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F-111

The F-111 was a multipurpose tactical fighter bomber capable ofsupersonic speeds. The aircraft was one of the more controversialaircraft ever to fly, yet it achieved one of the safest operationalrecords of any aircraft in USAF history and became a highly effectiveall-weather interdiction aircraft. As a result of a poorlythought-out development specification, both the Navy and Air Force hadbecome committed, much against their will, to a civilian-inspired"Tactical Fighter Experimental" (TFX) program. This called fordeveloping a single aircraft - the F-111 - to fulfill a Navyfleet-defense interceptor requirement and an Air Force supersonicstrike aircraft requirement. In retrospect, this was impossible toachieve, especially since planners placed priority upon the Air Forcerequirement, and then tried to tailor this heavy landplane to theconstraints of carrier-based naval operations. The naval aircraft, theF-111B, was never placed in production. The Air Force aircraft, whichwas produced in a variety of models, including the F-111A, F-111D,F-111E, and F-111F, as well as an FB-111A strategic bomber version,had numerous problems, and only the F-111F actually fulfilled theoriginal TFX design specification. This was less the fault of GeneralDynamics than of the civilian planners in the Pentagon whose "costeffective" inclinations ironically produced the major aeronauticalfiasco of the 1960s-and a costly one at that.

The early F-111As had extremely bad engine problems, sufferingfrom compressor surge and stalls. NASA pilots and engineers wrung outthe airplane in an attempt to solve its problems, studying the engineinlet dynamics of the plane to determine the nature of inlet pressurefluctuations that led to compressor surge and stall. Eventually, as aresult of NASA, Air Force, and General Dynamics studies, the engineproblems were solved by a major inlet redesign.

The F-111 could operate from tree-top level to altitudes above60,000 feet (18,200 meters). The F-111 had variable-sweep wings thatallow the pilot to fly from slow approach speeds to supersonicvelocity at sea level and more than twice the speed of sound at higheraltitudes. Wings angle from 16 degrees (full forward) to 72.5 degrees(full aft). Full-forward wings gave the most surface area and maximumlift for short takeoff and landing. The F-111 needed no drag chute orreserve thrust to slow down after landing.

The two crew members sat side-by-side in an air-conditioned,pressurized cockpit module that served as an emergency escape vehicleand as a survival shelter on land or water. In emergencies, both crewmembers remained in the cockpit and an explosive cutting cordseparated the cockpit module from the aircraft. The module descendedby parachute. The ejected module included a small portion of the wingfairing to stabilize it during aircraft separation. Airbags cushionedimpact and help keep the module afloat in water. The module could bereleased at any speed or altitude, even under water. For underwaterescape, the airbags raised the module to the surface after it has beensevered from the plane.

The aircraft's wings and much of the fuselage behind the crewmodule contained fuel tanks. Using internal fuel only, the plane had arange of more than 2,500 nautical miles (4,000 kilometers). Externalfuel tanks could be carried on the pylons under the wings andjettisoned if necessary.

The F-111 could carry conventional as well as nuclear weapons. Itcould carry up to two bombs or additional fuel in the internal weaponsbay. External ordnance included combinations of bombs, missiles andfuel tanks. The loads nearest the fuselage on each side pivoted as thewings swept back, keeping ordnance parallel to the fuselage. Outerpylons did not move but could be jettisoned for high-speed flight.

The avionics systems included communications, navigation, terrainfollowing, target acquisition and attack, and suppression of enemy airdefense systems. A radar bombing system was used for precise deliveryof weapons on targets during night or bad weather.

The F-111's automatic terrain-following radar system flew the craftat a constant altitude following the Earth's contours. It allowed theaircraft to fly in valleys and over mountains, day or night,regardless of weather conditions. Should any of the system's circuitsfail, the aircraft automatically initiated a climb.

Variants

TheF-111A first flew in December 1964. The firstoperational aircraft was delivered in October 1967 to Nellis Air ForceBase, Nev. A models were used for tactical bombing in SoutheastAsia.

Developed for the U.S. Navy, theF-111B was canceled beforeits production.

F-111C's were produced for the Royal Australian Air Force.

TheF-111Dfeatured improved avionics with better navigation,air-to-air weapon delivery systems, and newer turbofan engines. TheF-111D's were flown by the 27th Fighter Wing, Cannon Air Force Base,N.M.

