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B-2 Felled By Sensor Problem: As we reported in May, faulty readings in air data sensors caused the Feb. 23 crash of a B-2 bomber taking off from Guam, the service’s accident investigation board president said June 5. Announcing the AIB’s findings to reporters via teleconference, Maj. Gen. Floyd Carpenter, vice commander of 8th Air Force, said moisture got into three of the B-2’s 24 air data sensors, also called pitots, which detect air pressure and derive information such as altitude. The moisture threw off the accuracy of the sensors, which then disagreed with readings taken by the other 21, and the aircraft’s computers recommended a recalibration. A procedure that would have evaporated the moisture and made the recalibration more accurate—switching on heaters in the system—wasn’t used, Carpenter said. However, the procedure wasn’t official; it was passed from one technician to another verbally, and the airman performing the recalibration that day wasn’t aware of it. Carpenter said that, when the aircraft began its takeoff roll, the faulty data fooled the bomber into thinking it was actually pitching down and going faster than its actual speed of 130 knots. To recover, it made an uncommanded pitch up of about 31 degrees, and got about 80 feet off the ground before stalling and rolling left. When the left wingtip touched the ground, the two pilots ejected, safely. Carpenter said the two pilots “acted as they should have” and dealt with the situation and some momentary cockpit warnings as they were trained to do. He also said the technician who did the calibration probably wasn’t to blame because he wasn’t required to know of the pitot heat procedure. The air data sensor problem had manifested just once before, in 2006, and also at Guam. But because it was so rare, the pitot heat procedure wasn’t added to the technical manual. It has now been added, along with a number of additional inspections. Carpenter said the AIB saw no inherent flaw in the B-2’s design or flight controls.