In 1944, attacking B-17s had to drop roughly 240 tons of bombs, on average, to be sure of destroying one German bridge. Even then, mission success required daylight and fair skies. By 1965, F-4D fighters could destroy a North Vietnamese bridge by dropping 200 tons of unguided bombs. Again, daylight and clear skies were required.
By 1972, however, new Laser-Guided Bombs made possible attacks of previously unthinkable accuracy. The same F-4Ds were suddenly able to drop a span with just 12.5 tons of bombs. This marked a stunning decrease of 95 percent from the World War II standard. Even so, bad weather could still thwart success.
The Persian Gulf War of 1991 marked another advance. Stealthy F-117s, operating at night, required just four tons-that is, four 2,000-pound LGBs-to take out an Iraqi bridge.
Eight years later, during Operation Allied Force, B-2 bombers over Serbia could destroy a bridge with four tons of GPSguided Joint Direct Attack Munitions, in all kinds of weather.
Today, Air Force planners are working on a small diameter bomb weighing a mere 250 pounds. It will carry the explosive power of today's 2,000-pounders.
Source: USAF
