SI VIS PACEM, PARA BELLUM: L'AIM-54 Phoenix era un missile aria-aria a lungo raggio

L'AIM-54 Phoenix era un missile aria-aria a lungo raggio, impiegato, fino ad un massimo di sei unità, dal Grumman F-14 Tomcat e progettato per difendere la flotta contro missili da crociera e da aeroplani come il MiG-25 Foxbat. 

L'USAF non ebbe armi paragonabili sino all'introduzione dell'AIM-120 AMRAAM, anche se un missile simile fu sviluppato per il Lockheed YF-12, prototipo della versione da intercettazione del Lockheed SR-71.

Alcuni esemplari del Phoenix sono ancora usati in Iran in una nuova variante, ma la loro operatività è dubbia dato che gli USA non riforniscono loro più i pezzi di ricambio necessari dalla rivoluzione del 1979.

Storia

Il Phoenix venne sviluppato a partire dalla fine degli anni sessanta per poter essere utilizzato nel Douglas F6D Missileer e negli F-111B, con la caratteristica fondamentale di avere un lungo raggio d'azione. La Hughes Aircraft Company creò dunque un missile, chiamato AAM-N-11, da associare ad un radar AN/AWG-9. Nel giugno 1963 si cambiò nome al progetto in AIM-54A e il primo prototipo, l'XAIM-54A, iniziò a volare nel 1965. La cancellazione dei progetti del Missile e dell'F-111 obbligarono a scegliere un nuovo vettore per il nuovo missile, e alla fine fu scelto l'F-14 Tomcat, che rimase l'unico caccia intercettore con integrata questo tipo di arma dal 1974.

Nell'agosto 1979 il volo del prototipo XAIM-54C soddisfece le esigenze dell'US Navy che ne autorizzò la produzione, deviandola dall'AIM-54A, nel 1982. Quest'ultima variante, l'AIM-54C, costituì circa la metà dei 5 000 Phoenix prodotti fino al 1990, anno in cui venne fermata la produzione.

Il Phoenix fu radiato il 30 settembre del 2004 principalmente a causa della crescente mancanza della minaccia che era stato chiamato a scongiurare, cioè l'attacco della flotta da missili o aerei nemici, seguito dal Tomcat l'8 febbraio del 2006 e rimpiazzati rispettivamente dagli AIM-120 AMRAAM (con portata inferiore) e dai McDonnell Douglas F/A-18 Hornet.

Caratteristiche tecniche e versioni

Il missile Phoenix (fenice) divenne l'unico missile a lungo raggio della Marina degli Stati Uniti ed era parte di un sistema d'arma con possibilità di acquisizione ed ingaggio di bersagli multipli: era possibile infatti agganciare fino a sei bersagli contemporaneamente in condizioni ognitempo e con sistemi di contromisure elettroniche (ECM) attivi grazie ad un'antenna radar che poteva illuminare il bersaglio senza assistenza del vettore lanciatore (l'F-14 appunto).

La struttura del missile era una versione in scala maggiore dell'AIM-47 Falcon con quattro alette incrociate; potevano essere agganciati in un numero pari a quattro ventralmente in speciali piloni ed uno ad ogni pilone subalare, sotto la parte fissa della semiala a geometria variabile. Il pieno carico superava i 2 721 kg, quindi era più comune caricare un misto di Phoenix, Sparrow e Sidewinder per ridurre il peso complessivo dell'aereo.

Furono prodotte un totale di quattro versioni dell’AIM-54:

AIM-54A - La prima versione in servizio dal 1974. Una volta lanciato il motore spingeva L'AIM-54A ad una velocità superiore a Mach 2, quindi entrava in azione il sofisticato sistema di guida: per obiettivi non troppo distanti il radar semi-attivo aggiornava continuamente la loro posizione e li marcava periodicamente per dirigere il missile verso di loro; in caso di nemici a grande distanza (fino a 130 km) invece veniva fatta seguire al Phoenix una traiettoria a quote maggiori per ridurre l'attrito e quindi avere più autonomia, finché negli ultimi 18 km entrava in funzione il radar che marcava l'unità da centrare;[2] in caso invece di bersagli vicini (a non meno di 3,7 km) diventava immediatamente operativo il radar;
AIM-54B - Versione prodotta in quantità esigue la cui peculiarità era una semplificazione del processo di produzione rispetto al modello precedente;
AIM-54C - Versione iniziata a produrre dal 1982 dotata di un nuovo sistema di guida con migliorie al pilota automatico e ai software interni, rendendolo più efficace contro bersagli altamente manovrabili come caccia e missili sea skimming. Il motore, più potente, garantiva una maggiore velocità che unita all'introduzione di una nuova spoletta rendevano più letale il Phoenix; gli aggiornamenti tra l'altro proseguirono con l'installazione di una nuova testata più efficace;
AIM-54 ECCM/Sealed - Versione con contro-contromisure elettroniche che non richiedeva più un raffreddamento durante il volo agganciato al vettore. In servizio dal 1988, le sue novità consistevano in una nuova testata esplosiva e in un nuovo software. A causa dell'assenza del sistema di raffreddamento, il Tomcat non doveva superare una certa velocità quando lo portava in volo.

Ci furono anche versioni dedicate all'addestramento e alla sperimentazione designate ATM-54A, ATM-54C e DATM-54A (con carica inerte), AEM-54 (dotata di una particolare telemetria per l'acquisizione di dati) e CATM-54A e CATM-54C (versione non lanciata usata per verificare il sistema di acquisizione del bersaglio).

Il radar AN/AWG-9

Durante il suo sviluppo, una funzionalità chiave dell'F-14 Tomcat era il buon accoppiamento con il suo radar, l'AN/AWG-9 e il missile AIM-54 Phoenix. La combinazione avrebbe fornito l'aereo di un sistema di sorveglianza mai costruito prima, così come di un raggio d'azione eccezionale.

L'AN/AWG-9 fu un apparecchio rivoluzionario per l'epoca, prima della sua introduzione infatti l'operatore era costretto ad interpretare un quadro luminoso analogico per distinguere i veri bersagli dal rumore di fondo, mentre questo radar era uno dei primi con filtro digitale che lasciava all'operatore una visuale molto più chiara dello spazio aereo davanti a lui. Aveva due unità di potenza, tre processori, cinque filtri digitali, quattro unità di controllo radar, tre trasmittenti (capaci di generare un'onda continua a impulsi Doppler) ed un'antenna di 91,4 cm sulla quale era anche montato il sistema IFF formato da due righe di sei dipoli. La potenza del radar era di 10,2 kW.

La capacità più straordinaria dell'AN/AWG-9 era quella di agganciare fino a 24 bersagli simultaneamente, fornendo la posizione di sei di questi ai missili Phoenix. Come i moderni radar Track-While-Scan (TWS, "aggancia mentre continua a scansionare") questo tiene in memoria i dati di ognuno dei 24 bersagli acquisiti, mentre l'antenna continua a cercare, e al passaggio successivo compara le nuove acquisizioni con quelle vecchie aggiornandone la posizione. Lo stesso metodo permetteva al radar di aggiornare i Phoenix mentre erano in volo verso il bersaglio trasferendo via radio i dati del bersaglio appropriato a ciascuno dei missili inviati che avrebbe dovuto aggiustare appropriatamente la sua corsa. Prima del lancio dei missili il radar stabiliva anche una gerarchia tra le minacce che rilevava, aumentando così le possibilità di sopravvivenza dell'aereo lanciatore. Questo radar è poi stato sostituito nelle ultime versioni del Tomcat (D) da una suo evoluzione, l'APG-71, digitalizzato, migliorato e dotato di una portata maggiore (370 km).

ENGLISH

The AIM-54 Phoenix is a radar-guided, long-range air-to-air missile (AAM), carried in clusters of up to six missiles on the Grumman F-14 Tomcat, its only operational launch platform. The Phoenix was the United States' only long-range air-to-air missile. The combination of Phoenix missile and the AN/AWG-9 guidance radar was the first aerial weapons system that could simultaneously engage multiple targets. Due to its active radar tracking, the brevity code "Fox Three" was used when firing the AIM-54.

