Narrative:

While on short final to the runway; our piper 140 encountered violent rotor wash due to national guard military helicopters maneuvering in close proximity to the active runway. As our aircraft was on short final over the threshold end of the runway; a black hawk helicopter began to lift to a high hover. His call to maneuver was last minute. As a result of the rotor wash; the aircraft became uncontrollable; rolling into an approximate 180 [90] degree bank attitude with near vertical downward descent. Once the plane encountered the rotor wash; there was absolutely no aileron effectiveness to control the aircraft. Cooperating procedures between military and general aviation aircraft would have contributed to the avoidance of such rotor wash encounters.

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Original NASA ASRS Text

Title: A Piper 140 pilot encountered violent rotor wash from military helicopters maneuvering in close proximity to the active runway.

Narrative: While on short final to the runway; our Piper 140 encountered violent rotor wash due to National Guard military helicopters maneuvering in close proximity to the active runway. As our aircraft was on short final over the threshold end of the runway; a Black Hawk helicopter began to lift to a high hover. His call to maneuver was last minute. As a result of the rotor wash; the aircraft became uncontrollable; rolling into an approximate 180 [90] degree bank attitude with near vertical downward descent. Once the plane encountered the rotor wash; there was absolutely no aileron effectiveness to control the aircraft. Cooperating procedures between military and general aviation aircraft would have contributed to the avoidance of such rotor wash encounters.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.