HICKAM AIR FORCE BASE — The Air Force says the first crash of a B-2 stealth bomber was caused by moisture in the sensors that forced bad readings.

The moisture in three of the 24 sensors threw off the preflight data calibrations, which caused the flight control computer to force the aircraft to pitch-up 30 degrees on takeoff. That resulted in a stall and subsequent crash on Feb. 23.

The "Spirit of Kansas," plunged to the ground at Andersen Air Force Base on the island of Guam. It was en route to Whiteman Air Force Base in Missouri, where the 21-plane fleet is based. The crash was the first since the planes' maiden flights nearly 20 years ago.

Both pilots ejected safely.

The Air Force grounded the B-2s and resumed flying them in late April.