Second-Generation Harriers

Photo � Anthony Noble

A close up shot of an RAF Harrier GR.7 (Serial ZG531) during its display at Farnborough in 1992

A close up shot of an RAF Harrier GR.7 (Serial ZG531) during its display at Farnborough in 1992

The success of the Harrier and Sea Harrier led to a second-generation version of the type, the "Harrier II", with development driven by the US. The Harrier II would prove a worthy and more capable successor to the early Harriers, and still remains a valuable military asset in the 21st century.

Harrier II origins

The Harrier was the result of a compromise. The original intent to build a VTOL combat aircraft was focused on the supersonic P.1154 concept, but when that fell through, the existing Kestrel was all that was available. The British took it and turned it into a warplane. Although it had unique capabilities, users were never entirely happy with its limited range and warload. There was definitely room for improvement.

In 1973, British Aerospace and McDonnell Douglas conducted a set of conceptual studies for a bigger and better Harrier, the result of which was the "AV-16A" or "AV-8X", based on the bigger and more powerful Pegasus 15 engine, with plenum-chamber burning. The informal "AV-16A" designation reflected the goal of an aircraft with twice the range and twice the warload of the existing AV-8A. There was also some interest in supersonic performance.

There were a number of potential users for such a new aircraft in branches of both the British and American armed services, but in 1975 the British government zeroed out UK participation. The sticking point appears to have been development costs for the Pegasus 15, coupled with government funding constraints on both sides of the Atlantic. The Pegasus 15 project was abandoned and the international collaboration between MDD and BAE fell apart, for the moment.

This meant in practice that future development of the Harrier had been handed over to MDD. The US Marine Corps liked their existing AV-8As and were sufficiently interested in enhancements, specifically better range and payload capability, to give MDD reason to proceed with the development of an improved Harrier, the "AV-8B". This improved Harrier was more modest than the AV-16A concept, but still added significant improvements, such as a bigger new wing and extensive use of composite materials.

The first two "YAV-8B" prototypes were simply AV-8As with the new composite wing. The first one performed its initial flight on 9 November 1978. Flight tests performed in 1979 provided enough proof of the value of the improved wing that MDD obtained a contract for four development aircraft. However, the Carter Administration made it very clear that the USMC would only get the new aircraft if a "major foreign buyer" (meaning "the UK") was found.

The RAF had been considering in parallel a Harrier upgrade proposed by British Aerospace called the "Big Wing" Harrier. This involved a new and bigger wing made of metal and was also known as the "Tin Wing" Harrier. The wing would have been retrofitted to existing Harrier GR.3s and Sea Harriers. However, in 1980 the RAF evaluated the AV-8B design to see if it would meet their requirements instead.


Comparison of "Harrier" types - AV-8B, TAV-8B & the \

Comparison of "Harrier" types - AV-8B, TAV-8B & the \"Big Wing\" Harrier

The RAF's biggest criticism of the AV-8B was that it could not turn quickly enough to defend itself in air combat. In response, MDD added "leading-edge (wing) root extensions (LERX)", short wing extensions along the air intakes that created vortexes over the wing surface to enhance maneuverability. LERX was fitted to the second development aircraft. The idea was borrowed from the Big Wing Harrier design.

Placated, the British agreed to come on board. The British offered to contribute $80 million USD for general development and $200 million USD for development of features related to their own needs, and to buy at least 60 of the new aircraft. Construction of airframe elements was divided between MDD and BAE, with no overlapping production of components.

The first true AV-8B prototype flew on 5 November 1981, with the other three prototype machines flying by the following summer. The first production aircraft flew on 29 August 1983, and the type began to enter operational service at the end of the year, finally displacing all the AV-8Cs by 1987. The USMC would eventually purchase 200 AV-8Bs. There was some consideration to fitting the new composite wing or some modification of it to first-generation Harriers, but this proved impractical.

The Harrier AV-8B / TAV-8B

Photo US Navy

AV-8B Harrier II+, assigned to the "Bulldogs" of Marine Attack Squadron Two Two Three (VMA-223), prepares for landing on the flight deck aboard the amphibious assault ship USS Nassau (LHA 4)

AV-8B Harrier II+, assigned to the "Bulldogs" of Marine Attack Squadron Two Two Three (VMA-223), prepares for landing on the flight deck aboard the amphibious assault ship USS Nassau (LHA 4)

The AV-8B incorporated many significant improvements, some of which were externally visible, some of which were not. The new "supercritical" composite wing was bigger, by 2.69 square meters (29 square feet), and had reduced sweep, 36 degrees instead of 40. The landing-gear outriggers were moved inward from the wingtips to the middle of the wing. Composites were also extensively used in the construction of the fuselage.

