area. Unfortunately, problems with the ground-based laser designator caused them to miss their assigned targets. They saw their first really successful combat trials during Operation Prairie Fire in 1986, a series of confrontations between the U.S. Navy and Libya in the Gulf of Sidra. During the famous 'Line of Death' confrontations, USN A-6Es used Paveway II-series bombs to help destroy/disable several Libyan patrol boats. Later, they were used during Operation Eldorado Canyon, the joint April 1986 USAF/USN/ USMC raid on Benghazi and Tripoli.
One of the Paveway II configurations, the diminutive 500 lb./227.3 kg. GBU-12, proved to be one of the most important weapons of the 1991 Persian Gulf War. In late January and early February of 1991, CENTAF BDA teams showed that the 'battlefield preparation' in the KTO (Kuwaiti Theater of Operations) was not destroying enough armored vehicles and artillery pieces with standard LDGP bombs to meet the proposed attrition target of 50 % prior to the start of the ground war.
To help overcome this problem, Major General Buster Glosson, the CENTAF Director of Operations, came up with an idea called 'tank plinking.' General Charles A. Horner, the commander of CENTAF during the war, is said to have been told by the commander of CENTCOM, General H. Norman Schwarzkopf, to
Here is how tank plinking worked. A flight of F-111Fs or F-15Es would fly over an Iraqi artillery or armored unit shortly after sunset. Since the sand of the desert cooled faster than the military equipment dug in among the dunes, the vehicles and artillery tended to show up as 'hot spots' in the aircraft's FLIR targeting systems. They would then drop one of the 'old' GBU- 12s on the desired target, and the results were, in a word, spectacular. Despite what you might think, even a main battle tank cannot have armor everywhere, especially on top. Thus, when one of the 'little' LGBs hit one, the target would go up in flames, and the BDA assessments were quite positive. The fact that an F-111F might carry four GBU-12s, and an F-15E up to eight, meant that tank plinking was a surprisingly economical way of killing targets up in the KTO. Every night, for several weeks in early February 1991, the 4th and 48th TFWs would send pairs of F-15Es and four ship flights of F-111Fs into the KTO to hunt artillery and armor targets. The results were spectacular. Often, the small formations would come home with anything from twelve and sixteen targets killed per mission.
Combined with the capabilities of an integrated thermal imaging/laser designation/weapons delivery system, the Paveway II-series LGB was a formidable weapon when properly employed. Formidable, but very limited. Paveway II still had a very small launch 'basket,' which diminished its utility in high-threat environments. In particular, its low-level capabilities were highly restrictive, making its utility in that mode marginal. Even with drops from 20,000 feet/6,096 meters, the favored altitude for Paveway II drops, there were challenges for the crews.
Even before Paveway II went into combat, the Air Force and TI had begun to develop the replacement for the Paveway II under a program called the Low-Level Laser-Guided Bomb (LLLGB). Begun in 1981, it was designed to overcome the shortcomings inherent in the previous Paveway II bombs and take full advantage of the new series of laser designator systems being deployed worldwide. The result was the Paveway III series of bombs, which came into service in the mid-1980s.
The key was to be an all-new guidance section, which would be equipped with a microprocessor-controlled digital autopilot adaptive to the flight and release conditions. There are a variety of settings for delivery aircraft, flight mode, warhead configuration, laser coding, and delivery profile. Even more important, with a change of the Programmable Read Only Memory (PROM) chips which hold the autopilot software, the basic guidance package can be adapted to a variety of bomb configurations and capabilities. The changes to Paveway III start at the front of the seeker with the seeker dome, which is made of Lexan plastic with a fine wire mesh. Inside this dome is an optics housing containing a four-quadrant laser sensor and optics to focus the spot of laser light from the laser designator. The simple four-quadrant detector in the seeker is the touchstone of the Paveway program's simplicity, and is one of the keys of its success. And the sensitivity of the seeker itself has also been improved, so that even low-power laser designators (or standard designators degraded by weather) can be used. The seeker housing is gimbaled in two axes, and can scan in a bar (horizontally, back and forth), box (rectangular), or conical (circular) mode. Aft of the seeker is the guidance electronics section, which contains the autopilot, laser decoding, and signal processing circuitry, as well as the rotary switches for programming the bomb. The control setting switches are mounted flush with the exterior of the airframe, and can be set with almost any flathead tool, though the 'ordies' (ordnance technicians) from the 391st Fighter Squadron at Mountain Home AFB (they fly the F-15E Strike Eagle) tell me that a quarter works best for this job.
