HOBOKEN, N.J. — New York police divers and crews from the Army Corps of Engineers worked together Tuesday afternoon on efforts to recover the last two victims of a plane-helicopter collision that killed nine people.

Two members of the NYPD dive team went into the water about 3:20 p.m. The plane that collided with the sightseeing helicopter on Saturday is still in the water with one body inside; seven bodies and most of the helicopter have been recovered.

Divers carried a large flat strap, 6 to 8 inches wide, with a large metal shackle on one end, while a crew aboard a second dive boat fed out two cables. Within a few minutes, an Army Corps boat equipped with a large crane moved into position near the site of the wreckage.

The Piper airplane that collided with the helicopter in the congested airspace between New Jersey and Manhattan is in about 60 feet of water, heavily damaged and waterlogged, making recovery delicate, federal safety officials said.

"We're going to be examining the wreckage, looking at the control surfaces, looking for any missing parts, and we may need to do more searching and recovery for any parts that are missing," said Deborah Hersman, chairwoman of the National Transportation Safety Board.

Investigators will check to see whether all the controls were working and if there was power from the engine when the aircraft collided, Hersman said.

"Obviously it's in very deep water," she said. "It's heavy, it's waterlogged and when they pull it out they want to make sure all the aircraft parts remain attached."

One of the two victims was located in the plane's wreckage Monday but couldn't immediately be removed, police said. Police divers placed chains on the front of the plane — resting on its side at the river bottom — near the engine and near the tail Monday to prepare to lift it.

Also on the scene is the 30-ton Moritz, an Army Corps vessel that has a small crane. The ship, normally used to conduct hydrographic surveys, helped search for a missing engine after U.S. Airways Flight 1549 made an emergency landing in the Hudson River in January.

Investigators also planned to conduct interviews with controllers at Newark Liberty International Airport to try to piece together the flight route of the small plane into the Hudson River corridor, where it smashed into the helicopter at 1,100 feet Saturday.

Air traffic control transcripts described Monday indicate a worry-free exchange between controllers at Teterboro, in New Jersey, and the plane's pilot, Steven Altman, who was told he could pick his flight path toward Ocean City, where he was flying after with his brother Daniel Altman and teenage nephew Douglas Altman.

The air traffic controller at Teterboro gave him two choices: Head down the river, or take a southwest tack.

When a Teterboro controller asked the pilot whether he wanted to go down the river or head southwest, he responded by saying: "Either."

"Let me know," the controller said.

"OK, tell you what," Altman replied, "I'll take down the river."

Hersman said controllers at Teterboro at some point told Altman to switch radio frequencies so Newark controllers could communicate with him, but Newark never made contact, she said.

All seven victims whose bodies were recovered have been positively identified through dental records and fingerprints, the New York medical examiner's office said. Autopsies found they died from blunt-impact injuries.

The helicopter had just taken off from Manhattan's West Side for a 12-minute tour. Witnesses said the small plane approached the helicopter from behind and clipped it with a wing. Hersman said the helicopter was gaining altitude when the two aircraft collided.

Both aircraft split and fell into the river, scattering debris and sending weekenders enjoying the beautiful day on the New Jersey side of the river running for cover.

Hays reported from New York. Associated Press writers Sara Kugler and Maria Sanminiatelli in New York and Samantha Henry in Hoboken, N.J., also contributed to this report.