Fighter Wing: A Guided Tour of an Air Force Combat Wing tcml-3

by Tom Clancy

  The three different variants of the TMD are shown in the table below:

  On the CBU-87/B, the SUU-65 dispenser is loaded with 214 BLU-97/B Combined Effects Munitions (CEMs), and is planned to replace almost every type of CBU. About the size and shape of a beer can, each CEM is equipped with its own ballute, making each a tiny high-drag bomb. It is designed to have excellent weapons effects against armored vehicles and exposed infantry, as well as superb incendiary effects against targets like fuel and ammunition dumps. The BLU-97/B accomplishes this through the use of a unique triple-function pyrotechnic package. Its anti-armor capability comes from a shaped charge capable of penetrating the top armor of virtually any tank or armored vehicle in the world. Surrounding the shaped charge is a serrated steel case, which fragments into hundreds of 30-grain size (about 1/4 in./6mm.) fragments. Finally, at the rear of the CEM is a ring of zirconium. When fragmented and heated to incandescence by the explosive of the shaped charge, it ignites violently as soon as it hits the oxygen of air.

  Armed with the finest general purpose submunition in the world, the CBU-87/B functions by delivering its load more accurately than any other dispenser in the inventory. Also, the CBU-87/B can be dropped from as low as 400 feet/121.9 meters, and as high as 40,000 feet/12,192 meters. This means that in addition to making tactical aircraft more survivable in high-threat environments, the CBU-97/B can now be used from bombers like the B-52, B-1B, and B-2. Some 10,035 CBU-87/Bs were dropped during Desert Storm, and in time, it will become the primary CBU in the USAF inventory.

  The second TMD derivative to be fielded is the CBU-89/B, which is designed to replace the earlier CBU-78/B in the mine deployment role. Composed of an SUU-64/B TMD, it is loaded with seventy-two BLU-91/B anti-personnel mines, and twenty-four BLU-92/B Gator anti-tank mines. The BLU-92/B Gator is an anti-vehicle mine with a highly sophisticated fuzing system, including the deployment of wire "feelers" to detonate the warhead. Once activated, the Gator fires a self-forging projectile or "spoon" into the belly of the target vehicle at a speed of over Mach 3, destroying the target. There were 1,105 CBU-89/Bs used during Desert Storm with great success.

  A cutaway drawing of the CBU-87/B version of the Tactical Munitions Dispenser (TMD).

  Jack Ryan Enterprises, Ltd., by Laura Alpher

  The newest TMD variant to make it into the field is the CBU-97B, which is equipped with the new BLU-108/B anti-armor submunition. First fielded in 1992, each CBU-97/B is composed of an SUU-64/B TMD, loaded with ten of the BLU-108/Bs. Known as a "sensor fuzed weapon," the BLU-108/B looks like an oversized coffee can when it is ejected from the TMD. Once clear of the TMD, each BLU-108/B ejects four small devices called "skeets." The skeets, which look a lot like jumbo-sized hockey pucks, are flung spinning from the BLU-108/B in four different directions to maximize their coverage. Once armed, each skeet scans the ground with a sensitive infrared seeker, tuned to look for the heat signature of an internal combustion engine. Should the skeet sensor detect the heat of a vehicle below, it fires a self-forging projectile or "spoon" down into the engine compartment of the vehicle at a speed of roughly Mach 5! The projectile has so much energy, that it just punches through the vehicle, even if it is a tank, usually destroying whatever it hits.

  With the coming of the SUU-64/65 TMD, most of the tactical limitations of previous types of CBUs have been eliminated. There is also a program, called the Wind Corrected Munition (WCM), which is designed to add a small, cheap, strapdown INS guidance system to the back of the TMD, along with guidance fins. The idea is that the inertial system would detect any course deviations resulting from crosswinds and correct for the wind drift. Given the hyper-accurate weapons delivery systems on various U.S. aircraft, particularly bombers like the B-1B and B-2, this would make truly accurate high-altitude CBU drops a reality.

