The AIM-54A achieved its initial operational capability in 1974 with the introduction of the F-14A Tomcat. The Phoenix uses either an Aerojet Mk 60 or Rocketdyne Flexadyne Mk 47 long-burn-time solid-fuel rocket motor, semi-active radar midcourse guidance, active radar terminal guidance, and a impact or proximity fused 132 pound high explosive warhead. The missile is capable of Mach 5.0 at high altitudes and has a range in excess of 100 miles. At low altitudes, the AIM-54 is limited to Mach 3.8 by aerodynamic heating considerations.
After launch, the Phoenix can use three different types of guidance – autopilot, semi active radar homing, or fully-active radar homing. For long-range shots, the missile generally flies a pre-programmed route immediately after launch under autopilot control. At mid- course, the nose-mounted radar seeker takes over, operating in semi-active mode, homing in on radar waves reflected off the target from the Tomcat’s AN/AWG-9 or AN/APG-71 radar. Once it gets within about 14 miles of the target, the Phoenix’s own radar takes over for the final run in to the target, and the missile operates in fully-active radar homing mode.
At this time the missile is completely independent of its launching aircraft, and becomes ‘fire-and-forget’. Some reports have suggested the existence of a ‘flyout’ mode in which the missile can be launched at heavily- jammed targets upon which the F-14 radar is unable to achieve a lock. In such a mode, the missile flies most of the way to the target under autopilot control, switching over to its built-in seeker for the final approach.
Several performance modifications were incorporated into AiM-54As both during and after production. The Reject Image Device (RID) offered improved capabilities against low altitude targets over water, and was incorporated during production of later missiles. The Extended Active Gate (EAG) improved the missile’s resistance to certain ECM threats, and was also a production feature of later missiles. The High Altitude Performance (HAP) modification improved performance against very high-altitude and high-speed targets. This feature was added to late production missiles, and was also retrofitted to some earlier missiles. A modification to the warhead, designated Mk 11 Mod 3 EA, improved the warhead lethality against small targets, and was a retrofit item only.
The Phoenix missile is 13 feet long, 15 inches in diameter, has a 3 foot wing span, and weighs 1,008 pounds (AIM-54A) or 985 pounds (AIM-54C). There are two production versions of the Phoenix: the initial AIM-54A which was phased out of production in 1980 after 2,566 had been built; and the follow-on AIM-54C with improved ECCM capability and reliability. An AIM-54B version was to substitute sheet metal wings for the difficult to manufacture honeycomb ones of the AIM-54A, along with other detail improvements to ease production and maintenance. This version never reached production due to budgetary considerations and the subsequent introduction of the AIM-54C.
Development of the improved AIM-54C missile was undertaken in October 1976 with Hughes delivering the first engineering development models in August 1979. An increased emphasis was placed on the missile after the Iranian revolution to minimize the usefulness of any information about the AIM-54A that might have fallen into Soviet hands. Pilot production of 30 rounds for fleet evaluation began in early 1981 and the first production missile was delivered on 27th October 1981.
The AIM-54C featured a new DSU-28C proximity fuse, a new digital electronics unit, inertial navigation reference system, and a solid-state receiver-transmitter. The Navy had a stated requirement for 3,467 of the missiles, to be produced at a peak production rate of 60 per month at a total cost of $4.1 billion.
Quality control problems at Hughes Tucson plant caused the Navy to suspend acceptance of AIM-54Cs on 22nd July 1984, but these were subsequently resolved and deliveries resumed later that year.
The AIM-54C ECCM/Sealed missile provides two major improvements over the early AIM-54C: enhanced electronic counter-coun- termeasures (ECCM) capability and the elimination of the liquid cooling oil. The missile’s external appearance remains unchanged. This version of the Phoenix is also known as the AIM-54C+, and made its first flight on 14th August 1990. The F-14D is not equipped with the cooling oil system. The older missiles physically fit on the F-14D, but there are some flight restrictions In order to minimize the effects of aerodynamic heating since the aircraft cannot cool the missiles in flight.