Both the missile and the aircraft were used by Iran and the United States Navy. In US service both are now retired, the AIM-54 Phoenix in 2004 and the F-14 in 2006. They were replaced by the shorter-range AIM-120 AMRAAM, employed on the F/A-18 Hornet and F/A-18E/F Super Hornet—in its AIM-120D version, the latest version of the AMRAAM just matches the Phoenix's maximum range.

The AIM-54 is credited with 62 air-to-air kills, all scored by Iran during the long Iran–Iraq War. Following the retirement of the F-14 by the U.S. Navy, the weapon's only current operator is the Islamic Republic of Iran Air Force.

Development

Background

Since 1951, the Navy faced the initial threat from the Tupolev Tu-4K 'Bull' carrying anti-ship missiles or nuclear bombs.

Eventually, during the height of the Cold War, the threat would have expanded into regimental-size raids of Tu-16 Badger and Tu-22M Backfire bombers equipped with low-flying, long-range, high-speed, nuclear-armed cruise missiles and considerable electronic countermeasures (ECM) of various types. This combination was considered capable of saturating fleet defenses and threatening carrier groups.

The Navy would require a long-range, long-endurance interceptor aircraft to defend carrier battle groups against this threat. The proposed F6D Missileer was intended to fulfill this mission and oppose the attack as far as possible from the fleet it was defending. The weapon needed for interceptor aircraft, the Bendix AAM-N-10 Eagle, was to be an air-to-air missile of unprecedented range when compared to contemporary AIM-7 Sparrow missiles. It would work together with Westinghouse AN/APQ-81 radar. The Missileer project was cancelled in December 1960.

AIM-54

In the early 1960s, the U.S. Navy made the next interceptor attempt with the F-111B, and they needed a new missile design. At the same time, the USAF canceled the projects for their land-based high-speed interceptor aircraft, the North American XF-108 Rapier and the Lockheed YF-12, and left the capable AIM-47 Falcon missile at a quite advanced stage of development, but with no effective launch platform.

The AIM-54 Phoenix, developed for the F-111B fleet air defense fighter, had an airframe with four cruciform fins that was a scaled-up version of the AIM-47. One characteristic of the Missileer ancestry was that the radar sent it mid-course corrections, which allowed the fire control system to "loft" the missile up over the target into thinner air where it had better range.

The F-111B was canceled in 1968. Its weapons system, the AIM-54 working with the AWG-9 radar, migrated to the new U.S. Navy fighter project, the VFX, which would later become the F-14 Tomcat.

In 1977, development of a significantly improved Phoenix version, the AIM-54C, was developed to better counter projected threats from tactical anti-naval aircraft and cruise missiles, and its final upgrade included a re-programmable memory capability to keep pace with emerging ECM.

Usage in comparison to other weapon systems

The AIM-54/AWG-9 combination had multiple track capability (up to 24 targets) and launch (up to six Phoenixes can be launched nearly simultaneously); the large 1,000 lb (500 kg) missile is equipped with a conventional warhead.

On the F-14, four missiles can be carried under the fuselage tunnel attached to special aerodynamic pallets, plus two under glove stations. A full load of six Phoenix missiles and the unique launch rails weighs in at over 8,000 lb (3,600 kg), about twice the weight of Sparrows, putting it above the allowable bringback load (which also would include enough fuel for go-around attempts). As such, carrying six Phoenix missiles would necessitate the jettison of at least some of the Phoenix missiles if they were not used. The most common air superiority payload is a mix of two Phoenix, four Sparrow, and two Sidewinder missiles.

Most other US aircraft relied on the smaller, semi-active medium-range AIM-7 Sparrow. Semi-active guidance meant the aircraft no longer had a search capability while supporting the launched Sparrow, reducing situational awareness.

The Tomcat's radar could track up to 24 targets in track-while-scan mode, with the AWG-9 selecting up to six potential targets for the missiles. The pilot or radar intercept officer (RIO) could then launch the Phoenix missiles once parameters were met. The large tactical information display (TID) in the RIO's cockpit gave information to the aircrew (the pilot had the ability to monitor the RIO's display) and the radar could continually search and track multiple targets after Phoenix missiles were launched, thereby maintaining situational awareness of the battlespace.

