April 28,2008: After 53 days of being grounded, the U.S. B-2 bomber is flying again. The bomber was unofficially grounded after one of them crashed shortly after taking off from an airbase on the Pacific island of Guam two months ago [PHOTO]. The B-2 was not officially grounded because it's uncertain what caused the crash. Without that knowledge, there's nothing to fix on the remaining 20 bombers.The air force would not discuss what problems there might have been with the B-2.

The most expensive aircraft ever, each of the 21 B-2s costs over $2 billion (development and construction costs combined). The 170 ton aircraft can carry 22 tons of bombs. There's not a big need for the B-2 at the moment, as the older B-1s and B-52scan deliver bombs cheaper, and just as reliably. Smart bombs have greatly reduced the need for heavy bombers, since one smart bomb can do the job of hundreds of "dumb" bombs. The greater accuracy and reliability of GPS guided JDAM smart bombs means that smaller bombs are now preferred. Thus a heavy bomber can carry over two hundred 250 pound SDB smart bombs. As a result, it's not unusual to only need one heavy bomber over Iraq, or Afghanistan, taking care of all requests from combat troops below.

The B-2 is stealthy, and this would be a major asset in a war against a nation with a decent air defense systems (radars and missiles.) Thus the air force took its time discovering what went wrong with the B-2 on Guam (where four of the bombers were stationed), so that changes can be made to the other B-2s. The stealth aspects of the B-2 make for a very complex aircraft. Not just the tricky radar absorbing skin, but many mechanical and electronic systems as well. That's why the aircraft is so expensive, and you want to take your time trying to figure out what's not working.