The new wing allowed the AV-8B to roughly double the warload of its predecessors, up to 4.2 tonnes (4.6 tons). This was about the same as the old Boeing B-17, quite a vindication of the Harrier against critics who had claimed that it would never be able to carry anything but a pack of cigarettes. The number of stores pylons was increased from four to seven, with one on the fuselage centerline and three under each wing. Four of the pylons were plumbed for carrying external tanks, and the pylon near each wingtip was wired for a Sidewinder AAM or, using a double launch rack, a pair of them.

There were modest changes in the air inlets and exhaust nozzles. The engine was an uprated variant of the Pegasus 104, the "Pegasus 105" (US-built as the P&W "F402-RR-406") with almost 98.1 kN (10,000 kgp / 22,000 lbf) thrust, as well as digital engine controls. The crude-but-effective bolt-on refueling probe was replaced with a retractable probe on the upper side of the left air inlet, though this new probe could also be removed if desired.

BAe / MDD AV-8B Harrier II
CountryAnglo-AmericanAnglo-American Flag
Wingspan9.24 meters30.33 feet
Wing area22.18 sq meters238.75 sq feet
Length14.12 meters46.33 feet
Height3.55 meters11.66 feet
Empty weight5,820 kilograms12,800 pounds
MTO weight14,100 kilograms31,000 pounds
Max speed1,070 kmh662 mph
Service ceiling15,200 meters50,000 feet
Operational Radius976 kilometers606 miles

Despite the uprated engine and the lower weight, the AV-8B was about 80 KPH (50 MPH) slower than the AV-8A. The Marines didn't care. They wanted a "bomb truck" with greater payload and endurance, not a "hot rod". In compensation, the AV-8B was more agile in air combat than the AV-8A.

The Marines had not thought it worthwhile to replace the twin 30 millimeter Aden cannon fitted to their AV-8A, but it was a nuisance stocking ammunition for the Adens since no other Marine weapon used them, and their rate of fire was also on the low side. The Aden cannon were finally replaced by a single five-barreled 25-millimeter pneumatically-operated Gatling gun, the "GAU-12/U", with a maximum rate of fire of 3,600 rounds per minute and a muzzle velocity of 1,070 meters per second. The weapon itself was stored in one gun pod, while the other gun pod contained 300 rounds of ammunition, with a feed tunnel between the two. When the gun pods were not fitted, they were replaced by a pair of fins known as "lift-improvement devices (LIDs)", which trapped hot gases while in ground effect to improve VTOL capability and reduce exhaust ingestion into the engines.

The AV-8B was fitted with a Sea-Harrier-like raised canopy, with a one-piece wraparound windshield, providing much improved visibility. The pilot sat in a UPC-Stencel Type 10B ejection seat. The cockpit was completely revised. The first-generation Harrier's cockpit was sometimes called an "ergonomic slum", but the Harrier II's new "digital" cockpit was state of the art, based on that of the MDD F/A-18 Hornet. It featured a large HUD and HOTAS controls.

New avionics included a stability augmentation system to make the machine easier to fly, plus a new attack system, the Hughes "AN/ASB-19 Angle Rate Bombing System (ARBS)", which had been proven on the McDonnell Douglas A-4M Skyhawk. ARBS combined a laser spot tracker and TV imager working in concert to provide highly accurate targeting capabilities. System avionics incorporated fiber-optic connections, the AV-8B being one of the first operational aircraft to have such a feature. Defensive systems included two AN/ALE-39 chaff-flare dispensers, an AN/ALR-67 RWR, and the ability to carry an AN/ALQ-126C jammer pod. 174 AV-8Bs were built for the USMC.

As with other Harrier variants, a two-seat conversion trainer, the "TAV-8B", was produced as well, the first flying on 21 November 1986. The TAV-8B has a taller tailfin and only a single stores pylon under each wing. Unlike other Harrier two-seaters, it does not have an extended tailcone. A total of 22 TAV-8Bs were delivered to the USMC.


