Now, the U.S. Army Corps of Engineers will focus on retrieving the mangled helicopter, a crucial component in federal authorities' probe as they look to confirm data related to its altitude at the time of the collision,

NTSB investigators have recovered the Black Hawk helicopter from a Washington, D.C. collision with an American Airlines airplane from the the Potomac River. Parts of the wreckage are being transported to Ronald Reagan Washington National airport for further examination.