A few minutes before landing, air traffic controllers asked the arriving commercial jet if it could land on the shorter Runway 33 at Reagan National and the pilots said they were able. Controllers then cleared the plane to land on Runway 33. Flight tracking sites showed the plane adjust its approach to the new runway.
Less than 30 seconds before the crash, an air traffic controller asked the helicopter if it had the arriving plane in sight. The controller made another radio call to the helicopter moments later: "PAT 25 pass behind the CRJ." Seconds after that, the two aircraft collided.
The plane's radio transponder stopped transmitting about 2,400 feet (732 meters) short of the runway, roughly over the middle of the river.
Video from an observation camera at the nearby Kennedy Center showed two sets of lights consistent with aircraft appearing to join in a fireball.