U.S. Navy photo MCS Leonardo Carrillo

An AV-8B Harrier II from the Spanish aircraft carrier Principe de Asturias (R 11) prepares to land after a live fire exercise

An AV-8B Harrier II from the Spanish aircraft carrier Principe de Asturias (R 11) prepares to land after a live fire exercise

The AV-8B Harrier II was not the end of the story. A modest update, the "Night Attack Harrier II" or "AV-8B (NA)", first flew on 26 June 1987, with a modified standard AV-8B used as the prototype. As the "Night Attack" name suggested, the update provided enhancements for night operations, most importantly a GEC Sensors "forward-looking infrared (FLIR)" imager, housed in a tab on top of the nose, that displayed infrared imagery on a wide-angle HUD.

In addition, the cockpit control layout was revised, with new head-down displays, a digital moving-map system, and blue-green cockpit lighting instead of white illumination for compatibility with night vision goggles (NVGs, known to the Marines as "night vision devices / NVDs"). A new "Pegasus 11-61" engine (US designation "F402-RR-408") was fitted, providing 10% greater maximum thrust, as well as reduced maintenance overhead and longer lifetime. Four additional AN/ALE-39 chaff-flare dispensers were placed on top of the rear fuselage, increasing the load of chaff or flare cartridges from 60 to 180. The Marines also adopted the AN/ALQ-164 jammer pod.

Although earlier Harrier II production had a LERX about 70% of the size of that intended for the Big Wing Harrier, the AV-8B (NA) went to a "100% LERX" like that of the original British design.

The AV-8B (NA) went into service in September 1989. The new Pegasus 11-61 engine proved to have a bug, with the titanium blades scratching the engine walls under certain circumstances, starting an engine fire. This problem had been encountered before, with the P.1127; it was fixed by replacing the titanium blades with steel blades. 61 new-build Night Attack Harrier IIs were built for the USMC.

The next step up was to provide the AV-8B with an improved radar system. The "Harrier II Plus" or "AV-8B+" was similar to the AV-8B (NA) but featured a longer nose containing Hughes AN/APG-65 multimode radar, developed for the F/A-18 Hornet. Costs of the upgrade were shared with Spain and Italy, who were interested in obtaining the type. First flight of the AV-8B+ prototype, modified from a stock AV-8B, was on 22 September 1992.

The AN/APG-65 is a compact, all-digital unit that provides multiple modes for air-to-air and air-to-ground combat, including such capabilities as "track while scan" and terrain-following navigation. The radar had to be equipped with a smaller antenna than that used in the F/A-18 to fit into the Harrier II Plus, and also had to be given software changes and a new circuit board, but these modifications did little to degrade radar performance.

The AV-8B+ featured other modifications as well, such as the addition of a Sidewinder launch rail on the outrigger landing gear fairing. This idea, as will be explained, was invented by the British for their Harrier IIs, and gave the aircraft nine effective stores pylons. The AV-8B+ also has a distinctive lengthened ram-air intake at the base of its tailfin.

27 Harrier II Plus new-build aircraft have been produced for the USMC, with 72 upgrades from older types to be delivered through 2003. The Marines have been trying to find the money for some additional upgrades for attrition replacements. The upgrades have been somewhat painful to fund, as their cost is a major fraction of that of a new build AV-8B+. Fortunately, the effort has been somewhat simplified by the fact that the F/A-18 Hornet has been receiving an upgrade to the even-better AN/APG-73 radar set, allowing the Harrier upgrades to use refurbished AN/APG-65s.

In the late 1990s, the AV-8B+ was qualified to carry the Israeli-designed Rafael / Northrop Grumman "Litening II" targeting pod, featuring a navigation system; an advanced FLIR with zoom capabilities; daylight cameras; a laser spot tracker; and a laser rangefinder and target designator. After the initial buy of 8 Litening IIs, the USMC then acquired 68 "Litening-ER (Extended Range)" pods with improved optical systems. The following discussion will use the "Litening-ER" name for simplicity, though the Marines do retain the Litening II pods.

The infrared laser target designator's spotlighting can be seen through night-vision goggles, which proved handy in helping forward air controllers confirm that a Harrier was marking the right target, and even for other tasks such as marking helicopter landing zones.

Harriers with Litening-ER pods have been used for night reconnaissance, and in 2003 a cheap-and-quick program was begun to upgrade Marine Litening-ER pods with a radio datalink to allow them to relay imagery to ground troops or other users. The Marines want to obtain more Litening-ER pods. The pod has a great deal of growth potential and the Marines would like to add other improvements, such as a software-based "automatic target recognition" capability. They would also like to integrate the pod more tightly to the aircraft. The initial integration was simple, with the video feed from the pod simply emulating the video feed from a Maverick missile.