The Link 4 datalink allowed US Navy Tomcats to share information with the E-2C Hawkeye AEW aircraft. During Desert Shield in 1990, the Link 4A was introduced; this allowed the Tomcats to have a fighter-to-fighter datalink capability, further enhancing overall situational awareness. The F-14D entered service with the JTIDS that brought the even better Link 16 datalink "picture" to the cockpit.

Active guidance

The Phoenix has several guidance modes and achieves its longest range by using mid-course updates from the F-14A/B AWG-9 radar (APG-71 radar in the F-14D) as it climbs to cruise between 80,000 ft (24,000 m) and 100,000 ft (30,000 m) at close to Mach 5. The Phoenix uses this high altitude to maximize its range by reducing atmospheric drag. At around 11 miles (18 km) from the target, the missile activates its own radar to provide terminal guidance.[8] Minimum engagement range for the Phoenix is around 2 nmi (3.7 km); at this range active homing would initiate upon launch.

Service history

U.S. combat experience:

On January 5, 1999, a pair of US F-14s fired two Phoenixes at Iraqi MiG-25s southeast of Baghdad. Both AIM-54s' rocket motors failed and neither missile hit its target.

On September 9, 1999, another US F-14 launched an AIM-54 at an Iraqi MiG-23 that was heading south into the no-fly zone from Al Taqaddum air base west of Baghdad. The missile missed, eventually going into the ground after the Iraqi fighter reversed course and fled north.

The AIM-54 Phoenix was retired from USN service on September 30, 2004. F-14 Tomcats were retired on September 22, 2006. They were replaced by shorter-range AIM-120 AMRAAMs, employed on the F/A-18E/F Super Hornet.

Despite the much-vaunted capabilities, the Phoenix was rarely used in combat, with only two confirmed launches and no confirmed targets destroyed in US Navy service. The USAF F-15 Eagle had responsibility for overland combat air patrol duties in Operation Desert Storm in 1991, primarily because of the onboard F-15 IFF capabilities. The Tomcat did not have the requisite IFF capability mandated by the JFACC to satisfy the rules of engagement to utilize the Phoenix capability at beyond visual range. The AIM-54 was not adopted by any foreign nation besides Iran, or any other US armed service, and was not used on any aircraft other than the F-14.

Iranian combat experience

On January 7, 1974 as part of Project Persian King, the Imperial Iranian Air Force placed an order for 424 AIM-54As, later increasing it by 290 missiles that June. Of the initial order, 274 missiles and 10 training rounds were delivered for US$150 million, until the 1979 Revolution ended deliveries and left the remaining 150 missiles embargoed and the additional order of 290 cancelled.

According to Tom Cooper and Farzad Bishop, during the Iran-Iraq War AIM-54s fired by IRIAF Tomcats achieved 78 victories against Iraqi MiG-21/23/25s, Tu-22s, Su-20/22s, Mirage F 1s, Super Étendards, and even two AM-39 Exocets and a C-601. This includes two occasions where one AIM-54 was responsible for the downing of two Iraqi aircraft, as well as an incident on January 7, 1981 where a Phoenix fired at a four-ship of MiG-23s downed three and damaged the fourth.

The US refused to supply spare parts and maintenance after the 1979 Revolution, except for a brief period during the Iran-Contra Affair. According to Cooper, the Islamic Republic of Iran Air Force kept its F-14 fighters and AIM-54 missiles in regular use during the entire Iran–Iraq War, though periodic lack of spares grounded large parts of the fleet at times. During late 1987, the stock of AIM-54 missiles was at its lowest, with fewer than 50 operational missiles available. The missiles needed fresh thermal batteries that could only be purchased from the US. Iran found a clandestine buyer that supplied it with batteries, which cost up to US$10,000 each. Iran received spares and parts for both the F-14s and AIM-54s from various sources during the Iran–Iraq War, and has received more spares after the conflict. Iran started a program to build spares for the planes and missiles, and although there are claims that it no longer relies on outside sources to keep its F-14s and AIM-54s operational, there is evidence that Iran continues to procure parts clandestinely.

