All 67 people on board the plane and the helicopter were killed.
An American Airlines regional jet went down in the Potomac River near Washington, D.C.'s Ronald Reagan Washington National Airport after colliding with a U.S. Army Black Hawk helicopter on Wednesday night, with no survivors.
Sixty-four people were on board the plane, which departed from Wichita, Kansas. Three soldiers were on the helicopter.
The collision happened around 9 p.m. when the PSA Airlines Bombardier CRJ700 regional jet was on approach to the airport.
NTSB investigator J. Todd Inman said that the Army copter was on a training mission and it would utilize night vision goggles.
"We do not know at this time if the night vision goggles were actively being worn," he said.
The NTSB said that the air traffic controller alerted the helicopter crew about the American Airlines plane about two minutes before the crash, based on the data they have collected.
NTSB investigator J. Todd Inman said the Black Hawk was flying at an altitude of 325 feet at the time of the collision, based on the preliminary data they have collected.
The tower cab data showed 200 feet near the time of the accident, according to Inman. There is a 200-foot ceiling for helicopters in that corridor above the Potomac River.
The investigator said more info needs to be collected to determine the discrepancy.
J. Todd Inman, an NTSB investigator said there were five air traffic controllers working at the tower during the time of the collision.
At this time NTSB has interviewed three of the five employees and plans to interview the other two members by Monday, he said.
"This is a controller's worst nightmare,' he said. "These interviews take a long time."
