Propeller Failure Cited as Cause in Predator Crash

An MQ-1B Predator crashed May 13 about 13 miles from Creech AFB, Nev., due to a malfunction in the propeller system and the ground crew’s misinterpretation of instrument readings, according to a newly released Air Combat Command abbreviated accident investigation board report. The Predator was participating in a training mission with four separate ground crews from the 11th Reconnaissance Squadron at the time of the crash. The AIB president found “clear and convincing evidence” the cause of the mishap was a variable pitch propeller system failure. “A cable that provides electrical current to the system’s servomotor was found to have produced inconsistent electrical current,” states a Nov. 13 ACC summary of the report. “This lack of electrical power eventually put the aircraft into a thrust deficient situation from which it could not recover.” In addition, aircrews failed to notice the propeller pitch angel remained static over time, checking instead to see if the angle fell within a normal range, states the summary. This contributed to the crews incorrectly assuming the propeller pitch was functioning properly. The MQ-1 and one M-36 training missile were destroyed upon impact—a loss of approximately $4.5 million. (AAIB report; caution, large-sized file.)