General Dynamics F-111 AARDVARK/PIGSeptember 11, 2013
Posted on October 24, 2013
By Ray Panko | firstname.lastname@example.org | Pearl Harbor Aviation Museum
Two-Seat Medium-Range Heavy Tactical Bomber
Royal Australian Air Force F-111Cs in Flight at Nellis Air Force Base. United States Air Force photograph 060214-F-6911G-135. http://en.wikipedia.org/wiki/File:Australian_F-111s.jpg
- Although designated a fighter, the F-111 was a medium-range heavy tactical bomber
- Nicknamed the Aardvark, a solitary night hunter with excellent senses that roots round in the dirt
- First operational swing-wing aircraft, first turbofan with an afterburner, and pioneer of terrain-following flight
- Extremely long range on internal fuel alone; usually bombed without tanker support
- Heavy bomb load
- Mach 1.2 speed while hugging the terrain; Mach 2.5 at high altitude
- Highly politicized and wasteful procurement process
- Initial disaster in Vietnam
- Later success in Vietnam, Tripoli, and Desert Storm
- Used by the Royal Australian Air Force until 2010
- Our aircraft flew for many years with the Royal Australian Air Force (R double A F)
- In Australia, the Aardvark became the “Pig” Also, the “Triple One”
Somewhere in North Vietnam, December, 1972, 0300 hours, weather poor. Ear-shattering bomb blasts. No warning alarms. No package of fighter/bombers, fighters, jamming aircraft, and anti-SAM Wild Weasels. Survivors reported the sound of a one aircraft flying at high speed. Sometime later, a lone F-111 returns to its air base. It had made the entire trip alone. It had not needed a package of aircraft to protect it. It had not even needed a tanker. It taxied to its revetment, an elegant, enormous, and brutally effective strike bomber.
Its American crew called the F-111 the Aardvark. It was a good name. Like the South African aardvark, the F-111 was a solitary night hunter. Like the aardvark, it rooted in the dirt, guided by excellent senses. And like the aardvark, it had very long range. For much the same reasons, Australians called it the Pig.
The General Dynamics F-111 was a remarkable airplane. It was the first production aircraft to use swept wings. It had the first after-burning turbofan, which gave it both the power to fly supersonically at ground level and the efficiency to fly to Europe without tankers. It electronics that allowed it to fly at night, in any weather, and still find and destroy its target. Its sophisticated radar system controlled the aircraft, flying the nap of the earth to avoid detection. It could also take off from and land in 3,000 foot runways with obstructions up to 50 feet high at the ends.
Unfortunately, this wonderful machine had a terrible childhood filled with bad publicity. It was born in one of the most political and inept procurement debacles ever. The papers called it McNamara’s folly. Costs rocketed out of control, and the Navy version ended in expensive failure. Postmortems of the debacle also revealed that the wing box was defectively weak and that the inlet and engine were badly matched. NASA had to step in to solve the inlet problem. Fixing the wing boxes and other structural faults cost $100 million. Although the F-1111 eventually became an excellent aircraft, its initial publicity gave it an enduring bad reputation.
That was sad because the Aardvark grew up to become an excellent aircraft. Toward the end of the war in Southeast Asia, revamped F-111As were devastating in Linebacker II and in later fighting. They flew 4,000 missions with only six losses. In general, the F-111 had perhaps the best safety record of any major fighter. In 1986, eighteen F-111Fs accompanied by four EF-111A Raven electronic warfare aircraft flew from England, bombed Khadafi in Lybia, and flew back home. This was the longest strike mission in history. In Desert Storm, the F-111F really shone. Its Pave Tack avionics allowed it to locate its targets in the dead of night, track them, designate them with lasers, and hit them with smart bombs. In addition, despite its early crashes, the F-111 had one of the safest operating records in history.
The other major user of F-111s was the Royal Australian Air Force. With the growing obsolescence of its Canberra bombers, the RAAF need a new way of projecting power over regional distances. It began using the F-111C in 1973, roughly a decade after the aircraft was due to arrive. It used them through 2010, the last operator to do so. In 2013, the RAAF very generously gave the Pearl Harbor Aviation Museum one of its F-111s.
One source of confusion about the F-111 is the “F” in its designation. It was not a fighter at all. It was a medium bomber. However, the Air Force stopped using the “A” attack designation in 1947. It reserved the “B” prefix for big SAC bombers. The F-105 Thunderchief had stretched the F designation to its limits, and the F-111 was far beyond anything fighter-like. Still, the Air Force stubbornly resisted the attack designation until the A-10 many years later.
