The beginnings of the F-111 were in the TFX program, an ambitious early 1960s project to combine the U.S. Air Force requirement for a fighter-bomber with the U.S. Navy's need for a long-range carrier defense fighter to replace the F-4 Phantom II and the F-8 Crusader. The fighter design philosophy of the day concentrated on very high speed, raw power, and air-to-air missiles.

The USAF's Tactical Air Command (TAC) was largely concerned with the fighter-bomber and deep strike/interdiction roles, which in the early 1960s still focused on the use of nuclear weapons. The aircraft would be a follow-on to the F-105 Thunderchief, which was designed to deliver nuclear weapons low, fast and far. Air combat would be an afterthought until encountering MiGs over Vietnam in the mid 1960s. In June 1960 the USAF issued a specification for a long-range interdiction/strike aircraft able to penetrate Soviet air defenses at very low altitudes and very high speeds to deliver tactical nuclear weapons against crucial Soviet targets like airfields and supply depots. Included in the specification were a low-level speed of Mach 1.2, a high-altitude speed of Mach 2.5, a combat radius of 890 mi (1,430 km), good short-field performance, and a ferry range long enough to reach Europe without refuelling.

Meanwhile the US Navy had, since 1957, been searching for a long-range, high-endurance interceptor to defend its carrier groups against the new generation of Soviet jet bombers, which by then were being armed with huge anti-ship missiles with nuclear warheads. The Navy needed a Fleet Air Defense (FAD) aircraft with better loitering performance and load-carrying ability than the F-4 Phantom II, and one equipped with a powerful radar and a battery of long-range missiles to intercept both bombers and their missiles.

The Navy had studied, but rejected, a slow straight-winged missile carrier, the F6D Missileer. In December 1960 the Navy had been reconsidering variable geometry for the FAD requirement. The trend toward ever bigger, more powerful fighters posed a problem for the Navy: the current generation of naval fighters were already barely capable of landing on an aircraft carrier deck, and a still larger and faster fighter would pose even greater problems. An airframe optimized for high-speed — most obviously with a high-angle swept wing — is inefficient at cruising speeds, which reduces range, payload, and endurance, and leads to very high landing speeds. On the other hand, an airframe with a straight or modestly swept wing, while easier to handle and able to carry heavy loads over longer distances on a minimum of fuel, has lower ultimate performance. Variable geometry, which the Navy had tried and abandoned for the XF10F Jaguar in 1953, offered the possibility of combining both in a single airframe.


The F-111 was the first production variable-geometry aircraft. The earlier subsonic Navy XF10F Jaguar had been cancelled in 1953. It inspired a number of aircraft throughout the 1980s, and even fictional aircraft on the Thunderbirds, but swing wings are extinct in newer designs due to higher cost, and the extra weight imposed by the swing wing mechanism. Nevertheless, several other types have followed, including the Soviet Sukhoi Su-17 "Fitter" (1966), Mikoyan-Gurevich MiG-23 "Flogger" (1967), Tupolev Tu-22M "Backfire" (1969) and Tupolev Tu-160 "Blackjack" (1981), the US F-14 Tomcat naval fighter (1970) and B-1 Lancer bomber (1974), and the European Panavia Tornado (1974). The Sukhoi Su-24 "Fencer" (1970), which resembles the F-111, also has side-by-side seating.


Although conceived as a multi-role fighter, the F-111 became a long-range attack aircraft primarily armed with air-to-surface ordnance.

The F-111 has a small internal weapons bay under the fuselage for various weapons.

