November 14, 2012: The U.S. Air Force is continuing to upgrade its fifty year old B-52s. The latest upgrade will enable each B-52 to carry over 110 of the 130 kg (285 pound) Small Diameter Bombs (SDB, also known as the GBU-39/B). Six years ago the rotary bomb rack inside the B-52 was modified to carry 32 SDBs instead of 15 larger bombs.
The SDB was designed from the bottom up as a smart bomb. The SDB has a more effective warhead design and guidance system. Its shape is more like that of a missile than a bomb (nearly two meters, as in 70 inches, long, and 190mm in diameter), with the guidance system built in. The smaller blast from the SDB resulted in fewer civilian casualties. Friendly troops can be closer to the target when an SDB explodes. While the 500, 1,000, and 2,000 pound bombs have a spectacular effect when they go off, they are often overkill. The troops on the ground would rather have more and smaller GPS bombs available. This caused the 500 pound JDAM to get developed quickly and put into service. But it wasn't small enough for many urban combat situations. The SDB carries only 17 kg (38 pounds) of explosives, compared to 127 kg (280 pounds) in the 500 pound bomb. The SDB is basically an unpowered missile, which can glide long distances. This makes the SDB even more compact. The small wings allow the SDB to glide up to 70-80 kilometers (from high altitude). SDB also has a hard front end that can punch through nearly three meters (eight feet) of rock or concrete and a warhead that does less damage than the usual dumb bomb (explosives in a metal casing). The SDB is thus the next generation of smart bombs. The more compact design of the SDB allows more to be carried. Thus F-15/16/18 type aircraft can carry 24 or more SDBs. The SDBs are carried on a special carriage, which holds four of them. The carriage is mounted on a bomber just like a single larger (500, 1,000, or 2,000) pound bomb would be. However, this feature was rarely needed in combat situations.
This makes the B-52 even more effective as the cheapest to operate and most reliable "bomb truck" the air force has. With a max takeoff weight of 240-250 tons the BUFF (Big Ugly Fat Fellow) is basically a large aircraft designed to carry bombs cheaply and efficiently. Last year the readiness rate of these bombers was 78 percent. Although a half century old, most of the internal gear has been replaced with modern electronics and furnishings. It’s all flat screens and modern gear. Look closer and you see fifty year old metal.
The B-52 is the cheapest to operate heavy bomber in the air force and one of them can cover all of Afghanistan. These B-52s are based on the Indian Ocean island of Diego Garcia and from there supported operations in Iraq and Afghanistan. In late 2001, ten B-52s dropped a third of the bomb tonnage in Afghanistan. That's a remarkable record for a 60-year-old aircraft design. The B-52 carried that much of the load because it's the most cost-effective heavy bomber we have. The B-52 also has a lower accident rate than the B-1 and B-2. Compared to the supersonic B-1 and high-tech B-2, the B-52 is just a flying truck. Thus the B-52, despite its age, was the cheapest, safest, and most reliable way to deliver smart bombs over Afghanistan.
Over Afghanistan, carrying a dozen 909 kg (2000-pound) JDAM (GPS-guided bombs) or a larger number of smaller bombs, a B-52 could circle a combat area for hours, waiting for the special forces guys or Air Force controllers on the ground to send them the coordinates of a target. The JDAM landed (over 90 percent of the time) within 16 meters (50 feet) of the location the ground troopers wanted it. Better yet, most of the bombs arrived within ten minutes of the request.
The B-52 was the principal heavy bomber throughout most of the Cold War (1947-91). The B-52 prototype first flew in 1952. The last one built, a B-52H, was in 1962. The B-52 has seen a lot of action in Vietnam, the Persian Gulf War, in the Balkans, and over Afghanistan. It has a crew of five (pilot, copilot, navigator, electronics warfare officer, and radar navigator). There used to be a gunner for a rear-firing 20mm cannon but this was eliminated in the 1990s. Automation can reduce crew size even more. The 1970s era B-1 has a crew of four, and the 1980s era B-2 has a crew of two. The only B-52s flying are the B-52H model, which has been much modified since the last one rolled off the assembly line in 1962.
A true replacement for the B-52 was never built because no one foresaw the development of such accurate smart bombs and the ability of the U. S. Air Force to destroy most anti-aircraft defenses. Indeed, even when faced with heavy defenses, the B-52 was able to fight its way through. During the twelve days of Linebacker II raids against North Vietnam in 1972, 15 B-52s were shot down by Soviet-built SAM-2 missiles. The 150 B-52s stationed in Guam flew 729 missions, for a loss rate of two percent. But because of the number of sorties flown, ten percent of the B-52s involved were brought down. Of the 92 airmen in the downed aircraft, 33 died.
After Vietnam the B-52s received several generations of new electronic warfare equipment, learning much from the experience during Linebacker II. But there never was enough money to keep the B-52 completely up to date, especially with the equipment needed to use some of the newer bombs. As a result, some B-52s got their JDAM equipment just before the 2001 war in Afghanistan. The B-52 was upgraded to use JDAM before the B-1B because the B-52 is more reliable. In any event, the upgrade was cheap - wiring from the weapons officer's station to the bombs so GPS location data could be changed in flight. The 50-year-old B-52 soon became the weapon of choice over Afghanistan, able to hang around for hours and drop one-ton JDAM bombs on demand.
Currently, the Air Force has the capacity to shut down the high-altitude missile systems of just about anyone and then bring the B-52s in at high altitude to avoid low-altitude anti-aircraft guns and mobile antiaircraft missile systems. The B-1 and B-2 were built to deal with even more intense antiaircraft defenses. But with the collapse of the Soviet Union in 1991, no one else has such a system. Perhaps, in the future, a nation like China may build another such formidable antiaircraft defense system. For the moment, because of the lack of first rate air defenses to stop it, the B-52 can still hack it in the combat zone, even delivering nuclear weapons.