A Bad Beginning
In 1961, the Air Force saw the need for a new fighter/bomber and interdictor to replace the F-105. They wanted something that could fly much farther, carry a much heavier bomb load, and do this while flying supersonically nap of the earth. This complex new aircraft would have a pilot and a weapons system operator (wizzo) to handle the heavy workload. They would sit back to back, like crews in the F-4 and other Air Force fighter/bombers. Its role would be comparable to the medium bombers of World War II.
At the same time, the Navy needed an interceptor that could destroy Soviet bombers at long distances, before the bombers could launch their cruise missiles. This interceptor would need longer range and a longer loiter time at high altitudes than the F-4 Phantom II. It would need bisonic dash speed for delivering its long-range missiles. It would have two crew members, but they would be seated side by side in order to reduce the length of the aircraft so that it could operate from carriers.
Secretary of Defense Robert McNamara, only three weeks in office, noticed that the two aircraft would be roughly the same size, would both have a crew of two, and would both require swing wings for takeoffs and landings. Over strenuous arguments from the Air Force and Navy, McNamara decided to combine the two programs into a single procurement despite their very different detailed requirements. He decided that the Tactical Fighter Experimental (TFX) program would produce two slightly different versions of the same aircraft—the F-111A for the Air Force and the F-111B for the Navy. After a design competition, the Review Board selected the Boeing entry. McNamara overrode the Review Process because the General Dynamics design would cost less because it would have higher commonality in parts. In McNamara’s defense of this decision, Boeing really proposed to build two rather different aircraft of very limited commonality.
The Air Force managed the TFX airframe development. Not coincidentally, the final General Dynamics design was much closer to the Air Force requirements than to the Navy’s needs, although its two seats were side-by-side instead of in tandem as the Air Force originally wanted for rearward visibility. The F-111A gave the Air Force most of what it wanted. The F-111B for the Navy, however, was a disaster. The underpowered and temperamental Pratt and Whitney F30 engine and the heavy weight of the F-111B made it completely unsuitable for carrier operation and fighting interceptions. When Vice Admiral Thomas “Tom” Connolly flew the F-111B, he found that the aircraft had a hard time breaking Mach 1 and that its bulk and unsatisfactory engines would make it highly dangerous to operate from carriers. In a congressional hearing afterward, Senator Stennis asked the Admiral if more engine power would solve the problem. Connolly famously said, “There isn’t enough thrust in Christendom to fix this plane.” In 1968, the Navy was finally allowed to stop development of the F-111B. It began a new procurement, which ultimately resulted in the F-14 Tomcat.
The Air Force version, the F-111A, did reach production status. However, as noted in the introduction, costs had bloomed because expensive retrofits were added and because designs had to change constantly because of the confused acquisition process. TFX would forever be known as an object lesson in how not to procure aircraft.
Although the development process was chaotic and too often fatal to pilots, the basic design of the aircraft was sound. It is easiest to see this by looking at its design requirements and how they were addressed. (We will ignore the Navy’s design requirements since because were never used in an operational aircraft.)
The F-111A was created for a particular mission. This was an 800-mile radius nuclear strike. This LO-LO-HI mission would have three phases. On the outbound flight, the aircraft would fly toward its target at high subsonic speed while using its terrain-following radar system to hug the ground. Then would come a low-level bombing run to the target at Mach 1.2. After dropping its bombs, the aircraft would return to base at high level to stretch its fuel. These were extremely demanding requirements.
Of course, the F-111 never had to fly a nuclear mission in war. However, its requirements also made it a deadly aircraft for dropping conventional and smart bombs. A common training mission was to drop 8,000 pounds of bombs against a target 1,500 miles away, flying low level for 300 miles—without refueling.
The early 1960s was the era of bisonic flight, and the requirements put the F-111 fit squarely in this speed realm. The aircraft faced a requirement to operate at Mach 2.5 in high-level flight and Mach 1.2 in nap of the earth flight.
At the same time, the F-111 was required to have STOL capabilities. The F-105 needed enormously long takeoff runs of 6,000 feet. This greatly limited where it could be based. In addition, putting a handful of air bases out of operation would put the Thunderchief out of operation. The TFX aircraft would be required to take off and land in 3,000 feet, with 50-foot obstacles at each end. It would accomplish landings without a chute or engine thrust reversers. These runways, furthermore, might not be perfectly paved.