  Electro-Optical Bombs: The GBU-15/AGM-130 Series

  Airpower enthusiasts have long dreamed of a munition which would drop a bridge or destroy a building with only one round. This has been the promise of airpower for over seventy-five years, and it has taken a long time to even get close to that. Like the AAM, the first real successes in the area of precision-guided munitions came from Nazi Germany in World War II. In 1943, the Luftwaffe deployed a pair of guided bombs, the FRITZ-X and the HS-293, for use as standoff precision strike weapons. Though they were quite primitive, they terrorized Allied shipping, and even sank an Italian battleship, the Roma, as it was on its way to surrender to Allied forces. After World War II, such efforts took a backseat to nuclear weapons development. Then, with the coming of the Vietnam War, the Air Force was forced to realize that there were a number of international situations where nukes were just not appropriate. Thus, the USAF went into Vietnam completely unequipped for the war they would spend the next decade trying to win.

  Immediately, the air units involved in the war began to find that they had been the victims of an unanticipated paradigm shift. Where in the past the flattening of a town with a carpet of GP bombs was a politically acceptable option, in Vietnam, it was a war crime. The politics of appearance were taking over in the 1960s, with the result that politicians now wanted the "surgical" air strikes that airpower zealots had promised for decades. Unfortunately, such promises by the visionaries who had created airpower as a weapon had never anticipated flying into an integrated air defense system (IADS) of fighters, SAMs, and AAA guns all tied together with a computerized sensor network of radars and observation posts. No one had anticipated that crews of tactical aircraft would be trying to drop their loads of munitions while violently "jinking" and fighting for their lives against coordinated multiple threats such as American pilots and crews saw in the skies over North Vietnam. Worse than that was where some of those bombs fell after they were dropped. Collateral damage is a serious concern in any war, but even more so when the enemy is showing American newsmen the destruction wrought by errant bombs and contrasting it with the stories of "precision strikes" coming out of official channels in Washington, D.C.

  In an effort to overcome the political problems of collateral damage, as well as the tactical problems of fighting in an IADS environment to precisely deliver ordnance onto a target, the USN and USAF initiated a series of programs known as Precision Avionics Vectoring Equipment (PAVE), designed to provide aviators with weapons that could hit high-value targets with some sort of standoff and precision. One promising technology was television electro-optics (TV E/O). This means that the guidance electronics package looks at the TV camera picture and locks onto the contrast "edge" or line between a dark and light zone on the picture. Integrated circuits and microprocessors were years away, and the early history of what we now call electro-optically (E/O) guided bombs was riddled with problems as a result.

  The Air Force E/O guided bomb program, known as the Glide Bomb Unit (GBU)-8 (also known by its program nickname of HOBOS, which stands for Homing Bomb System), was designed to be what is called a "modular" bomb. This means that the guidance kit (the seeker and guidance fin sections) would be literally bolted onto a standard -80-series bomb, which would act as the warhead. This meant that the warhead could be tailored for any kind of target that was required, be it heavy demolition (where a 2,000 lb./909.1 kg. Mk 84 would be appropriate), or area suppression (where a cluster bomb dispenser would be best). The GBU-8 was designed and built by Rockwell International in Columbus. Unfortunately, the USAF HOBOS had a poor combat career in Vietnam. There were a lot of single-point failures in various subsystems that made proper development of E/O bomb delivery tactics nearly impossible. But the worst of the problems revolved around the GBU-8 seeker itself. Because they had to actually see the target, the E/O bombs of the period could not be used in times of darkness or reduced visibility. In anything but "perfect" conditions, the WSOs had to take manual control of the HOBOS through the data links and try to fly the bombs onto the targets. Frequently, they did not have time to make the necessary corrections before bomb impact.

  By 1972, the shortcomings of the first-gen
eration HOBOS were well understood, and the Air Force initiated a program to develop an improved family of E/O guided bombs. Now known officially as the Modular Glide Bomb System, the new program was designed to overcome the problems that had plagued the early HOBOS. Following a design competition under the Pave Strike program, the USAF selected Rockwell International as the winner to build what would now be called the GBU-15. The major improvements that the GBU-15 was designed to have over the earlier GBU-8 included:

  • A longer standoff range to allow the launch aircraft to stay out of the range of SAMs and AAA guns.

  • More maneuverability and cross-range performance, to provide greater tactical flexibility, and to improve endgame accuracy during approach to the target.

  • An improved data link system, to allow greater control of the weapon during the terminal phase, the approach to the target.

  • A greatly improved seeker system, with greater resolution and target discrimination capabilities.

  • Options for improved seekers, including an infrared imaging (IIR) variant.

