This article appeared in the July 1996 issue of Code One Magazine.

"The missile comes off with a lot of punch. It actually rocks the airplane," explains Lt. Tim Sundvall of his first live firing of an AGM-88 High-speed Antiradiation Missile. The HARM took off from the rail of his F-16 the day before and hit a radar target on the desert floor of the Utah Test and Training Range near Hill AFB. Sundvall, an F-16 pilot with the 14th Fighter Squadron of Misawa Air Base in Japan, launched one of many precision-guided munitions fired and dropped as part of an evaluation program for air-to-ground weapons. The program is known as Air-to-Ground WSEP or Combat Hammer.

Only a handful of F-16 pilots can describe a HARM shot from actual experience. The missile is limited to newer Block 50/52 F-16 aircraft and is very expensive. Furthermore, only a very few ranges can support HARM shots. Combat Hammer is the only opportunity, outside of combat that is, for operational F-16 pilots to fire a HARM. Interestingly, though, this first-hand description comes from a pilot with less than 500 hours in the fighter. Sundvall has been his squadron's low-hour F-16 pilot since arriving in Misawa over a year ago for his first operational assignment.

Still, Sundvall has quite a bit of experience with the HARM and the HARM targeting system. "Almost as much as anyone else in the squadron," he explains. "But we normally practice this mission without a missile." In other words, when Sundvall hits the pickle button, he has to watch the tape later at the squadron to see if he met all the right parameters. "Here, I got to see the missile come off the rail," he says. "That experience is a real confidence builder. As advertised, the targeting system does work on the F-16."

The HARM targeting system, or HTS, consists of a sensitive receiver that detects, classifies, and ranges ground radar threats. It is carried in a small pod on the right chin station of Block 50/52 F-16s. HTS passes targeting information to cockpit displays and to the missile.

It can also pass targeting information to non-HTS-equipped F-16s via internal data modems, a feature that was validated in separate tests during Combat Hammer.

Twelve pilots from Misawa fired HARMs during the one-week Combat Hammer exercise in April. The exercise also included Block 40 F-16s from Hill's own 34th Fighter Squadron (which dropped GBU-10 and GBU-24 laser-guided bombs), F-15Es from Lakenheath Air Base in England (which dropped GBU-10s and GBU-15s), and F-117s from Holloman AFB in New Mexico (which dropped GBU-10s and GBU-27s).

Combat Hammer exercises take place throughout the year. The schedule includes one concentrated two-week period at the Utah range and three or four evaluations at Eglin AFB's test range near the Florida panhandle. Other exercises this year had A-10s, F-15Es, and F-16s firing AGM-65 Maverick missiles; F-15Es firing AGM-130 rocket-powered glide bombs; and B-52s firing AGM-142 standoff missiles. This latter air-to-ground missile, also called Have Nap, has a fifty-plus-mile range and a 2,000-pound warhead. (Only the Maverick carries a functioning warhead in these evaluations.)

"I would like to come out to the Utah Test and Training Range more than once a year," says Lt. Col. George Clark, the commander of Eglin's 86th Fighter Weapons Squadron.

The 86th conducts Combat Hammer, ultimately for Air Combat Command. "Utah's biggest advantage is its large shoot cone," Clark says about the airspace and directional requirements that must be met on the range before a weapon can be released. "This range is a jewel. The Utah Test and Training Range is a big chunk of uninhabited DOD land. Here we can shoot HARMs, drop Paveway IIs, and fire Mavericks from a variety of altitudes. We can also perform multiship attacks. The range at Eglin, though, is suited for high-humidity and green terrain testing and training."

About half of the aircrews participating in Combat Hammer are like Sundvall: They have never fired or dropped live versions of these weapons before. "One of the objectives of air-to-ground WSEP is to give the first timers experience shooting live weapons," says Maj. Kelly Ranger, Combat Hammer's program manager for Air Combat Command. "We try to invite as many first timers as we can. Providing this initial experience is a secondary goal of WSEP. But it does relate to a more fundamental goal--to produce realistic operational numbers to ACC planners. Evaluating only the most experienced air crews would distort the data derived from this evaluation program."

And this data relates to the primary mission of Combat Hammer--to verify the combat capability of precision-guided weapon systems. "ACC is interested in anything this program can reveal about the ability of a weapon system to do its job," Ranger notes.

Weapon performance at both Air-to-Ground WSEP and at Air-to-Air WSEP, called Combat Archer, is tracked statistically by the Air Force. "Both WSEPs fall into a class of tests called follow-on test and evaluation," Ranger says. "In fact, most of this FOT&E in the combat Air Force today is being done at WSEP. Our statisticians look at each phase of the mission--from building up the weapons, to loading on the plane, to flying to the target area, to launching the weapon, to fuzing, to hitting the right target, to assessing the resulting damage." The mathematical product of the probability of success calculated for each phase determines the overall probability of success, or Ps , for a particular weapon.

