A member of the US National Transportation Safety Board, Mark Rosekind, spoke at a briefing Wednesday.
Rosekind said engine monitors and GPS navigation equipment may have stored useful information.
He also said winds may have been a factor. A weather reporting station at nearby LaGuardia Airport had reported gusts of up to 23 mph (37 kph).
Rosekind said one of the helicopter's main blades was broken. But it's not clear whether it broke before or after it crashed. The man at the helm of the helicopter that crashed into the East River, killing one British passenger and injuring a British couple and a New Zealand woman, was an experienced commercial pilot who owns a company that manages a local airport.
Investigators are still trying to determine why the helicopter went down shortly after takeoff from a riverbank heliport.
Emergency crews arrived within seconds of Tuesday's crash to find the helicopter upside-down in the murky water with just its skids showing on the surface.
The pilot, Paul Dudley, and three passengers were bobbing, and witnesses reported a man diving down, possibly in an attempt to rescue the remaining passenger.
New York Police Department divers pulled Sonia Marra, 40, from the water about 90 minutes after the Bell 206 Jet Ranger went down at around 3:30 p.m. She was pronounced dead at the scene.
Meanwhile, a portrait emerged of the pilot as an expert flier who once landed a plane in a field near Coney Island after its engine failed. Dudley owns Linden Airport Services, the company that manages the Linden, New Jersey, municipal airport under a 20-year contract with the city, Linden Mayor Richard Gerbounka said.
Pilot Owen Kanzler, who said he has known Dudley for at least 20 years, said he saw Dudley's helicopter take off from the airport around 3 p.m. Flight conditions were calm, he said, with fair weather clouds above the altitude where Dudley would have been flying.
"As long as I've known Paul, he's owned and flown helicopters," he said.
The passengers were friends of Dudley's family and were visiting New York to celebrate the birthdays of Marra and her stepfather Paul Nicholson, 71. He was on the chopper along with his wife Harriet, 60; and a friend of Marra's, Helen Tamaki, 43. The Nicholsons are British but live in Portugal; Marra and Tamaki, a citizen of New Zealand, lived in Sydney, Australia. The group had planned to do some sightseeing and then go to dinner in Linden, police said.