  With these ideas in mind, the Rockwell International engineers got to work. Though they started fresh with the new design, Rockwell kept most of the good things that the GBU-8 had offered, starting with a standard Mk 84 2,000 lb./909.1 kg. bomb body as the warhead. This time, though, with the emerging miracle of integrated circuitry and microprocessors, Rockwell was able to do a much better job. Rockwell also added Hughes Missile Systems to the GBU-15 team; they produced the TV seeker from technology based on their highly successful AGM-65 Maverick air-to-ground missile. As an added bonus, a version of the seeker based on technology from the Imaging Infrared (IIR) version of the Maverick was designed and eventually fielded.

  The basic GBU-15 is composed of a guidance/fin section, a bomb warhead, and a cruciform wing group (with steering fins) at the rear of the weapon. The following table shows the details of the various GBU-15 variants:

  The initial E/O version was known as the GBU-15(V)-1. Originally operational in 1977 with the Israeli Air Force (the USAF spent five more years testing and developing it), it is currently cleared for use on the F-111F and the F-15E Strike Eagle. It was followed by the IIR version, designated GBU-15(V)- 2, and is favored by crews and planners. Some seventy of the GBU-15(V)-2s were expended in the Persian Gulf during Desert Storm in 1991. Like the earlier HOBOS, it is equipped with a two-way data link, with the instructions and seeker video data being fed through a pod, designated AN/AXQ-14. This allows the WSO of the launching aircraft, or another controlling aircraft, to actually fly the bomb onto a target with truly stunning precision. In addition, the data link system allows the seeker video to be recorded; this assists in bomb damage assessment (BDA), as well as providing CNN with exciting videos!

  All the basic GBU-15s can be launched from a maximum range of 8 miles/14.6 km. at low altitude, and up to 20 miles/36.6 km. at higher altitudes. The key to this relatively long range is the lift capabilities of the cruciform wings at the front and rear of the GBU-15; these make the bomb an unpowered glider, with much greater maneuverability than previous HOBOS.

  Following Desert Storm, several new variants, called the GBU-151 series, came into service with the Air Force. But at an FY-1991 cost of $227,000 per copy, a GBU-15 is anything but cheap, and further development is unlikely. There is, however, one GBU-151 variant which is rapidly gaining momentum, the Air-to-Ground Missile (AGM) -130. The AGM-130 is basically a GBU-151 with a small rocket motor strapped to its belly. This has the effect of extending the AGM-130's range to 16 nm./30 km. at low altitudes, and up to 40 nm./45.7 km. at higher release altitudes. It's an impressive set of capabilities for one family of weapons, though it places a great burden of responsibility on its operators. WSOs assigned to operate the GBU-15/AGM-130-series weapons have to be carefully trained, and have a delicate touch, to get the most out of this most accurate of PGMs.

  Laser-Guided Bombs: The Paveway Series

  Once there were two bridges that were the stuff of nightmares to U.S. pilots who flew over North Vietnam. The Paul Doumer Bridge over the Red River in Hanoi and the Dragon's Jaw Bridge (Ham Rung in Vietnamese) near Thanh Hoa were the toughest targets in a war full of tough targets. Prior to 1972, despite the efforts of thousands of U.S. Air Force, Navy, and Marine strike sorties, millions of pounds of bombs, and dozens of lost airplanes and killed and/or imprisoned aircrews, the Paul Doumer was only dropped for a few weeks at a time. Then it would quickly be repaired, to carry rail traffic south, laden with supplies for the ground war in South Vietnam. Even worse, despite every effort that the Department of Defense could devise in the 1960s, the Thanh Hoa bridge was never dropped.

  Then, in just four days of May 1972, both targets went down for good, the most visible sign of a new weapons technology which saw its first use in 1967—the laser-guided bomb (LGB). On May 10th, 1972, sixteen F-4Ds from the 8th Tactical Fighter Wing (TFW) at the RTAFB at Ubon, Thailand, roared down on the Paul Doumer Bridge. Twelve of them were each armed with a pair of the new 2,000 lb./909.1 kg. LGBs. When the smoke and spray from the exploding bombs subsided, the bridge was heavily damaged and closed to all traffic. Amazingly, not one of the strike aircraft was damaged.

  Then, the next day, four more 8th TFW F-4Ds again attacked the Doumer Bridge with LGBs, this time dropping several spans. After several more applications of LGBs, the bridge would not be rebuilt until after the cease-fire in 1973. As an added bonus, the control bunker for the entire North Vietnamese air defense system at Gia Lam airfield was destroyed by four more LGB-ARMED F-4Ds from Ubon.

