Only about seven of the U.S. Air Force's 21 B-2 bombers are ready to go at any time, and now, a combination of robots, sprayers and quality control are trying to double the readiness rate. But for a long time, the B-2 has been known as a "Hanger Queen" (an aircraft that spends too much time in the hanger for maintenance or repairs).
Two years ago, the U.S. Air Force introduced the use of robots to reduce the maintenance efforts required to keep their B-2 bombers flying. The B-2 uses a stealth (anti-radar) system that depends a lot on a smooth outer skin. That, in turn, requires that the usual access panels and such on the B-2 must be covered with tape and special paste to make it all smooth. And after every flight, a lot of this tape and paste has to be touched up, either because of the result of flying, or because access panels had to be opened. All this takes at lot of time, being one of the main reasons the B-2 required 25 man hours of maintenance for each hour in the air. Since most B-2 missions have been 30 or more hours each, well, do the math. The readiness rate of the B-2 fleet (of 21 aircraft) has been about 35 percent, which is less than half the rate of most other aircraft. This means, that whenever there is a crises that requires the attention of B-2s, there are not many of these bombers ready to fly.
The main base for B-2s is in Missouri, and over a thousand maintenance personnel are assigned to take care of 21 aircraft there. A team of four robots were installed, to liquid coating to B-2s, thus cutting maintenance hours in half. But there were quality control problems with the liquid coating, often forcing maintenance crews to go back to tape and paste. Now the quality control problems are thought to be solved, and, if that is the case, the readiness rate of B-2s may go up to 70 percent. Maybe, if everything works out.
B-2s still requires a special, climate controlled hangars. There are some portable B-2 hangers, that can be flown to distant bases, thus keeping the bombers in the air less, and reducing the amount of maintenance needed. B-2 quality hangers have been built at Guam, in the Pacific, and Diego Garcia in the Indian ocean Still, the cost to operate the B-2 is over three times that of the B-52. If stealth is not an issue (not much enemy opposition), than it's a lot cheaper to send a B-52. This is exactly what the air force does most of the time. But in a war with a nation possessing modern (or even semi-modern) air defenses, the B-2s can be very valuable. Costing over two billion dollars each to buy, and very expensive to operate, the B-2s provide that extra edge. No other nation has anything like the B-2s, although many are working on ways to defeat it's stealth and knock them down. Still, when equipped with over a hundred of the new SDB (250 pound, GPS guided Small Diameter Bomb), the B-2 would be a formidable one-plane air force.