The laser seeker, guidance electronics, and control section form what is termed the Guidance and Control Unit (GCU), which is attached to the front of the selected warhead. Paveway LGBs have always made use of standard USAF munitions as the warhead; and Paveway III is no exception. It can be attached to any of the 80- series bombs, as well as the BLU-109/B penetrating warhead. At the rear of the warhead is mounted the cruciform airfoil group. This is a tail section equipped with four pop-out wings to help stabilize the weapon during its flight. Along with mounting lugs for the bomb rack on top of the weapon, this is the makeup of a complete Paveway III LGB.
The first production versions of the Paveway III were the GBU-24 family, which entered service in the mid- 1980s. Designed as the general purpose LGB, the GBU-24 quickly became the primary weapon of the F-111Fs of the 48th TFW at RAF Lakenheath. It is the airfoil group, with its large spring-deployed planar wings, that makes all the difference in expanding the launch and delivery envelope of the GBU-24. When the wings are fully extended some two seconds after the bomb is dropped, they have twice the lift area of the Paveway II-series airfoil group, and give the GBU-24 a glide ratio of 5:1, meaning that for every foot/meter of altitude lost in flight, the bomb can travel forward five feet/meters. This means that the launch envelope for the GBU-24 is vastly greater than the Paveway II-series bombs, and gives it the energy and maneuverability for a lot of tricks.
The second version of the GBU-24 family, while a bit different, became one of the stars of Desert Storm. This variant has a BLU-109/B penetrating bomb warhead, designed to punch through heavy reinforced concrete and armor. Called a GBU-24/B, it was Saddam Hussein's greatest nightmare, and his worst tactical surprise when Desert Storm kicked off. With the exception of a handful of command bunkers outside of Baghdad, it was capable of destroying every hardened target in Iraq. This included the Yugoslav-built hardened aircraft shelters (HASs) that had been previously thought to be impervious, even to a near-miss by a tactical nuclear device! The GBU-24/B is composed of the same components as the basic GBU-24/B, with the difference of the BLU-109 being substituted for the Mk 84. In addition, there is a spacer attached to the bomb body called an ADG-769/B Hardback. This helps maintain the same tail clearances as the larger-diameter Mk 84. In addition, there is only one fuze, an FMU-143/B delayed action unit mounted in the rear of the BLU-109/B. Other than that, the two models are identical, with the necessary software to operate both models already being built into the common guidance and control unit. A third variant, the GBU-24B/B, is an improved GBU-24A/B.
The fourth variant of the Paveway III family is a unique version for the F-117A Nighthawk Stealth Fighter, the GBU-27/B. The reason for this is that the F-117A design was frozen before the new bomb was even in design, and the Lockheed designers had originally assumed that they would only have the older Paveway II-series weapons with their relatively small airfoil groups to fit into the weapons bays of the F-117s. With the coming of the Paveway III- series weapons, though, the USAF wanted to get the new bombs, especially ones equipped with the BLU-109/B, onto the new stealth birds. The problem was that the BSU-84/B airfoil group was too large to fit into the Nighthawk's weapons bays. This problem was overcome when the TI and Lockheed designers realized that the F- 117A was almost never going to fly the kind of low-level delivery profiles that the F-111Fs and F-15Es were going to. In fact, the Nighthawk normally flies its weapons delivery profiles straight and level at various altitudes, dropping its precision weapons under the control of the pilot. Thus, the TI designers came up with a slightly different version of the fin group used on the Paveway II family, which fits nicely inside the limited volume of the F-117A weapons bay. The normal warhead of the GBU-27/B is the BLU-109/B, though the Hardback adapter is deleted because of the unique 'trapeze' weapons handling gear of the Nighthawk.
The final version of the Paveway III family deserves special attention. It is the famous 'Deep Throat' super