The Marines have a list of other enhancements for their Harrier II Plus machines, outlined under the "Open System Core Avionics Requirement (OSCAR)" program announced in 2000, but in reality the USMC has been slow to implement them. High on the list is AMRAAM carriage; plus a MIL-STD 1760 munitions control bus to support the "Joint Direct Attack Munition (JDAM)" GPS-guided bomb; and the "AIM-9X" advanced Sidewinder follow-on with "off-boresight" targeting capability, along with a helmet-mounted sight, the "Joint Mounted Cuing System (JMCS)", to cue the AIM-9X and the Litening-ER pod. The Marines would also like to support the "AGM-154 Joint Standoff Weapon (JSOW)" standoff glide bomb; fit a "Link 16" datalink; and obtain modernized cockpit displays.

The Marines fielded two ground-based Harrier squadrons to the Gulf War in early 1991, the type being one of the first USMC aircraft into action. They also flew a detachment operating off the assault ship USS SAIPAN. A total of 86 AV-8Bs were committed. The AV-8B (NA) was still being introduced at the time and did not participate.

The USMC Harriers performed 7.7% of the sorties in the war. Their effectiveness met the expectations of their owners, though five were lost. They flew missions with standard "dumb" ordnance, including general purpose high-explosive bombs, napalm bombs, and cluster bomb units, as well as "smart" weapons such as laser-guided Maverick missiles. "Buddy" laser designation was provided by OV-10 Bronco and later F/A-18D Hornet forward air controllers, since the USMC Harrier IIs did not have such a capability at the time.

Although the Harriers have their detractors in the USMC who pointed to the losses as indicating the type's vulnerability, with the four-nozzle exhaust configuration giving heat-seeking missiles a dead-center target, General Norman Schwarzkopf, the Coalition theater commander, claimed it was one of the nine weapons that won the war, the other aircraft in the list being the AH-64 Apache helicopter and the F-117 Stealth Fighter.

Funding problems during the 1990s forced the USMC to neglect their Harriers, and problems with the Pegasus engine grounded a good portion of the fleet, forcing the Marines to drop the AV-8B+ from their war plans for a time. However, the problems were addressed, if slowly, and USMC Harrier IIs saw action in the Afghanistan campaign in the winter of 2001:2002, operating from the assault ship USS PELELIU at sea and performing strikes with dumb bombs, providing support for Marine special operations forces operating in the country.

USMC Harriers also fought in the US invasion of Iraq in the spring of 2003 and made good use of their new Litening-ER pods, employing them for both targeting and reconnaissance. The new video-feed feature was very handy, since it allowed forward air controllers to see what the Harrier pilots were seeing, and tell the pilots where friendly and hostile forces were. However, the video feature had only been implemented on three pods when the conflict began, and so those three pods were in great demand.

The Marine Harriers operated from forward bases behind the battle lines and were capable of responding to requests for air support within minutes. Mission-capable rate was almost 80%, demonstrating that the USMC's work to bring the Harrier up to spec had been successful. The general consensus in the USMC was that the Harrier's service in the "Second Gulf War" was outstanding.

The AV-8B was also the focus of a number of export sales. The Spanish Navy, having had good experience with their AV-8S Matadors, bought 12 "EAV-8Bs" for their new carrier, PRINCIPE DE ASTURIAS, with the aircraft assembled by the CASA company of Spain. Similarly, the Italians obtained a useful naval air capability by purchasing 16 Harrier II Plus fighters and two TAV-8Bs for their new carrier, the GUISEPPE GARIBALDI. 13 of these aircraft were assembled by Alenia.

There was some squabbling between the USMC on one side and the Spanish and Italians on the other over Harrier II weapons qualification. Although the new AN/APG-65 radar of the AV-8B+ was capable of supporting BVR air combat using AMRAAM, or "over the horizon" surface attack using the AGM-84 Harpoon antiship missile, the Marines were slow to qualify AMRAAM and showed little interest in qualifying the Harpoon. The Spaniards and Italians did want these capabilities, which would give their AV-8B+ Harrier IIs a substantially nastier bite, and in fact apparently believed when they helped fund the integration of the AN/APG-65 to the Harrier II that adding such capabilities was the specific point of the exercise.

Apparently AMRAAM has been qualified for use by Spanish and Italian Harriers through a software upgrade to the AN/APG-65, though the USMC still hasn't qualified the missile. Since Harpoon support seems to have little prospect of happening, the Spaniards are looking at supporting the Norwegian Kongsberg "Penguin" antiship missile, while the Italians are considering support of their own Alenia "Marte 2" antiship missile.

