The U.S. Air Force has completed its investigation into the July 21, 2008, crash of a B-52 30 miles off of the U.S. island of Guam in which all six crew members were killed.

Wreckage showed the bomber's stabilizer trim setting was set in a 4.5-5 degree nose-down setting when the aircraft impacted. However, investigators were unable to identify the cause for the incorrect setting, citing the absence of survivors, voice communications or other clues from the aircraft instruments. Still, despite the lack of data, the investigators note that there was "clear and convincing" evidence the faulty trim stabilizer trim setting was the cause for the aircraft loss.

Contributing to the accident was the combination of the aircraft's low altitude with a descending left turn, as well as the fact that the crew was late to recognize the seriousness of the situation. But accident investigators were careful to avoid placing much blame on the crew, noting that "even an experience aircraft could have found it difficult to recognize, assess and recover from the very rapidly developing situation involving the stab trim setting."

Raider 21 belonged to the 20th Bomb Squadron, 2nd Bomb Wing, and was normally based at Barksdale Air Force Base, La. It was deployed to Anderson AFB on Guam as part of the Air Force's routine bomber presence there. The aircraft was on a training mission and was getting ready to participate in Guam Liberation Day festivities.

The USAF accident investigation report can be found online with a link at AviationWeek.com/ares.

Photo: USAF