Lawmakers Sunday called for tighter regulation of air operations over New York City, a day after a midair collision between a sightseeing helicopter and a small private plane killed as many as nine people.

A Piper Lance prop plane carrying two brothers and a teenage boy crashed shortly before noon into the rear of a Eurocopter AS-350 that had set off on a 12-minute jaunt over Manhattan with five Italian tourists and Jeremy Clarke, a 32-year-old pilot.

The impact ripped off one of the Piper's wings and sent both aircraft plunging into the Hudson River, not far from the spot where US Airways pilot Chesley Sullenberger executed his successful water landing of Flight 1549 in January.

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Emergency crews Sunday recovered the bodies of seven of the nine victims from the river between New York and New Jersey. The wreckage of the aircraft was also being retrieved, with the hope of recovering clues to aid the National Transportation Safety Board's investigation.

Neither craft was equipped with the data recorders installed on commercial planes. So investigators will closely examine eyewitness accounts and photographs of the crash to determine how it happened.

PHOTOS: Grim Recovery Effort (Warning: Graphic)

Debbie Hersman, chairwoman of the NTSB, said Sunday that evidence suggested that the helicopter, operated by New Jersey-based Liberty Helicopters, was gaining altitude when the collision occurred. That suggests the helicopter may have been flying in a blind spot for Steven Altman, the pilot of the Piper Lance and one of the brothers aboard.

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