TheF-111E model had modified air intakes to improve theengine's performance at speeds above Mach 2.2. Most F-111Es servedwith the 20th Fighter Wing, Royal Air Force Station Upper Heyford,England, to support NATO. F-111E's were deployed to Incirlik Air Base,Turkey, and were used in Operation Desert Storm. In the early morningof Jan. 17, 1991, the F-111 went into combat again in the initialbombing raids of Operation Desert Storm. More than 100 F-111 aircraftof different versions joined the first strikes against Iraq both asbombers and radar jammers.

TheF-111F had improved turbofan engines that gave F-111F models35 percent more thrust than previous F-111A and E engines. Theavionics systems of the F model combine features of the F-111D andE. The last F model was delivered to the Air Force in November1976. The F models were modified to carry the Pave Tack system intheir weapons bays. This system provides an improved capability toacquire, track and designate ground targets at night for delivery oflaser, infrared and electro-optically guided weapons. The F-111F wasproven in combat over Libya in 1986 and again over Iraq in1991. Although F-111F's flew primarily at night during OperationDesert Storm, aircrews flew a particularly notable daytime missionusing the Guided Bomb Unit (GBU-15) to seal the oil pipeline manifoldsabotaged by Iraq, stemming the flow of oil into the Gulf.

As a result of the Air Force decision to retire the F-111 weaponsystem, the 27th Fighter Wing's 74 F-111E/F aircraft began retiring inlate 1995 and were replaced with 54 F-16C/D aircraft. All F-111s inthe Air Force inventory have been retired to the Aerospace Maintenanceand Regeneration Center at Davis-Monthan AFB, Ariz. The center,popularly know as the boneyard, was home to all the remaining F-111Eand F models by October 1996.

FB-111

Seventy-six were built as FB-111s and saw service with theStrategic Air Command until 1990 when they were converted to F-111Gsand assigned to Tactical Air Command. TheF-111G was assignedto the 27th Fighter Wing at Cannon Air Force Base and was used in atraining role only. The conversion made minor avionics updates andstrengthened the aircraft to allow its use in a more dynamic role as afighter aircraft.

EF-111A Raven

When converting the aircraft to its new electronic warfare role,the primary modification was the ALQ-99 jamming system, N/ALQ-137self-protection system, and an AN/ALR-62 terminal threat warningsystem. To accommodate the 6,000 pounds of new electronics, Grummanadded a narrow, 16-foot long canoe-shaped radome under the fuselageand a din-tip pod mounted on top of the vertical stabilizer.

Grumman’s EF-111A prototypes staged their first flights in1977. After two years of testing the Air Force gave the contractor thego-ahead to convert 42 F-111As into the EF-111 configuration. Themodifications cost approximately $25 million per aircraft, and thetotal cost of the program was $1.5 billion. The first productionEF-111 was delivered to the 388th Tactical Electronic Squadron atMountain Home AFB, Idaho, in November 1981 and the aircraft becamefully operational in 1983.

The Avionics Modernization Program (AMP) included the installationof 10 new subsystems including a doppler radar and internal navigationsystem. The modification, installed in all 42 EF-111s, was completedin 1994. Prompted by a series of crashes attributable to the failureof the F-111’s original analog flight control system, the installationof Digital Flight Control System begann in 1990 and was completed in1997.

The last squadron of EF-111s remaining in service, at Cannon AFB,NM, peformed the Suppression of Enemy Air Defense [SEAD] mission. DODdecided to retire the EF-111A jammer and replace it with a new AirForce system, the high speed anti-radiation missile (HARM) targetingsystem on the F-16C, and the existing Navy electronic warfareaircraft, the EA-6B. Recognizing that too few EA-6B aircraft may beavailable to meet both Air Force and Navy needs, DOD retained these 12EF-111s in the active inventory through 1998, when additional upgradedEA-6Bs became available.

F-111

EF-111 Raven

Sources and Resources

• FB-111 @ FAS nuke.guide

• F-111 Aardvark Carlo Kopp
• Gil's F-111 Page with lotsa pix
• A-10/F-111 SYSTEMS PROGRAM OFFICE

• EF-111As in SWA return home for the last time: Apr 10, 1998 (AFNS) - After 2,780 days and 32 continuous rotations in Southwest Asia enforcing theno-fly zone over Southern Iraq, EF-111A Ravens returned home for good. The EF-111 will retire from the Air Force inventory May 2.

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