The Northrop B-2 in maintenance is as fascinating as it is in flight. I saw one during the maintenance process, which typically lasts at least a full year. In this USAF photograph a technician is working on the fuselage above the cockpit on a skinned-down version. The B-2 awaits a number of applications including the final layer of radar-absorbent materials, which look like a thick coat of rubber.
The B-2 Spirit is also known as the Stealth Bomber because of its low observable stealth technology. The aircraft is stealthy due to a handful of factors, including the carbon-graphite composites used in the structure, the various material applications, the angles of the flying wing design, and certain maneuvers that make it difficult for the aircraft to be identified by radar.
The USAF operates 20 B-2s. The original procurement was for as many as 132 aircraft, but the collapse of the Soviet Union in the early 1990s put a huge dent in the program. The prototype was converted, bringing the number to 21. However, a crash in February, 2008, of the Spirit of Kansas after taking off from Andersen AFB in Guam brought the number back to 20. The crew in that accident escaped. The probable cause was determined to be moisture in the B-2’s Port Transducer Units during air data calibration, which sent distorted information to the air data system. As a result flight control computers calculated inaccurate air speed and a negative angle of attack, which caused the B-2 to pitch upward 30-deg. during takeoff..
(Information on the cause of the crash comes from a comprehensive report on the B-2 in Wikipedia.)
There are 80 pilots qualified to fly the B-2s. What a crew of lucky airmen! 
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