With the acquisition of McDonnell Douglas by Boeing in 1998, the AV-8B family has, at least technically, become the "Boeing Harrier II". Boeing never built any Harriers, however: the Saint Louis production line was shut down and dismantled.

HARRIER GR.5 / GR.7 / GR.9 / T.10

Photo � Anthony Noble

Harrier GR.7 (serial ZD379) seen here close up during a display at Farnborough Sept 1990

Harrier GR.7 (serial ZD379) seen here close up during a display at Farnborough Sept 1990

The British equivalent of the AV-8B was the "GR.5", the designation originally given to the unbuilt "Big Wing" Harrier. The GR.5 as it was actually built was generally similar to the AV-8B, but with many detail changes. The GR.5's changes from the AV-8B configuration ended up being uncomfortably expensive and have been criticised, with the response being that the RAF had different requirements than the USMC, and the changes were needed to allow the aircraft to meet RAF operational needs.

Instead of one 25 millimeter Gatling gun, the GR.5 was to be fitted with twin new-design 25 millimeter Aden revolver cannon, each with a rate of fire of up to 1,850 rounds per minute and a muzzle velocity of over 1,000 meters per second. However, this piece of gear would prove particularly troublesome. As mentioned, the RAF also came up with the straightforward idea of adding a Sidewinder launch rail under the landing-gear outriggers, and the British aircraft incorporated additional protection against bird strikes to support low-level operations.

The GR.5 also has a somewhat different avionics kit than the AV-8B. Although the British were happy to retain the AV-8B's ARBS, they did incorporate a Ferranti moving-map display, their own radio and IFF systems, and fitted entirely different countermeasures. The countermeasures kit included a Marconi Zeus ECM system, a Plessey "Missile Approach Warning (MAW)" system, and Swedish Bofors BOL chaff dispensers. The Zeus included an RWR that could identify 1,000 different types of emitters and activate its self-defense jammer automatically to meet a specific threat. The MAW could automatically dispense chaff when a missile attack was detected.

The GR.5 was to be fitted with an infrared camera for all-weather reconnaissance in addition to the FLIR and was designed with a chin housing for it, but this project was cancelled and the chin housing remained empty.

The first GR.5 flew at Dunsfold in the UK on 30 April 1985, with formal introduction to operational RAF service in 1989, replacing the GR.3. 41 GR.5s were built, followed by a batch of 21 "GR.5As" that were generally similar to the GR.5 but had minor modifications to make them easier to convert to the next mark, the "GR.7".

The GR.7 was the RAF equivalent of the Night Attack Harrier II, though it used British-specified avionics, with a GEC-Marconi 1010 FLIR in a small fairing on top of the nose; a Smiths Industries wide-angle HUD; a GEC-Marconi color map display; updated mission software; and an NVG-compatible cockpit.

The Martin-Baker Mark 12 ejection seat was updated to a Type 12 Mark 2 ejection seat, which has a connection to the pilot's helmet to blow off his NVGs with a compressed-air charge before ejection. This is done because otherwise on ejection the unbalanced weight of the NVGs can break the pilot's neck, or they can snap off and smash into the pilot's lap. USMC Harriers do not have any provision for automatically discarding an NVG during ejection.

The GR.7 is otherwise much like the GR.5. The initial GR.7 prototype flew on 20 November 1989 and the type began to flow to operational squadrons in late 1990. 34 new-build GR.7s were built, and 58 GR.5s and GR.5As were upgraded to GR.7 specification. Although all GR.5 and early GR.7 production featured the 70% LERX, the 17th new-build GR.7 featured the 100% LERX, and earlier production was retrofitted with it.

The RAF's updated Harrier force was initially committed to "combat" of sorts in 1992, when they participated in OPERATION WARDEN, the British effort alongside the US OPERATION PROVIDE COMFORT, which was supposed to help protect Kurds in northern Iraq from Saddam Hussein. In fact, the RAF Harriers did little more than monitor Saddam Hussein's violations of the northern security zone.

This embarrassing exercise did result in restoring a reconnaissance capability to the Harrier Force, which had been lost with the gradual withdrawal of the Harrier GR.3 from service. The new Harriers were initially fitted with the old reconnaissance pods, which turned out to be a troublesome exercise since it required a good deal of rewiring of the aircraft and training of the pilots for the reconnaissance mission. The old pods have been subsequently replaced with more modern Vinten reconnaissance pods of various types.

