Searchers pulled more bodies and helicopter wreckage from the Hudson River's murky waters today as investigators sought the cause of the fatal midair collision Saturday between a tour helicopter and a small plane in the waters off New York City.
Divers recovered seven bodies from the river after the accident that killed nine, National Transportation Safety Board chairwoman Deborah Hersman told reporters late this afternoon.
Hersman added that searchers retrieved the twisted remains of the helicopter from 30 feet of water near Hoboken, N.J., and moved it to a pier for further examination.
Crews also believe they had located the Piper plane on the river bottom via sonar -- or, at least, "a number of promising targets," Hersman said -- though that wreckage had yet to be retrieved.
"The river bottom is very murky, and it is hard for divers to see in front of them," Hoboken Police Chief Anthony Romano said of the complexity of the search. "They are almost operating in the dark."
Federal safety investigators said the collision happened shortly after the Piper Lance airplane took off from Teterboro, N.J.
Pilot Steve Altman, 60, of Amber, Pa., his brother Daniel Altman, 49, of Dresher, Pa., and Daniel's son Douglas Altman, 15, were headed to Ocean City, N.J., for a day at the beach.
The tour helicopter, operated by Liberty Helicopters, had just taken off from New York's 30th Street Heliport for a 12-minute tour, officials said.
On board were a 32-year-old pilot -- Jeremy Clark of Lanoka Harbor, N.J., Liberty told the AP -- and five Italian tourists, including a family celebrating a 25th wedding anniversary in New York.
The passengers -- Fabio Gallazzi, 49, his wife Tiziana Pedrone, 45, and their son Giacomo, 16, as well as father and son Michele Norelli, 52, and Filippo Norelli, 17 -- all were from near Bologna, Italy, according to Italian news agency ANSA and other reports.
"The trip was a gift from one of Norelli's sisters to mark the 25th anniversary of his marriage," Giovanni Leporati, a friend of the Norelli family, told the AP by phone. "The anniversary already happened but they took advantage of the August holidays and went."
By choice or chance, other Italian tourists narrowly missed boarding the flight and survived, ANSA reported: Silvia Rigamonti, Michele Norelli's wife and Filippo's mother, chose not to take the tour, and a third family booked on the trip -- Paola Casali, 42, of Rome, and her son Lorenzo, 13 -- did not arrive in time.
The aircraft were operating in an area over the river that is outside the supervision of air traffic controllers. Aircraft must stay below 1,100 feet and are required to avoid each other.
The National Transportation Safety Board had local investigators and a team from Washington, D.C., on the scene investigating the crash Sunday.
"It would appear that the airplane ran into the back side of the helicopter," New York Mayor Michael Bloomberg said Saturday. "But keep in mind with all of these things that, number one, until the National Transportation Safety Board [NTSB] makes the determination, nothing is a fact."
He said an NTSB investigation could take weeks or years.
"We won't be determining a probable cause of this accident while we're on scene," Hersman noted.
Investigators Probe What Went Wrong in Crash
Officials were studying photos and data related to the accident and trying to locate additional photos and video.
"We have human performance, maintenance, operations, air traffic control -- we are looking at everything," Hersman said. "Nothing has been ruled out at this point in time. Our investigations are very comprehensive."
NTSB records show Liberty Helicopters has had eight previous accidents and one "incident" since 1995 with no fatalities, Hersman said. Two accidents and an incident were reported last year.
Earlier, appearing on ABC News' "Good Morning America," Hersman said investigators would re-examine how safe tourist helicopters are.
"We've looked at air tour operations in Hawaii, in Alaska, near the Grand Canyon, other places," she said. "We have made recommendations. But I think for this accident we need to see what the facts tell us before we come to any conclusions."
This evening, Hersman offered some new details on the two aircraft.
The seven-seat helicopter was built in 1997, she said. The left-front seat was the pilot seat. There was a right-front bench for two passengers and rear bench for four passengers. Emergency floats on the skids needed to be deployed manually. The pilot was hired in 2008 with 1,800 flying hours and had since flown 900 additional hours, for a total of 2,700 hours. The most recent "check ride" of the aircraft was in February.
The Piper Lance airplane had six seats, including one for the pilot, Hersman said. The flight originated in Winfield, Pa., at 7:14 a.m., stopping at Teterboro Airport, where it was cleared for takeoff at 11:49 a.m. At 11:52 a.m., there was an electronic handoff from Teterboro to Newark, but Newark couldn't establish direct contact.
"Teterboro attempted to contact the aircraft with no result, and shortly thereafter the aircraft was lost," Hersman said.
The plane's last radar blip was at 1,100 feet at 11:53:14 a.m.
Eyewitnesses to the Fatal Crash
There were dozens, perhaps hundreds of eyewitnesses to Saturday's crash, which occurred on a warm, clear summer day.
"I saw a puff of smoke," Alanna Duffy told ABC News Radio after seeing the accident from a New York pier. "And then the helicopter did a couple of twists and turns, and rotors started flying. And then the nose of the helicopter went straight down into the water."
Immediately afterwards, a debris field, including a fuel slick, spread across the Hudson River, much of it toward the New Jersey side. Debris, including a wheel, washed up in New Jersey.
Police initially set up a security cordon both north and south of the crash site, located just south of 14th Street. Within minutes, divers and vessels attempted to rescue occupants of the submerged aircraft. Later, a large crane on a barge moved toward the debris field.
"This is not going to have a happy ending like when the Airbus went down on the river where everybody survived," Bloomberg said Saturday afternoon, referring to the case in January when a disabled passenger plane landed safely on the Hudson. "In this case, we believe nobody has [survived]."
ABC News' Richard Esposito, Howard Price, Fabiola Antezana and Dan Gura contributed to this report.