Both the F-14 Tomcat and AIM-54 Phoenix missile continue in the service of the Islamic Republic of Iran Air Force. Iran claimed to be working on building an equivalent missile and in 2013 unveiled the Fakour-90, an upgraded and reverse-engineered version of the Phoenix.

Variants:

AIM-54A - Original model that became operational with the U.S. Navy in about 1974, and it was also exported to Iran before the Iran hostage crisis beginning in 1979.
AIM-54B - Also known as the 'Dry' missile. A version with simplified construction and no coolant conditioning. Did not enter series production. Developmental work started in January 1972. 7 X-AIM-54B missiles were created for testing, 6 of them by modifying pilot production IVE/PIP rounds. After two successful test firings, the 'Dry' missile effort was cancelled for being "not cost effective".
AIM-54C - The only improved model that was ever produced. It used digital electronics in the place of the analog electronics of the AIM-54A. This model had better abilities to shoot down low and high-altitude antiship missiles. This model took over from the AIM-54A beginning in 1986.
AIM-54 ECCM/sealed round - More capabilities in electronic counter-countermeasures. It did not require coolant conditioning during flights on board F-14s and not fired (the usual situation). Deployed beginning in 1988. Because the AIM-54 ECCM/Sealed received no coolant, F-14s carrying this version of the missile could not exceed a specified airspeed.
There were also test, evaluation, ground training, and captive air training versions of the missile; designated ATM-54, AEM-54, DATM-54A, and CATM-54. The flight versions had A and C versions. The DATM-54 was not made in a C version as there was no change in the ground handling characteristics.
Sea Phoenix - A 1970s proposal for a ship launched version of the Phoenix as an alternative/replacement for the Sea Sparrow point defense system. It would also have provided a medium-range SAM capability for smaller and/or non-Aegis equipped vessels (such as the CVV). The Sea Phoenix system would have included a modified shipborne version of the AN/AWG-9 radar. Hughes Aircraft touted the fact that 27 out of 29 major elements of the standard (airborne) AN/AWG-9 could be used in the shipborne version with little modification. Each system would have consisted of one AWG-9 radar, with associated controls and displays, and a fixed 12-cell launcher for the Phoenix missiles. In the case of an aircraft carrier, for example, at least three systems would have been fitted in order to give overlapping coverage throughout the full 360°. Both land and ship based tests of modified Phoenix (AIM-54A) missiles and a containerised AWG-9 (originally the 14th example off the AN/AWG-9 production line) were successfully carried out from 1974 onwards.
AIM-54B - A land based version for the USMC was also proposed. It has been suggested that the AIM-54B would have been used in operational Sea Phoenix systems, although that version had been cancelled by the second half of the 1970s. Ultimately, a mix of budgetary and political issues meant that, despite being technically and operationally attractive, further development of the Sea Phoenix did not proceed.
Fakour 90 - In February 2013 Iran reportedly tested an indigenous long-range air-to-air missile. In September 2013 it displayed the Fakour-90 on a military parade. It looked almost identical to the AIM-54 Phoenix. In July 2018 as reported by Jane's, Iran started mass production of the Fakour-90.

AN/AWG-9

The AN/AWG-9 and AN/APG-71 radars are all-weather, multi-mode X band pulse-Doppler radar systems used in the F-14 Tomcat, and also tested on TA-3B. It is a very long-range air-to-air system with the capability of guiding several AIM-54 Phoenix or AIM-120 AMRAAM missiles at the same time using its track while scan mode. The primary difference between the AWG-9 and APG-71 is the replacement of the former's analog computer with all-digital computer. Both the AWG-9 and APG-71 were designed and manufactured by Hughes Aircraft; contractor support is now being provided by Raytheon. The AWG-9 was originally developed for the failed naval F-111B program.

The AN/AWG-9 offers a variety of air-to-air modes including long-range continuous-wave radar velocity search, range-while-search at shorter ranges, and the first use of an airborne track-while-scan mode with the ability to track up to 24 airborne targets, display 18 of them on the cockpit displays, and launch against 6 of them at the same time. This function was originally designed to allow the Tomcat to shoot down formations of bombers at long range.

Operators

Current operators: