Incident Overview
Aircraft on a night instrument flight rules (IFR) flight from Washington's Dulles Airport to Roanoke, Virginia, encountered a downdraft during a visual approach to Runway 24.
Sequence of Events
The pilot reported that from an altitude of 5,000 feet on a right base leg, they were cleared for a visual approach to Runway 24. The pilot advised the tower that all terrain was in sight and noted that the Automated Terminal Information Service (ATIS) indicated a 25,000-foot overcast with 15 miles visibility.
At a distance of 6.2 nautical miles from the runway (as measured by LORAN C), the aircraft encountered a downdraft and struck the top of a tree on a mountain ridge. The pilot maintained control of the aircraft and subsequently landed on Runway 24.