Figure 1: F-111F Takeoff
Source: United States Air Force Photo 060901-F-1234S-027
Range and Bomb Loads
In addition, the requirements called for unprecedented range and big bomb loads. For ferry flights, the aircraft could also be able to deploy from the continental United States to Europe without the in-flight refueling. The bird would also need to fly long strike missions with massive bomb loads of up to 30,000 pounds. To put things in perspective, the F-111 had twice the range of an F-4 Phantom II and could carry two and a half times the weapons load.
The requirements also stretched avionics technology to its limits. The F-111 would have to be able to fly nap of the earth. Its radar system would have to be able to keep it as low as 200 hundred feet above the ground in constantly changing terrain. It would do this automatically, without pilot intervention. The aircraft would also need advanced avionics to locate and bomb its targets at night and in bad weather. This requirement became even more important when smart bombs were developed later.
The requirements left the F-111 almost completely lacking in air-to-air capability. A 20 mm revolving gun pod that could be put in the internal bomb bay, but this was rarely done. Typically, the only air-to-air protection was two Sidewinder heat-seeker missiles.
Figure 3: F-111 with Sidewinder Missile
National Museum of the Air Force, USAF Photograph 071107-F-1234S-002.
The exacting requirements for the F-111 required a highly innovative design. They also required a very large aircraft. As shown in the specifications below, an F-111C with Pave Tack electronics had an empty weight of 54,000 pounds (23,300 kg) and a maximum gross weight of 114,300 pounds (52,000 kg). To help put this in perspective, the internal fuel alone weighs more than a combat-loaded F-16.
The requirements for supersonic speeds and STOL were incompatible in terms of wing design. The F-105, which the TFX’s requirements were to replace, illustrated this problem. To get bisonic speed, the F-105 used wings that could almost be called vestigial. They reduced drag to allow very high speed. However, small wings meant that there was little lift for takeoff and landing, so runs were legendary and takeoff and landing speeds were “exhilarating.” The F-105 required 6,000-foot runways, which were rare. This restricted possible basing and meant that it was often far from the troops it needed to protect. Also, taking out a handful of very large bases in a region would rule out the use of F-105s. STOL, in contrast, required very large wings. Glider wings would be ideal.
Figure 4: F-105 Thunderchief, Illustrating Narrow Wings
United States Air Force Photograph 060928-F-1234S-017.
It was apparent to everyone that there was only one way to get bisonic speed and STOL operation. This was to use variable geometry wings. Called swing wings, they stuck almost straight out from the fuselage for takeoffs and landings and swung far back to present minimum resistance during high speed flight. This addressed the requirements, but swing wings would also be complex and expensive.
The idea of variable geometry wings was not new. However, early attempts had both wings pivot from the middle of the fuselage. This did not work well because swinging the wing back and forth produced major changes in the center of gravity and the center of pressure. The Bell X-5 first faced this problem. Its wings pivoted out from a point in the center of the fuselage. This pivot point was mounted on a 27-inch rail. When the wings swung back, the pivot point was moved forward on the rail. When the wings swung forward, the pivot point was moved back on the rail. This worked, but the arrangement was too complex and heavy to be useful in future designs.
Figure 5: Bell X-5 Swing-Wing Experimental Aircraft
Source: NASA Photograph. http://en.wikipedia.org/wiki/File:Bell-X5-Multiple.jpg.
NASA conducted a large research program on swing-wing aircraft design. One design alternative that NASA developed was used the F-111 as well as in later aircraft, such as the F-14. Instead of placing the pivot point for the wings in the center of the fuselage, each wing was give its own pivot point, and the pivot point was placed several feet outboard of the fuselage. The pivot points were covered with an aerodynamic fairing and became part of the wing. This arrangement effectively divided each wing into two parts—a nonmoving wing glove section covering the wing pivot mechanism and a swinging section. As the swinging section swept back at higher speeds, it would lose aerodynamic effect. However, the wing glove section would increase its aerodynamic effect as speed increased. This lessened the shift in the center of pressure.
Figure 6: Arrangement of Wing Pivot Points in an F-111
Source: NASA, November 16, 2004. http://en.wikipedia.org/wiki/File:F-111_3-view.svg
The F-111 had another innovation. General Dynamics gave the aircraft large horizontal stabilizers that were gradually blanked as the wing swung back. This had the benefit of keeping the center of pressure even more stationary.
