The accident, which Mayor Michael Bloomberg called "not survivable," happened just after noon and was seen by hundreds and maybe even thousands of people out enjoying a crystal clear summer day.
The two aircraft went down just south of the stretch of river where a US Airways jet landed safely seven months ago. But this time, there was no miracle.
"This is not going to have a happy ending," Bloomberg said. He said, hours after the accident, that he thought it fair to say "this has changed from a rescue to a recovery mission."
Two bodies were recovered in the water, one floating free and one in the wreckage, and other bodies were spotted in the debris, the mayor said. The crash victims included five Italian tourists and a pilot on the helicopter and the three people on the plane, including a child, Bloomberg said.
Witnesses described the same scene: a low-flying plane smashing into the helicopter, and then wreckage scattering. The plane's wing was severed by the impact.
The plane, a Piper PA-32, had just taken off from Teterboro Airport in New Jersey and was headed to Ocean City, N.J., authorities said. The helicopter was a Eurocopter AS 350 owned by Liberty Tours, a sightseeing and charter company. It was struck by the plane shortly after lifting off from a heliport on Manhattan's West side.
At least some people saw the crash developing. Another Liberty Tours helicopter pilot on the ground at the heliport saw the plane approaching the helicopter and tried to radio an alert to the pilots, New York Police Commissioner Raymond Kelly said. The warning either wasn't heard, or didn't happen in time.
Kelly Owen, who was visiting from Florida, saw the crash from a Manhattan park built upon an abandoned elevated rail line.
"First I saw a piece of something flying through the air. Then I saw the helicopter going down into the water," she said, adding that the crowd in the park seemed too stunned to react. "I thought it was my imagination."
On the Hoboken waterfront, people scattered as pieces of debris fell from the sky. A wheel from one of the aircraft lay on Hoboken's Sinatra Drive.
"We saw the helicopter propellers fly all over," said Katie Tanski, of Hoboken.
Afterward, much of the wreckage sank quickly into the river.
The cause of the crash wasn't immediately clear, but the National Transportation Safety Board was investigating, Bloomberg said.
The accident happened in a busy general aviation corridor over the river that is often filled with sightseeing craft on nice days.
Pilots have some freedom to pick their own route, as long as they stay under 1,000 feet and don't stray too close to Manhattan's skyscrapers. The skies over the river are often filled with pleasure craft, buzzing by for a view of the Statue of Liberty.
Accidents aren't frequent, but happen every few years. New York Yankees pitcher Cory Lidle and his flight instructor died when their plane hit a skyscraper while flying a popular sightseeing route in 2006.
In January, the river was the scene of a spectacular aircraft landing that resulted in no loss of life after a US Airways flight taking off from LaGuardia Airport slammed into a flock of birds and lost power in both engines. The plane crash-landed in the river, and all 155 people on board were pulled to safety.
The identities of the victims of Saturday's crash were not immediately released. Italian Foreign Ministry spokesman Maurizio Massari confirmed there were Italians aboard the helicopter and said the ministry was working to find out further details through diplomats and authorities in New York.
A person who answered the phone at a Liberty Tours office declined to comment on the accident, but said the company would be releasing a statement. The company runs sightseeing excursions around the Statue of Liberty, Ellis Island and Manhattan at costs ranging from $130 to about $1,000.
Two years ago, a Liberty helicopter fell 500 feet from the sky during a sightseeing trip. The pilot was credited with safely landing the chopper in the Hudson and helping evacuate her seven passengers.
In 1997, a rotor on one of its sightseeing helicopters clipped a Manhattan building, forcing an emergency landing. No one was hurt.