  The crowning achievement came two days later when the laser bombers of the 8th TFW went after the big one: the Dragon's Jaw. It took everything the ordnance shop and contractor techreps at Ubon could put together, including some specially built 3,000 lb./1,363 kg. LGBs; but when the smoke and limestone dust cleared, one whole end of the bridge had been lifted off of its abutment and heaved into the river.

  The weapons that did this amazing job were certainly not the most advanced or sophisticated ever deployed by the U.S. to Southeast Asia. On the contrary, first-generation LGBs were extremely simple in concept and execution, yet they have been the most successful type of PGM in history. Like the ubiquitous AIM-9 Sidewinder, a simple concept behind the LGB paid massive dividends when it got to war.

  If you are over forty, you probably remember when the magic of the laser beam was first touted by its inventors at Bell Labs. Laser stands for Light Amplification by Stimulated Emission of Radiation. What it means is that a coherent (composed of only one primary wavelength) beam of light with a very high amplitude (bright in the extreme) can be produced and manipulated. The first lasers relied upon solid materials like synthetic ruby to provide a medium to produce the laser light. Today, most lasers are based on gases like carbon dioxide (CO) or argon (AR). At the time of their introduction, lasers promised to become the "death beams" envisioned by science fiction authors like Jules Verne and H. G. Wells. But the truth was somewhat more modest, for the lasers of the 1960s had nothing like the power required to burn through the solid metal of a rocket or aircraft at tactical engagement ranges.

  Then in 1965, a simple idea for using the laser in a weapons system came to a small engineering team at Texas Instruments (TI). Weldon Word, the brilliant engineer who led the team, decided that instead of using the laser as a weapon, he would use the laser as a way to guide a weapon. Laser light, because it is coherent and tends to stay in a tight beam, has the ability to mark a very small target from a long distance. This means that a seeker could be devised that would "see" only a specific (coherent) frequency of laser light and guide onto it, much as the AIM-9M seeker looks for specific "colors" of light to home in on. It's like shining a flashlight in a completely dark room. If you are human, all you can see is the target illuminated by the flashlight.

  Simple as this sounds, it posed daunting technical and financial problems for Weldon Word and his TI team. As a starter, there was not much money to develop this
new strike technology. In the mid-1960s, DoD was offering $100,000 for ideas that could be put to winning use in Vietnam. But only $100,000 until the ideas had been tested and proven. For Word and his team, this meant the entire system — the seeker/guidance package, the laser "flashlight" (designator), and the warhead — had to be made for that $100,000, and not one penny more. Even in 1965, this would buy only a few thousand man-hours of TI engineering and technical talent, and a small amount of technical hardware for testing the concept. With only a short time available for development, the team made some important decisions. One of the first was that the warhead sections of the new guided bombs, now called Paveway, would be composed of normal 80-series LDGP bombs. The seeker and guidance sections would literally be "screwed" onto the LDGP bombs, providing a solid airframe for the whole package. This meant that the warheads, fuses, and assorted other equipment could be supplied, at no cost to TI, as government-furnished equipment (GFE). Then, rather than building the laser designator from scratch, they adapted a design from a scientist in Alabama. Finally, the team obtained their parts for the laser seeker from a West German salvage firm. Wind-tunnel testing of the proposed bomb package was found to be too expensive, so Weldon Word had his team test the bomb shapes with subscale models in a swimming pool.

  In spite of the "low ball" approach to the problem, the result was successful beyond the wildest dreams of anyone at TI or in the Air Force, even though the first Paveway laser designator (called Paveway I) was about the size of an old sheet-film camera, was bolted to the canopy rails of an F-4 Phantom, and was manually aimed through a telescopic lens by the backseater. Once this was done, then another aircraft had to fly over the target and drop the bomb. As might be imagined, this made the designating aircraft highly vulnerable to AAA guns and SAMs. Nevertheless, the results of the Vietnam combat tests held in 1967 were good enough for the Air Force to order the Paveway guidance kits into limited production. Eventually, the "limited" production wound up totaling over 25,000 units (each virtually hand-built) that were dropped during the Vietnam War. And amazingly, some seventeen thousand hits were scored, for an overall combat success record of some 68 %.