For takeoff, the wings had a sweep of 16 percent, and the aft placement of the pivot points of the wings made the aircraft look like a migrating goose. For supersonic dash, the pilot swept the wing to its maximum 72.5 percent sweep. At high subsonic speeds, the pilot used a sweep of approximately 10 percent of the aircraft’s speed in knots. The pilot controlled the swing wing using a hand grip on the left side of the cockpit. There was nothing like the automatic operation of the later F-14. Although manual adjustments kept the pilot busy, the pilot did not have to cope with the rapid sweep changes that would be needed in air combat maneuvering.
The F-111 was the first production aircraft with variable geometry wings. However, swing wings became very popular afterward, appearing on the F-14, the B-1B, the Tornado, and at least five different Soviet aircraft. However, it also brought complexity and cost. Advances in wing design eventually produced fixed wings that could give both adequate takeoff and landing performance and good supersonic performance.
To survive in the new world of high-reaching surface-to-air missiles, the F-111 would need to penetrate at ground level. Flying over terrain at low level would place a terrific load on pilots, and a single mental lapse would be fatal. To make nap-of-the-earth flight feasible, the F-111 had terrain-following radar. The radar system did not just map the terrain. It actually took control of the aircraft. The plane could fly under radar control as low as 200 feet above the terrain. Pilots could shift their course left and right, but the radar system controlled altitude without intervention. System breakdowns were handled by a simple expedient. The aircraft was instantly put into a climb to get it away from the ground until the pilot could take over.
The Vark’s swept-back wings made it relatively insensitive to low-level turbulence. It was called the Cadillac of low-flying aircraft. However, flying the Vark at low level could be disconcerting. The look-ahead radar only looked four degrees to each side, so crewmembers often found themselves flying below trees, towers, and gully embankments to their left and right.
Blind Navigation and Bombing
In the early years of the war in Southeast Asia, bombers had to wait on the ground if the weather turned bad, and night attacks were dangerous and ineffective. The Navy’s A-6 showed that radar-based blind navigation and bombing were possible. Avionics in the F-111 gave the Air Force this capability and did so with supersonic dash during the final attack.
Eventually, the F-111F received the even better AN/AVQ-26 Pave Tack electronics developed by Ford Aerospace. This 1,290 pound unit came in a pod that was mounted in the internal weapons bay and that rotated into position. It has a powerful forward-looking infrared (FLIR) search mechanism that pointed forward initially. After a target was located, the WSO designated it on his or her screen. The pod would then track the target automatically as the aircraft twisted and turned. The pod has a laser designator for laser-guided smart bombs. It could also control infrared and electro-optical guided bombs. As discussed later, F-111Fs used Pave Tack heavily in Desert Storm.
Figure 7: F-111F with Pave Tack Bombing Pod in Belly and Four 500 Pound Paveway II Smart Bombs
Source: United States Air Force Photograph in Triplet, 2002.
Afterburning Turboshaft Engine
Long range would require the efficiency of a turbofan engine. In a standard turbojet, hot exhaust gas pushing out the rear of the engine gives thrust. Some of the thrust is captured by the turbine in the rear of the engine. This turbine drives a compressor in the front, which compresses the air before it enters the combustion chamber.
In a turbofan engine, the compressor also drives a fan at the front of the inlet. The fan pushes cold air back, adding thrust beyond the thrust generated by the hot exhaust. Although driving the fan steals a little thrust from the jet exhaust, the thrust the fan generates more than compensates for the small loss. As a consequence, turbofans are very efficient for the amount of fuel the jet burns.
Figure 8: Low Bypass Ratio Turbofan
Turbofan engines were not revolutionary by this time, but supersonic speed would require adding an afterburner. It was not at all clear how to add reheat to a turbofan engine. Pratt and Whitney proved this by producing the temperamental TF-30, which did not tolerate abrupt attitude or thrust changes at high speeds. The Vark was the first aircraft of fly with an afterburning turbofan engine.
The F-111’s bombing role did not generate the violent high-G maneuvers that led to frequent F-14 compressor stalls with the same engine. However, the F-111 ran into its own problem with the engine. This was the mating of the engine to the airframe’s air inlet. Although the Air Force managed the development of the airframe, the Navy managed the engine development program. The engine air inlets, which were designed by General Dynamics to Pratt and Whitney specifications, proved to be a very bad match for the engines in practice. NASA finally stepped in and created a stopgap inlet design that was retrofitted to the fleet. There were still problems above Mach 2.2 at high altitudes, but this was something the Air Force could accept. Later improved inlet designs brought the F-111F back to a full Mach 2.5 performance and improved reliability in general.
