BLU-107 Durandal

BLU-107 Durandal weapons are purpose-built for creating craters in concrete, primarily runways. They were developed by the French firm, Matra, which is now part of MBDA, but were purchased by other militaries including the U.S. Air Force, and are often considered the archetype of the rocket-boosted ground penetrating bomb.

The weapon is dropped from an aircraft, and deploys a parachute to stabilize it so can be at a specific orientation to the ground. When it reaches a critical angle, a booster rocket fires and drives the hardened-tip bomb, at high speed, into the concrete. It penetrates the surface and bursts underneath, ideally forming a crater and minimally producing enough debris to prevent an aircraft from using the runway.

Since the Durandal is unguided, the delivery aircraft has to fly a somewhat predictable course, speed and altitude over a runway, easing the job of antiaircraft gunners. Current runway attack munitions, therefore, tend to be standoff laser-guided bombs, delivered from a sufficiently far range to develop considerable speed. They may not, however, reach the same speed as a rocket-boosted weapon.