HONOLULU -- A U.S. Air Force investigation has concluded that the crash of a B-52 bomber off Guam that killed all six crew members last year was caused by a part of its tail in the wrong position.

A report released Friday by the Air Combat Command in Langley, Va., said the plane's stabilizer trim was improperly set between 4.5 and 5.0 degrees nose-down at impact.

The report says the setting indicates the unarmed bomber descended nose-down at low altitude when it crashed in July.

The Command says the reason why the stabilizer trim was improperly set couldn't be determined because there were no survivors, among other reasons.

All but one of the crew members was based out of Barksdale Air Force Base in Louisiana.