Side-by-Side Seating with an Ejection Pod
At the insistence of the Navy, General Dynamics made the entire crew compartment an ejection pod. This pod was developed by McDonnell Douglas and was a marvel of engineering. The pod was ejected by a 40,000 pound thrust rocket. The pod included part of the wing fairing, and this stabilized the pod in initial flight. The pilot and wizzo rode the pod down to their landing, never having to risk flying in a seat through supersonic air. There were flotation bags to cushion the impact and for water landings. After egress, the pod could be as a survival shelter.
Figure 9: F-111 Cabin and Escape Pod
Source: United States Air Force Photograph. http://en.wikipedia.org/wiki/File:General_Dynamics_F-111A_cockpit_061003-F-1234S-015.jpg
Figure 10: Ejection Pod with Wing Fairing for Stability
Source: United States Air Force training film.
Although the escape pod was a good idea, it could not guarantee survival. The website www.ejection-history.orgkeeps lists of aircraft losses and ejection. Although the list is incomplete, it gives at least a rough feel for the safety or lack of safety of ejections from different aircraft. The website lists 132 F-111 losses, only some of which involved ejections. Details on crew survival were only provided in 32 cases. In 17 cases, both crew members were lost. In another, one died and the other was badly burned. In 13 cases, both crew members survived safely or with injuries. Ejecting from an F-111 was risky.
During the Aardvark’s life, General Dynamics developed a series of newer and better models.
The original model was the F-111A. As discussed earlier, it was rushed in production before its problems had even been identified, much less fixed. This resulted in numerous expensive refits. As just noted, the air intake had to be redesigned to prevent engine stalls. In addition, the expensive wing box proved to be too fragile and had to be replaced. These and other problems were fixable but not quickly or inexpensively. The Air Force built 159 F-111As before replacing it with the upgraded F-111E. The “A” model was the most widely built model in the series. Overall, 562 F-111s were built.
The F-111B was the Navy’s version. As noted earlier, it was never produced. The Navy required many changes from the Air Force design to allow the F-111B to land safely on carriers or even fit into elevators. The Navy version ended up eight feet shorter than the F-111A and had to go through a comprehensive weight reduction program that further reduced commonality. In addition the two services used different electronics suites. In the end, F-111A and the F-111B only had 30 percent commonality. The cost savings in producing both aircraft under these conditions would have been small. As noted earlier, the Navy was permitted to terminate the F-111B in 1968.
The F-111E came next in operational sequence. Essentially, this was an F-111A with an improved engine inlet. It took over the production line after the 160th F-111A. With the new wing inlet, the aircraft could now fly safely beyond Mach 2.2 to its maximum speed of Mach 2.5. General Dynamics produced 94 F-111Es. During Desert Storm, E models flew out of Incirlik Air Base in Turkey. Given their analog avionics, however, they could not carry precision guided munitions.
The F-111D added digital avionics and would grow into the definitive F-111F. It also got an engine power boost from 18,500 pounds to 19,600 pounds. Both of these developments took time, so the E model reached service well before the D model. Ninety Six F-111Ds were produced before production switched to the F-111F.
The F-111F was the final and definitive “fighter” model. An improved engine gave 25,000 pounds of thrust—35 percent more thrust than the A and E models. As we saw earlier, the F-111F mounted the Pave Tack system for target identification and designation using smart bombs. The F-111F conducted the raid on Khadafy’s Libya and was the terror of the night in Desert Storm. General Dynamics built 106 of these aircraft. The last F model came off the line in 1976. This was the end of F-111 production.
The F-111A was built for the Air Force’s Tactical Air Command. The Strategic Air Command was also interested in the new aircraft. SAC saw the airplane as potentially a good new medium-range low-level penetration bomber. The shooting down of Francis Gary Powers’ U-2 had increased concerns that SAMs had made high-flying B-52s vulnerable, and the future of the big bomb trucks was uncertain. SAC had the B-58 Hustler for medium-range attacks, but the Hustler was a pure nuclear bomber poorly suited for dropping conventional weapons. More pressingly, the B-58 was troublesome and reaching the end of its service life. A strategic bomber version of the F-111 would bring more mission flexibility.
