An MQ-1B Predator, left, and an MQ-9 Reaper taxi to the runway June 13 in preparation for takeoff at Creech Air Force Base, Nev. (Airman 1st Class Christian Clausen/Air Force)
A coolant problem that triggered a loss in fuel ultimately brought down an MQ-1B Predator in January as it was flying a mission in the Mediterranean Sea, the Air Force announced today.
The Predator, flown by the 18th Reconnaissance Squadron at Creech Air Force Base, Nev., was destroyed in the Jan. 17 crash at a loss of almost $4.6 million.
The aircraft took off from a forward operating location at almost midnight GMT on Jan. 16 for an intelligence, surveillance and reconnaissance mission in the area of the Mediterranean Sea. During pre-flight, ground crew members noticed fuel draining from the aircraft but determined it was water and cleared the Predator for the mission.
The aircraft flew for more than 10 hours and three crew changes before the fourth crew took control at 8 a.m. GMT on Jan. 17. Two hours later, as the aircraft was flying at about 14,000 feet, the crew noticed a sudden change in engine temperatures, which were indicative of a coolant failure. The failure caused a significant loss of thrust and the Predator began to descend, according to an Air Force Accident Investigation Board report on the mishap.
As the crew began to divert to the closest suitable airfield about 400 miles away, the drone’s aircraft digital control system increased fuel flow as commanded by its engine cold enrichment software. The system mistakenly interpreted the engine temperature as a “ground cold start situation” and the increased fuel-to-air mixture reduced thrust to the point that the drone could not stay aloft. It crashed into the sea at about 11:32 GMT. The crash report doesn’t say if the wreckage was recovered.
The crash happened five months after a similar incident in which an MQ-1B crashed into the Mediterranean after flying a 20-hour ISR mission in Africa. That crash was caused by a failed power converter, according to a report on that mishap.