LANGLEY-EUSTIS, Va. --- A mechanical failure leading the engine to overheat caused the crash of an MQ-1B Predator Oct. 19, 2015, according to an Abbreviated Accident Investigation Board report released today.
The aircraft was conducting a surveillance mission in support of Operation Inherent Resolve at an undisclosed overseas location at the time of the mishap. There were no injuries or damage to civilian property as a result of the mishap and all wreckage was recovered.
The board president found, by a preponderance of evidence, that the cause of the mishap was a pinhole leak in the elbow radiator of the coolant supply line. Maintenance personnel did not detect that the coolant supply line and a different line had been placed too close to each other, resulting in rubbing, chafing, and the pinhole leak.
The loss of coolant inadvertently resulted in increased fuel flow, further degrading engine performance. The aircraft was operated by personnel from the 20th Reconnaissance Squadron, Whiteman Air Force Base, Missouri. The loss of the aircraft was valued at approximately $4.66 million.
According to the report, the mishap crew attempted to return the aircraft to base after noticing abnormal engine temperatures but was unable to maintain the aircraft’s safe altitude in a mountainous region. Despite implementing recovery procedures, there was no change to the overheat condition, and the aircraft continued to fly at a lower altitude. Once it was determined that the aircraft would be unable to successfully return to base, the crew executed a forced landing in an unpopulated field.