In case of a nuclear war, its role would be to fly ahead of the B-52s, taking out antiaircraft sites and other command and control infrastructure. As Carlo Kopp put it colorfully, the FB-111A’s task would have been “carving out glow in the dark corridors through the PVO’s air defense SAM Belt.”
SAC purchased 76 FB-111As, which it named the Switchblade. These aircraft had their maximum wingspan increased from 63 feet to 70 feet and had other changes to give it longer range and a stronger body. At 114,000 lb, its maximum gross weight made it the heaviest F-111. However, its uprated engine of 25,000 pounds of thrust kept its speed very high. Its 11 percent extra capacity increased its ferry range to 3,500 nm, the longest for F-111s. In a nuclear bombing mission, the FB-111As’ range was still an impressive 1,200 nm. It could carry two nuclear bombs internally and another four on wing pylons.
Figure 11: FB-111As
Source: United States Air Force Photo DF-ST-84-09198. http://en.wikipedia.org/wiki/File:FB-111_Formation.jpg
However, concerns about the B-52 receded as the aircraft proved that it could fly low-level missions. Only 75 of the aircraft were built. In addition, the swing-wing B-1B bomber would offer everything the FB-111A could offer but with far greater range and bomb load. The Air Force retired its FB-111As, although it converted 34 back to fighter/bomber specs as the F-111G. In the United States, the converted aircraft were only used for training. However, as discussed later, the Australians used them to augment their small F-111 fleet.
There was one other important member of the family, the EF-111A. The “E” stood for electronic warfare. Although the EF-111A was officially the Raven, its pilots and electronic warfare operators (EWOs) called it the Spark Vark.
Grumman was the prime contractor for this aircraft, which was built by modifying 42 F-111As. In tactical operations, the Ravens accompanied bombing packages, disrupting enemy radar and communication. This required the addition of three key electronic warfare tools.
The most important was the Raytheon AN/ALQ-99E tactical jammer. This big device sat in the internal bomb bay. Its ten transmitters actually extended below the bomb bay, covered by a 16-foot long “canoe.” This powerful group of transmitters could blind radars from tens of miles away.
The second was the AN/ALQ-137 self-protection system to be used in case the aircraft itself was in danger of being intercepted.
The third was the terminal threat warning system, which warned the pilot and EWO that a missile had been launched at them.
Overall, the EF-111A had 6,000 pounds of additional electronics. In addition to the components mounted in the internal bay and the canoe, some were mounted in a distinctive pod on the top of the vertical stabilizer. This is the easiest way to recognize a Raven.
Figure 12: EF-111A Raven
USAF Photograph 020925-F-9999s-004.
In Desert Storm, 18 EF-111As flew 900 missions. Their jamming abilities gave strike packages complete safety from high-level anti-aircraft threats. By that time, the U.S was planning on depending on EA-6A electronic warfare aircraft. A dozen Ravens were retained until the new Navy craft were ready. The EF-111As were retired in 1998, the last of the F-111 variants to fly.
Ironically, the EF-111A, which normally flew without air-to-air weapons, is the only member of the F-111 “fighter” family to claim a kill. During Desert Storm, one of the Ravens was attacked by a Iraqi Mirage fighter. Although the F-111 was never thought of as an agile aircraft, the Raven outmaneuvered the Mirage, which crashed trying to follow its victim.
Vietnam 1968: Combat Lancer
As discussed earlier, the F-111A’s introduction in Vietnam in 1968 was an unmitigated disaster. The Air Force pushed the aircraft into production before its problems were even known. It then rushed six to Southeast Asia before its unit had achieved even initial operational capability (IOC). By 55 missions, three had crashed, and four crew members had died. The three aircraft had not been lost in combat. Their horizontal stabilizers were too weak and cracked. Adequate prior testing would have revealed this problem. The press and Congress were outraged. When another crashed soon afterward at Nellis Air Force Base, the Air Force grounded the fleet. The planes had to go back for strengthening, especially at the pivot joint and wing carry-through box. Modifications cost around five million dollars per aircraft.
Figure 13: F-111As During Operation Combat Lancer
United States Air Force Photo. http://en.wikipedia.org/wiki/File:F-111As_Combat_Lancer_1968.jpg.
