Despite strenuous efforts to change the situation the U.S. Air Force is still stuck with an annoying readiness rate (percentage of available aircraft able to do their job) problem. In short, the half century old B-52s have a readiness rate of 75 percent while the more recent B-2s have a rate of only 46 percent. Actually the situation has gotten worse. Four years ago the rate for the B-52 was the same but the B-2 rate was 55 percent.
Age has less to do with it than you might think. The B-2 has lots of stealth stuff, but the air force has overcome a lot of those problems. Meanwhile, the ancient, but relatively simple, B-52 has the highest readiness rate, and is the cheapest to operate. The U.S. Air Force has been struggling with B-2 readiness since the aircraft entered service in 1997. For example, back in 2007 the air force revised the maintenance contract (with the aircraft's manufacturer) for its 21 B-2 bombers to include an availability (percentage of aircraft available for combat) guarantee. Even then the B-2 was known to be notoriously difficult and expensive to maintain. The availability percentage guarantee was not revealed. For a long time the B-2 was known as a "Hanger Queen" (an aircraft that spends too much time in the hanger for maintenance or repairs). The air force has been eager to change this. Before this 2007 deal the air force admitted that B-2 availability was usually less than 50 percent. In 2006 it became known that only about seven of the U.S. Air Force's 21 B-2 bombers were ready to go at any time. In addition to the availability guarantees (which apparently did not work) the air force also tried a combination of robots, sprayers and quality control which were more successful, but still short of the goal of doubling the B-2 readiness rate.
In 2004 the U.S. Air Force introduced the use of robots to help with maintenance. The big problem was that the B-2 uses a stealth (anti-radar) system that depends a lot on a smooth outer skin. That, in turn, required that the usual access panels and such on the B-2, be covered with tape and special paste to make it all smooth. 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 a 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) was then about 35 percent, which was less than half the rate of most other aircraft. This meant, that whenever there is a crises that requires the attention of B-2s, there were not many of these bombers ready to fly.
The main base for B-2s is in Missouri, and over a thousand maintenance personnel were assigned to take care of 19 aircraft there. That was where a team of four robots was installed, to apply the 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. At that point the quality control problems were thought to be solved although the readiness rate of B-2s rarely got over 50 percent.
B-2s still require 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 twice that of the B-52.
If stealth is not an issue (as when there is 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 its 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.