> our title:

Faulty Propeller Caused Predator Crash

> original title:

MQ-1B Predator Accident Report Released

(Source: US Air Force; issued March 21, 2013)

LANGLEY AIR FORCE BASE, Va. --- An MQ-1B Predator propeller malfunction led to the crash of the aircraft in a non-residential area in Afghanistan Oct. 26, 2012, according to an Air Combat Command abbreviated accident investigation board report released March 13.

The mishap crew and mishap remotely piloted aircraft were assigned to the 432d Wing at Creech Air Force Base, Nevada. When the accident occurred, the crew was flying a surveillance mission out of Jalalabad Air Base, Afghanistan.

According to the report, the crew received a high temperature caution message, indicating a problem with the variable pitch propeller, roughly 10 hours into the mission. Eventually, the propeller failed in a manner that only allowed movement to a lower propeller-pitch angle.

While attempting to resolve the problem, the mishap pilot momentarily commanded the propeller pitch to an angle that produced reverse thrust, and the system would not accept commands to return the propeller to a higher pitch angle. The resulting loss of forward thrust prevented the aircraft from returning to base. The pilot was then directed to crash the aircraft because it would not be able to reach a suitable landing location.

The accident investigation board president found by clear and convincing evidence, the cause of the mishap was a combination of mechanical failure of the propeller motor and unnecessary movements of the propeller pitch control lever by the mishap pilot. Additionally, the board president found by a preponderance of evidence that incorrect and insufficient checklist guidance, reinforced by incorrect simulator training, substantially contributed to the mishap.

The aircraft and one air-to-ground AGM-114 Hellfire missile were destroyed on impact. The loss is valued at approximately $4.6 million. There were no injuries or damage to government or private property.