The Air Force finally sent its greatly improved F-111As back to South East Asia in 1972. They arrived just before Operation Linebacker II. This time, the Aardvarks quickly proved their worth. They could fly at night and in weather that grounded other Air Force bombers. They had no need for tanker support or support from ECM aircraft. They constantly hit surprised North Vietnamese positions and exited safely. In 4,000 missions over the North, only eight F-111As were lost from all causes. This was a mission loss rate of only 0.2 percent. Although the B-52s got the publicity from Line Backer II, the F-111As were key to operation’s success.
Figure 14: F-111A in Linebacker II
Source: United States Air Force
The United States continued to station F-111As and other assets in Thailand after the end of the war in Vietnam. In 1974 and 1975, they executed strikes against Khmer Rouge troops in Cambodia. In 1975, the Khmer Rouge captured the American container ship SS Mayaguez. Unable to locate the ship, the Air Force sent F-111As to search the area with their radars. They were able to find it, and they led to the raid that achieved its release. Although this incident took place after the Vietnam peace agreement, the names of the Americans killed during the incident were placed on the Vietnam memorial wall.
Operation Eldorado Canyon, Libya 1986
In 1986, the United States bombed Libya in retaliation for a large number of terrorist attacks funded by Moammar Khadafy. Called Operation Eldorado Canyon, this attack used U.S. Navy carrier aircraft in the Mediterranean. The big hitters, however, were 18 F-111Fs with 2,000 pound laser guided bombs, accompanied by four EF-111A Raven electronic warfare aircraft. These Aardvarks and Ravens were based in England. France, Germany, Spain, and Italy would not permit the bombers to overfly their countries, so the F-111Fs had to fly out over the Atlantic and enter the Mediterranean at Gibraltar. This required a round trip of 6,400 miles—the longest in history for tactical aircraft. The flight took 13 hours and required 8 to 12 refuelings per aircraft.
Operationally, the attack was not highly successful. Only four of the F-111As were able to drop their bombs on their targets. Seven missed and six had technical problems or aborted to avoid breaking the rules of engagement. One was lost, probably from a SAM hit. However, Khadafy got the message. He pulled back from his support of terrorism. The experience also taught the Air Force some bitter lessons in using the F-111F that would pay enormous dividends a few years later.
The United States denied that they were specifically targeting Khadafy, but the press was able to ferret out extensive evidence that Khadafy was, in fact, the principle target. Less than three hours before the attack, intelligence agents had confirmed that Khadafy was in the Bedouin tent outside his conventional compound. Several of the F-111s hit the tent area and the compound. Of Khadafy’s wife and eight children, all were hospitalized, and one died of injuries. Khadafi was not seen for many days, but he eventually emerged, badly shaken. The attack would have been even more deadly, but four of the F-111s targeted against the compound had avionics failures that prevented them from dropping their 16 bombs.
Desert Storm, 1991
The F-111 truly came into its own in Operation Desert Storm in 1991. Although it dropped most of its weapons at high altitudes instead of “rooting around in the dirt” as usual, the F-111’s long endurance, ability to fly to distant targets quickly, and precision target identification and bomb guidance system at night made it devastatingly effective. In the brief Desert Storm air war, 84 Aardvarks (only some of which were F models with Pave Tack) flew over 4,000 sorties. Pilots discovered that they could blow the door of a bunker with a first bomb and then place the next bomb inside the bunker. Although they focused on high-value fixed targets, F-111F pilots quickly learned to everyone’s surprise that they could also hit moving tanks with their smart bombs. In fact, this “tank plinking” destroyed 1,500 armored vehicles during the brief air war. Tank plinking demonstrated the flexibility of the F-111 as an attack aircraft. Overall, the 66 F-111Fs sent to the war dropped about half of the 8,000 smart bombs dropped during the conflict.
Pigs Down Under
When the USAF was developing its specifications for the F-111, Australia also needed a new strike aircraft. Indonesia, which represented a major potential threat in the early 1960s, had Soviet Bombers that could strike Australia, but Australia’s existing Canberra bombers did not have the range to strike back. The F-111 would allow Australia them to take out aggressor air forces on the ground and then turn to other targets. The Royal Australian Air Force ordered 24 F-111Cs off the drawing board. These were based on the F-111A but were redesigned for the needs of the Royal Australian Air Force. One change was to give the Australian Aardvarks an anti-shipping role by allowing them to strike with AGM-84 Harpoon missiles. In addition, the Cs had the heavier landing gear and wider wings created for the F-111B and FB-111A.