The RAF Harrier force was relieved of duty in OPERATION WARDEN by Tornados, but then, following up the service of British first-generation Harriers in the Balkan Wars, they were assigned to patrols over Bosnia in July 1995. They participated in air strikes as part of OPERATION DELIBERATE FORCE, the air campaign against Serb military targets from 30 August to 14 September 1995.

Beginning in 1997, the GR.7 has been operationally deployed on Royal Navy carriers, providing strike capabilities while the Sea Harrier FA.2 ensures air superiority. This arrangement of course walks in the path of the Harrier GR.3 carrier deployments in the Falklands War and for a few years following. However, it has now become a much more official British policy, established with the formation of "Joint Force Harrier" in 2000, in which the RAF and Royal Navy Harriers are being gradually assembled into a common command structure as part of the British military's "Joint Rapid Deployment Force".

GR.7s have been provided with minor improvements for carrier operations, including a cockpit-mounted GPS receiver, presumably the Garmin 100 as used in the Shar; software improvements to the aircraft's INS to ease alignment on a rolling carrier deck; a new IFF transponder; and shift of the water replenishment point from the top of the aircraft to inside the undercarriage bay so that flight-deck crews would have easier and safer access.

Embarrassingly, the GR.5 was never fully combat-capable and the GR.7 was only fully combat-capable in the mid-1990s. Although BAE had qualified a range of stores for these aircraft, the RAF had to perform their own qualifications, and the service dragged their feet on the matter. Part of the problem appears to have been bugs in aircraft system software that took a long time to work out.

Even as late as 1997, a senior RAF officer had to admit that "the aircraft is still getting clearances," though by that time the worst was well over. However, observers have noted that there are no images of any RAF Harrier II fitted with the 25 millimeter cannon. It appears that the problem was not with the aircraft, but with production of the cannon. There had also been waffling on support of the TIALD advanced targeting pod, which allowed the GR.7 designate its own laser-guided bombs, but this issue was resolved by the mid-1990s and TIALD was used by GR.7s to good effect over the Balkans.

After the NATO Kosovo air campaign in the spring of 1999, which demonstrated a greater need for a stand-off precision guided munitions, the RAF decided to qualify and support the US "AGM-65D2G Maverick" imaging infrared air-to-surface missile on the GR.7. Qualification trials were performed in 2000 and proved straightforward, as the Maverick had long been used on USMC Harrier IIs.

RAF Harrier GR,7s provided air support during the Anglo-American invasion of Iraq in the spring of 2003. Some of the aircraft carried Mavericks and improved "GPS enhanced" Paveway II laser-guided bombs, while a few carried a digital reconnaissance pod inherited from the Jaguar GR.3. Interestingly, Coalition cooperation was so tight that the GR.7s were mainly tasked with support of the US Army V Corps, though 30% of the Harrier missions were conducted in support of the USMC and British ground forces.

The establishment of Joint Force Harrier and the desire to provide the GR.7 with improved capabilities led the UK to begin a program to upgrade the variant to a new "GR.9" specification.

The path to this decision was somewhat convoluted. A GR.9 variant, roughly comparable to the USMC Harrier II Plus, had been considered for a number of years but had never made the cut. However, an engine update, in which 30 GR.7s were to be refitted with the "Pegasus 107" engine, was begun in the mid-1990s. The Pegasus 107 provides 196 kN (10,800 kgp / 23,800 lbf) thrust, 8% more than the Pegasus 105, and has improved reliability and ease of maintenance.

There was also a concern in the RAF with the fact that various upgrades had been applied in an inconsistent fashion across their Harriers, making maintenance troublesome, and suggesting the need to bring up all the Harriers to a uniform spec.

The pressures towards updating the GR.7 finally reached a flashpoint with the establishment of Joint Force Harrier. The authorities decided that a mixed force of RAF GR.7s and FAA Shars simply wasn't on. As mentioned in the previous chapter the Shars were to be phased out by 2006, and both the RAF and the FAA would operate a common, improved Harrier II type.

This common type will be the GR.9, with 60 GR.7s to be upgraded to this spec. The core of the upgrade will be a MIL-STD 1760 weapons databus and a new main computer system with modernized weapons software; a new GPS-INS navigation system; a ground-proximity warning system; and improved cockpit displays. 16 of the GR.9s will be fitted for carriage of the TIALD pod.

The 30 GR.7s being fitted with the Pegasus 107 engine will be upgraded to GR.9 specification and designated "GR.9A". It appears that at least ten more GR.7s may now get the improved engine.

The improved fire-control system of the GR.9 will permit use of the new Marconi "Brimstone" anti-armor missile, an advanced derivative of the US Hellfire weapon; the "Advanced Short-Range AAM (ASRAAM)", a British successor to the traditional Sidewinder AAM with "off-boresight" targeting capability and comparable to the AIM-9X; and possibly the new "Storm Shadow" cruise missile.

The GR.9 will not have the long-range air-to-air radar needed to support AMRAAM. It will have a potent close-in air combat capability with ASRAAM, though GR.9 pilots will not have the helmet-mounted sight needed to make the best use of the missile. The retirement of the Shars with their AMRAAMs has left a gap in fleet air defense, but this is expected to be plugged until the arrival of the F-35 JSF by the new Royal Navy "Type 45" air-defense escort destroyer, with the Aster / PAAMS surface-to-air missile system.

While the British considered an interim two-seat "T.6" trainer type, built by upgrading existing T.4s, to support GR.5/7 pilot training, on consideration such a measure did not seem very effective from either a cost or training point of view. They instead went to the TAV-8B with British avionics and called it the "T.10". The T.10, unlike the TAV-8B, is fully combat-capable. Initial flight was on 7 April 1994, with introduction into RAF service in March 1995. A total of 14 were acquired.

U.S. Navy photo MCS 2nd Class D. Keith Simmons

The F-35 Joint Strike Fighter Lightning II, built by Lockheed Martin takes off for its first flight to test the aircraft’s initial capability at Joint Reserve Base Fort Worth.

The F-35 Joint Strike Fighter Lightning II, built by Lockheed Martin takes off for its first flight to test the aircraft’s initial capability at Joint Reserve Base Fort Worth.

BAE performed a number of studies of improved versions of the Harrier, then went on to consider a number of new-design V/STOL machines, some of them very exotic-looking. The ultimate decision was to join forces with the US on the F-35 JSF.


Several ingenious ideas were promoted by Harrier enthusiasts in the post-Falklands period to use the Harrier as a naval "force multiplier", based on unconventional replacements for a traditional aircraft carrier.

One was called the "shipborne containerized air-defense system (SCADS)". This was a clever idea by which all the equipment needed to put together the operational apparatus of a small ski-jump Harrier carrier -- including living quarters, fuel and munitions storage, maintenance facilities, missile and decoy launchers, antisubmarine helicopter facilities, and of course a ski-jump deck -- would be built in a modular fashion, based on the standard container sizes used on container ships, and put in storage. The entire kit could be assembled in about two days on a container ship when needed, with provisions for 30 days of operation without resupply. The kit would be removed and stored again when the emergency was over.

An even cleverer idea was the "Skyhook". This concept was to use a crane that could be mounted on a small ship, such as a helicopter frigate, to lift Harriers off the deck and allow them to fly off, and then recover them later. On recovery, they could be returned to their deck hangar, or refueled while they dangled on the crane, and released to continue operations. The crane would be "smart", with stabilization capabilities and a panel indicator mounted to give the Harrier pilot location information. With such a system, even a helicopter frigate could operate four Harriers as a kind of "mini-carrier".


the "Skyhook" concept that would allow such aircraft to operate in the VTOL mode from ships without any form of aircraft deck

the "Skyhook" concept that would allow such aircraft to operate in the VTOL mode from ships without any form of aircraft deck

While British Aerospace experimented with the Skyhook on land using their G-VTOL demonstrator, neither SCADS nor the Skyhook became realities. Critics suggested that they implied a dispersal of forces that made logistics impractically difficult. They still remain interesting ideas to be kept in mind for the future of STOVL combat aircraft.

Another experimental evaluation program focused on the Harrier has been conducted by the British military researcher establishment, This program is focused on making STOVL flight simpler for the pilot, and involves a modification of the second T.2 prototype with the tortured designation "Vectored-thrust Aircraft Advanced flight Control (VAAC)".

The VAAC Harrier is intended to consider solutions to the "three hands" problem of flying the type, where the pilot must handle throttle, stick, and nozzle angle lever during takeoff and landing. The VAAC Harrier was fitted with a new cockpit and control system to allow the aircraft to be flown by pilots without special training.

The control system was installed by the Cranfield Institute of Technology, Britain's foremost academic institution for aviation research. The T.2 was delivered to Cranfield in 1983, the modified aircraft made its first flight in 1985, and Cranfield handed it back to the Royal Aircraft Establishment for tests in 1986.

The aircraft still looks like a normal T.2 externally, except for the replacement of the cannon pods with featureless pods containing test avionics. The rear seat was given the new layout, while the front seat retains the old T.2 control layout. This allows the aircraft to carry a test pilot in the back seat and a "safety pilot" in the front seat who can take over if the new control system does something outside of the script.

The VAAC Harrier was designed to be easily modified to allow testing of different cockpit layouts, control systems, and software, and it has been through many modifications. As of 1995, the program came under the jurisdiction of the new British "Defence Evaluation & Research Agency (DERA)", which absorbed the RAE, though DERA has now been disbanded into two new organizations, a commercial organization named "QinteQ" and a government organization named the "Defence Science & Technology Laboratory (DSTL)". It is unclear which organization inherited the VAAC Harrier.

The VAAC Harrier is strictly an experimental program and was not intended as a prototype for another Harrier update as such. However, it has proven extremely useful for evaluating technologies to be used in the F-35 JSF.

Harrier Production History

As the variant and production history of the Harrier is a little convoluted, it is useful to provide a summary. The table uses the following abbreviations:

  • IDNV: Indian Navy
  • ITNV: Italian Navy
  • SPNV: Spanish Navy
  • USMC: US Marine Corps

Aircraft described as "Harriers" without a nation code are implied to be British Royal Air Force, while "Sea Harriers" are implied to be British Royal Navy.

Harrier Production History
Harrier VariantNew Build / conversions
Hawker P.11276
Hawker Kestrel F(GA).19
Total Experimentals15
Harrier preproduction6 / never fielded operationally
Harrier GR.161
Harrier GR.1A17 / plus updated GR.1s
Harrier GR.340
USMC AV-8A (Mk.50)102 / 47 updated to AV-8C standard
SPNV AV-8S (Mk.53 & 55)11 / AKA VA-1, 7 sold to Thai Navy in 1997
Total single-seat Harrier237
Harrier T.2 protos2
Harrier Mk.521 / Hawker G-VTOL demonstrator
Harrier T.210
Harrier T.2A4 / plus updated T.2s
Harrier T.411
Harrier T.4A1
Harrier T.4N3
Harrier T.80 / 7 conversions from older marks
USMC TAV-8A (Mk.54)8
SPNV TAV-8S (Mk.56)2 / AKA VAE-1, both sold to Thais in 1997
IDNV Harrier T.604 / plus 2 updated T.2s
Total Harrier trainers46
Sea Harrier protos 3
Sea Harrier FRS.154
Sea Harrier FRS.218 / plus 33 updates from FRS.1
IDNV Sea Harrier FRS.5123 / similar to FRS.1
Total Sea Harrier98
Total GEN-1 HARRIER381
USMC AV-8B+27 / plus 72 upgrades
SPNV AV-8B+8 / plus 10 upgraded SPNV AV-8B
Harrier II protos2
Harrier GR.541
Harrier GR.5A21
Harrier GR.734 / plus 50 upgraded GR.5s & GR.5As
Harrier GR.9 / GR.9A- / projected 60 upgrades from GR.7s.
Total single-seat Harrier II396
Harrier T.1013
Total Harrier II trainers38

Comments on the Harrier

The Harrier is an interesting study in technology. While it was a remarkable invention in itself, its development progressed though a maze of bureaucratic obstacles, guided by a handful of visionaries who saw its potential.

Most of the time, it went forward only by virtue of being the only available compromise. What the end users really wanted was a supersonic aircraft, and settled on the subsonic Harrier only when plans for bigger and faster aircraft fell through. Nonetheless, the design proved effective and adaptable, and a source for a lot of interesting ideas.

Despite its limitations, it has been a great success, with an operational history of three decades, hundreds of aircraft produced, and users with the armed forces of five nations. However, despite the obvious benefits provided by STOVL for keeping strike aircraft handy near the front lines and dispersed from easily-attacked air bases, as well as to allow countries with limited resources to operate an effective naval air arm, it remains unique in Western arsenals.

It is surprising that change and growth in the field of STOVL aircraft has been so excruciatingly slow, only now resulting in the emergence of a second-generation operational STOVL fighter, the F-35 JSF. The JSF will eventually mean the end of the Harrier line, after over 30 years of tweaking and modification -- but as the new British GR.9 program shows, there's life left in the Harrier yet.

Author: Greg Goebel

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