current in water about 50 feet (15 meters) deep, under challenging conditions.

Associated Press writers Claudia Lauer in Dallas and Claudia Torrens in New York contributed to this report.

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