* Cannon: All tactical combat versions (that is, not the EF-111A or FB-111A/F-111G) could carry a single M61 Vulcan 20 mm cannon with a very large (2,084 round) ammunition tank, covered by an eyelid shutter when not in use. Although carried by some USAF aircraft, the cannon was never actually used in combat, and was removed by the early 1980s; provision for the cannon has also been deleted from Australian F-111Cs.
* Bombs: The bay can alternately hold two conventional bombs, usually the Mk 117 type of nominal 750 lb/340 kg weight, although weapons up to the Mk 118 (3,000 lb/1,400 kg) were cleared.
* Nuclear weapons: All F-111 models except the EF-111A and the Australian F-111C were equipped to carry various free-fall nuclear weapons: tactical models generally carried the B43, B57, or B61, the FB-111A those weapons or the B83. The FB-111A could also carry one or two AGM-69 SRAM nuclear missiles in its weapons bay.
* Sensor pod: The F-111C and F-111F were equipped to carry the AN/AVQ-26 Pave Tack targeting system on a rotating carriage that kept the pod protected within the weapons bay when not in use. Pave Tack is a FLIR and laser rangefinder/designator that allows the F-111 to designate and drop laser-guided bombs.
* Reconnaissance pallet: Australian RF-111Cs carry a package of reconnaissance sensors and cameras for tactical recce missions. It contains two video cameras, a Honeywell AN/AAD-5 infrared linescan (recorded on video or film), a Fairchild KA-56E low-altitude and KA-93A4 high-altitude panoramic cameras, and a pair of CAI KS-87C split vertical cameras. It can also record photographs of the attack radar's display.
* Missiles: The F-111B was intended to be capable of carrying two AIM-54 Phoenix air-to-air missiles in the bay. General Dynamics proposed an arrangement that would allow two AIM-9 Sidewinders to be carried on a trapeze mounting in the bay (at the expense of the M61 cannon), along with a single (usually nuclear) bomb. This was not adopted, with the USAF and RAAF opting for the cannon instead. The AIM-7 Sparrow or AIM-4 Falcon, standard on the F-4, was never fitted, though later F-111 models had radars equipped to guide the Sparrow.[citation needed]
* Other equipment: Auxiliary fuel tanks and baggage pods were sometimes carried.


The design of the F-111's fuselage prevents the carriage of external weapons under the fuselage (although there are two small stations, one on the weapon bay, the other on the rear fuselage between the engines, for ECM pods and/or datalink pods for guided weapons). All aircraft have provision for eight underwing pylons, four under each wing, with a capacity of 6,000 lb (2,700 kg) each. The inner pylons (3, 4, 5 and 6) pivot with the wing, but only one on each side can be loaded at maximum sweep. The outer pylons (1, 2, 7 and 8) are fixed, and can be loaded only if the wings are spread at less than 26°, causing drag at takeoff angle. The outermost pylons (1 and 8) have never been used operationally, and the second pair of fixed pylons (2 and 7) are fitted only rarely, for the carriage of fuel tanks. FB-111/F-111G models have provision to jettison their empty pylons in flight, reducing drag.

The limited number of fully swiveling pylons restricts the F-111's maximum practical weapons load, since the aircraft cannot use all pylons with the wings fully swept. By contrast, aircraft such as the F-14 and Tornado can carry their maximum bomb loads with fully swept wings.

Although all F-111s can carry laser-guided munitions, only those with Pave Tack (i.e., F-111F and Australian F-111C) are capable of self-designation. Others can drop laser-guided weapons only with the aid of another ground or air designator.

From the early 1980s onward, tactical F-111s were fitted with shoulder rails on the sides of the outboard swiveling pylon (designated stations 3A and 6A) for two AIM-9 Sidewinder air-to-air missiles for self-defense. The standard Sidewinder fit was the AIM-9P, rather than the more modern AIM-9L or AIM-9M, whose larger fins were not compatible with the shoulder rail. The RAAF has considered replacing the Sidewinder with ASRAAM.

FB-111As could carry the same conventional ordnance as their tactical brothers, but their wing pylons were more commonly used for either fuel tanks or strategic nuclear gravity bombs. Until the weapon was withdrawn in 1990, they could carry up to four AGM-69 SRAM nuclear missiles on the wing pylons, although two was the more normal fit.

Australian F-111Cs have been equipped to launch the AGM-84 Harpoon anti-ship missile, AGM-88 HARM anti-radiation missile, and the AGM-142 Popeye stand-off missile.

Operational history

The Strategic Air Command had FB-111s in service from 1969 through 1990.

The F-111 was in service with the USAF from 1967 through 1998. It entered active service with the Royal Australian Air Force in 1973 and is currently scheduled to remain with the RAAF until 2010. Concerns of the RAAF not having an aircraft to replace the F-111's role between retirement of the F-111 and the introduction of the F-35 Lightning II were quashed with the announcement by the Australian Department of Defence on 7 March 2007, that the RAAF would procure 24 F/A-18F Block II Super Hornets, with the first being delivered in 2010, and the last scheduled for delivery in 2011.