Data retrieved from an investigation into a collision last week between an American Airlines regional passenger jet and a US Army helicopter over the Potomac River in Washington that killed 67 people will be released today, National Transportation Safety Board Chair Jennifer Homendy said.
"We have much more granular data from Potomac Tracon that we're going to be able to release," Ms Homendy said, referring to a Federal Aviation Administration terminal radar approach facility in Virginia.
The Army Corps of Engineers today began lifting the wreckage from the river, which officials have said could take a week or longer.
Wreckage is being moved to a hangar at Washington Reagan National Airport. Much of the Potomac River remains restricted to authorised vessels.
Two of the lesser-used runways at the airport remain closed.
Ms Homendy said the NTSB also plans to look at prior near-miss incidents between helicopters and airplanes around Washington Reagan and could expand the investigation "to other areas where's there's military helicopter and air traffic".
She said the NTSB could complete interviews with air traffic control personnel today and is conducting interviews with American Airlines and the US Army on the operations side.
"We're going to have to understand what are standard operating procedures" for a helicopter training mission, she said.
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Investigators from the NTSB said on Saturday that they had determined that the CRJ-700 airplane was at 99 metres, plus or minus 8 metres, at the time of impact.
The new detail suggests that the Army Black Hawk helicopter was flying above 61 metres, the maximum altitude for the route it was using.
Ms Homendy said that data was from DC radar that updates every five seconds, and "that can change in a quick period of time when the helicopter is moving at a good speed".
Data confirmed that the air traffic controller alerted the helicopter to the presence of the CRJ-700 about two minutes before the crash.
The Washington DC fire department said yesterday that officials had positively identified 55 of the 67 people killed in the collision.
Meanwhile, relatives of some of the victims visited the edge of the river near the crash site yesterday.