"After every WSEP," Ranger continues, "we categorize this performance in a final report, which is forwarded to the field. We look at how a weapon's Ps changes over time. The information feeds into a document that aircrews eventually see, the Joint Munitions Effectiveness Manual. This manual gives them the statistical reliability of a weapon and the types of targets that weapon works best against. The information is also fed into models used to determine force structure."

"Another major statistic is hit rate," adds Lt. Col. Clark. "Hit rate is the measure of success given a release. It accounts for the time an aircrew hits a pickle button until the weapon hits the target.

"But the success of a weapon depends on much more than the weapon itself. It depends on the guys delivering it, the guys putting it on the airplane, and those building the weapon," explains Clark. "We have the units come in a few days ahead of time so we can evaluate their munitions build crews, testers, and loaders. We make sure they're using the latest equipment and technical orders. Our calculations of Ps , though, start on day one with a jet ready and the crew stepping."

ACC mandates these statistics be maintained to an eighty percent confidence level, "meaning we are eighty percent confident that our statistics will equal real-world results," Clark says. "An eighty percent confidence level statistically translates into about forty data points or weapons. A highly successful weapon, though, requires fewer points. If the first twenty of twenty shots hit the target, for example, we don't need all forty data points. Over time, we can also reach a confidence level where we can refresh the hit rate by looking at fewer test points, fewer weapons. The probability of success we see here tends to approximate real-world results closely. Our results have compared very well, for example, with recent operations in Bosnia."

This statistical relationship between the real world and the test world accounts for the existence of Combat Hammer. The first air-to-ground WSEP came about in 1986 when Paveway II laser-guided bombs were not performing as expected. The weapon's performance in training and exercises was not replicating the near-perfect performance in testing. ACC, Tactical Air Command at the time, wanted better analysis. Air-to-ground WSEP was the result.

The first Combat Hammer involved three aircraft types (A-10, F-4, and F-111) and two air-to-ground weapons (AGM-65A/B Maverick missiles and GBU-12 laser-guided bombs) in eight aircraft-weapon combinations. The program now evaluates twenty-six aircraft-weapon combinations. The overall goal of the program is to evaluate any new aircraft-weapon combination within one year of operational fielding.

The combination of F-16 and the hefty 2,000-pound laser-guided GBU-24 is one such relatively new combination. "The F-16 community in general doesn't have a lot of experience dropping GBU-24," explains Maj. Lee Hall of the 34th Fighter Squadron at Hill AFB. "When I left the airplane three years ago for a staff assignment, there was very little laser-guided bomb activity in the F-16 community. In fact, I had never even heard of the GBU-24 until I came back to the F-16. Now the airplane is dropping GBU-10s, -12s, and -24s."

Hall and other members of the 34th FS dropped a total of twelve GBU-24s during the exercise in April. "We've had a big learning curve from last year when our sister squadron, the 421st, dropped these weapons for the first time in this exercise," Hall says. "We tried not to repeat their mistakes. Before the exercise, we practiced GBU-24 drops for about two weeks in simulated attacks on local buildings."

Those simulated attacks can't duplicate the physical sensation associated with releasing more than a ton of metal from a small fighter. "Having that big bomb drop off the airplane is a big jolt in itself," Hall explains. "To balance the load, we carry a 2,000-pound Mk-84 on the opposite wing. When the GBU drops, the airplane banks to the heavy side, the trim is way off, and the airplane rolls. That is an eye opener. We can't simulate these reactions."

In addition, the pilots get to see what the bomb does. "We get to see how the attacks we think will work actually work," continues Hall. "We can see how the complete system works and how our targeting and navigation pods work together to get the bomb on target." Hall's advice to future participants: "Don't come here and expect to drop GBU-24s on the first day and have everything work out. Have the tactics developed and all the numbers crunched before getting here. It's a big learning curve. We learned a lot over the last month."

"A lot of these pilots get a world of experience in a very short time here," adds Capt. Mark DeVane. "They go through the entire process of dropping the weapon for the first time here rather than experiencing it for the first time in combat."

DeVane is the 86th FWS project officer for the HARM portion of the exercise, his third term as a WSEP project officer. "The 86th FWS does all the coordination," DeVane explains. "We set up all the threats and weapons. We try to tailor the threats for what they see in theater. We want them to fly and fire these weapons like they train to."

DeVane and test range personnel monitor the missions in a control center at Hill. The center receives and records telescopic infrared video from tracking stations set up around the test range, aircraft location information from transmitter pods mounted on the aircraft, and telemetry data from the weapon itself. Both weapons and aircraft are tracked by radar. Large screens in the center display video images of the target area.

