Aircraft maintenance accident investigation board complete Published Feb. 5, 2007 SCOTT AIR FORCE BASE, Ill. -- Air Mobility Command today released the results of its investigation into the June 1, 2006, mishap involving an engine test on a C-32A aircraft at Andrews AFB, Md., during which asphalt from the shoulder pavement disintegrated and impacted the aircraft. The Accident Investigation Board, convened by AMC, concluded the primary cause of the mishap was the improper placement of the aircraft, with the tail of the aircraft over the asphalt. The mishap occurred as the engine run team was retarding the engines following the test, at which time an approximately 8' x 13' patch of shoulder asphalt separated from the ground, broke apart, and portions of the asphalt impacted the aircraft. The AIB determined a substantially contributing factor to the accident was the lack of knowledge on the part of the engine run team of the potential risks associated with high power jet engine thrust on airfield asphalt edge pavements. These risks are caused by the Bernoulli uplift force which comes into play when the air speed over the pavement is high enough to overcome the weight, friction and adhesive properties of the asphalt. No one was injured in the accident although damage to the tail section of the aircraft was significant.