Figure 16: RAAF F-111C “Pigs” at Amberley
Source: DFST8300042. http://en.wikipedia.org/wiki/File:F-111s_81.jpg
After prolonged development, General Dynamics finished the F-111Cs for Australia in 1968. However, the Royal Australian Air Force would not accept them until concerns about aircraft longevity had been worked out. The most important concern was the strength of the wing carry through box, which failed in a test. Finally, the wing carry through boxes were replaced at great cost. In 1973, Australia accepted its two dozen F-111C, which its crewmembers nicknamed the Pig. These aircraft were upgraded several times. In 1979, the RAAF modified four to carry reconnaissance pods.
Although two dozen aircraft would serve the needs of two full squadrons, this did not provide any spares. Inevitable attrition led to the purchase of four refurbished F-111As from the U.S. Air Force. These were upgraded these to the general F-111C specification. When the United States retired its FB-111As, it converted some to F-111Gs, as noted earlier. The RAAF was able to purchase fifteen F-111 Gs in 1983. This gave adequate replacement aircraft for several years. In the 1990s, the RAAF purchased ten Pave Tack target detection, tracking and designation pods.
Fortunately, Australian pigs never saw combat. However, in the East Timor crisis of 1999, Australia stationed its F-111 fleet in striking distance of East Timor. The Indonesians knew that the F-111s could devastate their ground forces if they took unacceptable action. This and the other threats posed by the Australian naval fleet kept the Indonesians in check.
In time, however, the high maintenance burden of Australia’s F-111 fleet led to the retiring of the fleet. The F-111Gs were retired in 2007, the F-111Cs in 2010. After 37 years of service, the RAAF held a moving farewell ceremony for its beloved Pigs.
Figure 17: Farewell Ceremony, December 2010
Source: Royal Australian Air Force Facebook Page.
Figure 18: Final Ceremony
Source: RAAF Facebook page.
In place of the long-range fighter/bomber, the RAAF has purchased 24 F/A-18F Super Hornets. It plans to upgrade to F-35s as these become available. Neither has the phenomenal range and loitering time of the Triple One, but both are modern superlative airplanes.
Figure 19: F/A-18F Super Hornet at Amberley
Source: RAAF Facebook page.
After decommissioning its F-111s, the RAAF faced the need to dispose of its aircraft in ways permitted by the SALT treaty. Eight had crashed while in service, and 23 were buried in in landfills. Six were retained at RAAF bases, and the others were made available to civilian museums. The final Triple One, F-111C A8-130, was delivered to Pearl Harbor Aviation Museum in September 2013. All but one were delivered by truck to their destinations.
Figure 20: Pig and Sheep
The last aircraft, A8-130, is one of the original two dozen F-111Cs purchased by Australia. This bird, with construction number D1-6, began its service on June 1, 1973. It left service on December 3, 2010. During its long career, many pilots flew this aircraft, including the Chief of the RAAF, Air Marshall Geoff Brown OA and Deputy Chief of the RAAF, Air Marshall Gavin “Leo” Davies. Shipping the aircraft to Hawaii presented a real challenge. The aircraft was finally divided into components and shipped to Hawaii by the RAAF in a C-130.
Figure 21: En Route to Hawaii
Early in its career, the aircraft flew in camouflage. The RAAF restored the aircraft to its camouflage paint job to commemorate its early history.
Figure 22: F-111C A8-130 in Early Camouflage
Source: RAAF Photo 000-144-094
During its long career, the A8-130 participated in many air shows. The following pictures of the A8-130 were taken by Jens Hameister. He has graciously given the museum permission to show these copyright pictures.
Source: Jens Hameister. Used with permission.
Source: Jens Hameister. Used with permission.
Source: Jens Hameister. Used with permission.
Doing a fuel dump and burn. Source: Jens Hameister. Used with permission.
Here is another picture of the aircraft, this time at the Pitch Black exercise in 2010. It shows the A8-130 from a high view as it taxies on the ground.
Source: RAAF Photograph 8540652_0027
|Wingspan swept (72 degrees sweep)||
|Wingspan extended (16 degrees sweep)||
|Weight (basic with Pave Tack)||
|Maximum takeoff weight||
|Pratt & Whitney TF-30-P-103 turbofan engines|
|Maximum speed at sea level||
|Maximum speed at altitude||
420 kt (483 mph)
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