The flight scenarios present a dose of realism. Participants must deal with adversary aircraft and a number of simulated surface-to-air threats and antiaircraft artillery on their way to the target area. "We have shot HARMs for three years at Combat Hammer," DeVane explains, "and every year the missions become more realistic. The first year the radar targets were located close to each other and we had a smaller shoot cone. The second year we opened up the shoot cone, but the targets were still pretty close together. This year we had a large shoot cone and a variety of targets, for example SA-2 and SA-3 sites. The targets are also better dispersed. RC-135 Rivet Joint and EA-6B Prowler jammers are involved this year as well. We built an entire electronic countermeasure scenario."

"The HARM targets get better every year," adds Clark. "They are not bunched up. We would love to have a complex target with a 360-degree shoot cone. So if winds are adverse in one direction, we can come at a target from another direction. Such an option may not be realistic for war, but it would allow us to use wind as a variable in these evaluations."

Operational scenarios have also become more realistic and more challenging this year. "Units operated as two ships in the past," DeVane explains. "This year they are operating as four ships. Since the following four ship overlaps the previous group, we have up to eight airplanes out there at one time. We try to vary the shot parameters from simple to complicated as the week progresses. We have more off-axis HARM shots by mid-week."

Lt. Col. Clark has some long-range ideas for improving the realism of Combat Hammer. "Ultimately," he explains, "we would like to integrate this program into Red Flag exercises. With the proper instrumentation on the Nellis range, we could make WSEP a transparent part of the Red Flag training. They already have plenty of threats and emitters. And they have a realistic training set. But they don't have the end game instrumentation to assess weapon drops properly."

While this integration effort may be years off, WSEP is addressing new operational issues this year. For example, 1996 is the first year that Combat Hammer actively sought out high-time weapons for testing. "When these weapons were designed, no one envisioned that they would be used in so many patrol missions," Ranger explains. "Some weapons at Aviano, for example, have been carried captive from 100 to over 1,000 hours. This trend presents potential problems. We could see rivets coming loose, weathering problems, and cracks related to stress or temperature gradients. We want to test weapons that are representative of what we will encounter in the field. This year, WSEP is evaluating high-time air-to-air missiles and laser-guided bombs from southern Europe and southwest Asia. We will expand the program next year for HARMs and Mavericks."

Combat Hammer is also addressing slight inaccuracies in laser-based target designators. "A small percentage of our misses are caused by the laser not matching the line of sight as displayed to the pilot," explains Clark. "Some pods are not boresighted well. Pilots cannot perceive this inaccuracy from the aircraft because they cannot see their own laser spot. And they don't get an indication when the system is out of tolerance. In fact, we won't find the inaccuracy until the next time the pod is calibrated. We are looking at systems that allow pilots to check their own laser designators. Basically, the pilot aims the laser at a ground target from the air. Someone on the ground or the target itself then verifies the precision of the laser spot."

"We get a lot of satisfaction out of finding problems with these systems and fixing them before someone takes the weapon into combat," DeVane says. "We want to make sure the Air Force has the best equipment. We are becoming a focal point for techniques for these weapons, a repository of information for increasing the overall combat capability of the Air Force. We don't want people continually relearning these techniques."

"A lot of this technology is portrayed on television and in Tom Clancy novels as being foolproof," adds Ranger. "If it were foolproof, we wouldn't need a program like WSEP. The public can't see all the ways to mess up a shot. So many extraneous factors are involved: the weather, the pilot, the airplane, the fog of war, and all the mechanical steps."

"Right," confirms Clark. "Regardless of what people saw on CNN, not every bomb dropped in the Gulf War was a direct hit. That perception of accuracy may have had a useful psychological effect during the war, but it distorts the public's expectations for these weapons. These munitions are not pinpoint accurate 100 percent of the time. Our job is to provide the DOD and theater commanders with realistic expectations."

While commanders get data from Combat Hammer, aircrews benefit more directly from the experience of firing and dropping actual weapons. "Simulation is a great way to train and it is cost efficient," Ranger explains. "But the first time you drop a real weapon, you don't want to do it in the heat of battle. Here, we help pilots get over any jitters that may accompany that first time."

"The meat of this exercise for us is testing the GBU-24 and making sure that we can deliver the weapon," says Hall, who dropped his first GBU-24 the day before. "The organizers throw in some realism with threat emitters and adversary aircraft. The GBU-24, though, is not a high-threat type weapon. We would have to have air superiority and SAM suppressors out there. Still, I'd rather have the learning curve occur over the range rather than over North Korea or someplace like that."

What about those first-time jitters? "No jitters," answers Sundvall. "But it is always somewhat of a surprise when something as big as a HARM comes off your airplane for the first time. A lot of training and a thorough understanding of the weapon system keep those jitters away."

Combat Hammer at Hill AFB included Block 40 F-16s from Hill's own 34th Fighter Squadron (which dropped GBU-10 and GBU-24 laser-guided bombs), F-15Es from Lakenheath Air Base in England (which dropped GBU-10s and GBU-15s), and F-117s from Holloman AFB in New Mexico (which dropped GBU-10s and GBU-27s).