Air Force officials release Reaper accident report Published July 13, 2009 LANGLEY AIR FORCE BASE, Va. (AFNS) -- Air Force officials here announced an MQ-9 Reaper that crashed March 20 at Fort Irwin, Calif., was due to an improperly assembled oil system temperature control valve, according to an Air Combat Command Accident Investigation Board report released July 13 here. The Reaper, assigned to the 42nd Attack Squadron at Creech Air Force Base, Nev., was damaged upon landing and has an estimated repair cost of $3.9 million. There were no injuries or damage to other property or equipment. According to the report, during a training mission the pilot received an engine malfunction warning and shortly thereafter lost power and torque. During an emergency landing to a simulated airfield on a field comprised of loose earth graded to look like a runway, the Reaper overshot the intended field and landed on unimproved, uneven desert terrain with scrub bushes. The findings of the accident investigation board indicate that even if the Reaper had landed on the emergency airstrip, it would have sustained a similar degree of damage. The cause of the mishap was an improperly assembled oil system temperature control valve. The incorrect assembly caused the valve to fail in such a way that there was a severe oil flow imbalance that resulted in engine failure.