> our title:

Broken Shaft Caused Predator Crash

> original title:

MQ-1B Predator Accident Report Released

(Source: US Air Force; issued March 16, 2012)

LANGLEY AIR FORCE BASE, Va. ---- A broken variable pitch propeller quill shaft caused the crash of an MQ-1B Predator Aug. 20, 2011, in Afghanistan, according to an Air Combat Command Accident Investigation Board report released today.

According to the report, the broken quill shaft forced the aircraft's propeller to an abnormal angle, generating increased drag and causing the aircraft to rapidly descend. By the time the mission control element pilot was able to diagnose the emergency, take action, and hand off the aircraft to the launch and recovery element, the aircraft had lost too much altitude and was unable to reach the forward operating base.

The mishap sensor operator identified an alternate location in a rural, unpopulated area; however, due to the rapid descent rate, the aircraft crashed in a civilian residential area before reaching the designated landing site.

During the investigation, the board president also determined the lack of Air Force maintenance guidance defining the serviceable life of the quill shaft resulted in exceeding the manufacturer's defined serviceable life, and the quill shaft breaking due to fatigue.

The aircraft, one air-to-ground Hellfire missile and one missile rail were destroyed on impact. Two civilian residential structures were also damaged. The damage was assessed at approximately $3.9 million. There were no injuries or damage to other government or civilian property as a result of the mishap.