Testing for War

WHAT’S NEW IN the world of RAF attack aircraft? Squadrons may claim that their aircraft are to the latest operational standards, but by the time that a new piece of kit is fitted to a Tornado or Harrier it will be well familiar at Boscombe Down. Famous as the base of the MoD PE’s Aircraft & Armament Evaluation Establishment’, this Wiltshire aerodrome is also host to an RAF unit dedicated more to operational development than test flying and aircraft handling. The Central Tactics & Trials Organisation (CTTO) reports to HQ Strike Command at High Wycombe and directly controls its own colocated flying element, the Strike/Attack Operational Evaluation Unit (SAOEU).

CTTO’s role is to act as a bridge between the RAF’s units and its high command. It advises the Air Staff on operational employment of resources and simultaneously advises aircrew on the use of weapon systems. Such duties were last undertaken by the Fighter Command Trials Unit until its disbandment at Binbrook on June 30, 1967 and Strike Command

Development Unit, which stood-down at Finningley on December 31,1968.

This left the Tactics Branch (which became the CTTO when Strike Command formed on April 1, 1968) without dedicated airborne support. Growing complexity of modern aircraft forced a reappraisal of operational trials requirements, and on March 25, 1983 the Vice-Chief of Air Staff announced the need for a Tornado Operational Evaluation Unit, «because the TWCU or the front-line squadrons do not have the resources to undertake more than the occasional small-scale trials.»

He added that, «To be effective, the OEU requires the closest co-ordination of flying, technical and analytical effort, and this can only be achieved at Boscombe Down.» Accordingly, the TOEU was officially opened by AM Sir Peter Bairsto on September 1, 1983, with W/C John G Lumsden, OBE, in command and a strength of four Tornado GR.ls. W/C M W Raz Ball took over in December 1985, followed by W/C Keith Grumbley on July 8, 1988 and W/C Dave Keenan on September 16, 1991. Reflecting the formation of a Tornado F.3 OEU at Coningsby on April 1, 1987 and plans to add a Harrier GR.5 task, the TOEU became the SAOEU on October 5, 1987. Its first Mk 5 (ZD328) was delivered on July 26, 1988. Today, SAOEU has a strength of three Tornado GR.ls, three Harrier GR.7s (first -ZG473 — delivered August 17, 1990), two ‘Nightrider’ Harrier T.4As and a ‘Nightcat’ Jaguar T.2A. Its hangar also houses Sea Fury VZ345, rebuilt after a landing accident on April 17, 1985 but not officially cleared for a return to flying until a programme of nondestructive testing can be accomplished. A small flying staff comprises two Tornado crews (S/Ls Bruce Chappie, Steve Cox and Dave James and F/L Gary Ancell) and three Harrier pilots (the CO, plus F/Ls Steve Hawkins and Paul Gunnel).

At least one of the Tornado pilots must be a Qualified Weapons Instructor and one of the back-seaters must be a graduate of the Air Systems Course. CTTO, formerly at High Wycombe, has been at Boscombe Down for five years, its commandant being the above-mentioned John Lumsden. The CTTO badge of three swords in pall (ie, a Y-shaped pattern) is applied to SAOEU aircraft as the unit has yet to devise a badge of its own.

Tornado Trials

Tornado and Harrier trials work tends to be undertaken separately, although there are areas of common interest, such as night vision systems. The Gulf War resulted in an upsurge of activity on the Tornado front, including a deployment to Eglin AFB between September 11 and November 2, 1990 to test-drop the new Thorn-EMI Multi-Function Bomb Fuze before its first operational use on 1,000lb bombs in Desert Storm. The opportunity was also taken to conduct some electronic warfare trials in the USA.

Electronic warfare was a preoccupation during the build-up to Desert Storm, particularly because Iraq possessed some defensive systems which in Europe were only used by friendly forces. Countermeasures to these had to be devised. It was also necessary to ensure that the Tornado’s jammers were able to work satisfactorily at medium altitude. Jamming aerials devised for low altitude missions (where there was minimal risk to the underside of the aircraft) had to be checked to ensure that they still gave all-round coverage when the Tornado was more exposed. The GEC-Ferranti TIALD laser-desianator pod was worked up to operational standard at breakneck speed for highly successful use in the latter part of Desert Storm.

As for the JP233 airfield-denial weapon used in the early attacks on Iraqi bases, that had been tested in the USA in 1988 and slightly modified as a result of the SAOEU’s findings. Newsreel of Tornado GR. 1s landing after their first missions in Desert Storm showed them wearing the F.3’s larger 2,2501 drop-tanks for the first time, but the fitment was old news at SAOEU, one of whose aircraft had flown unrefuelled to Goose Bay using these tanks in 1989. The OEU had also designed the ‘system’ (actually nothing more complex than a metal stop) to prevent the wings being swept more than 63 — four degrees short of maximum — with big tanks fitted. Results of operational experience in the Gulf generated new tasks for the OEU Tornado fleet, and as a consequence the aircraft will have improved capabilities of attack and self-defence at medium altitude.

In preparation for the Tornado GR.4 upgrade programme, trials will shortly begin of a Tornado with a forward-looking infra-red (FUR) vision system (podded, rather than in the definitive under-fuselage blister). Tornado workload will increase when the first Mk 4s are delivered, although the Harrier GR.7 tasking will then be starting to reduce. Reflecting these swings of emphasis, the last two COs (Grumbley and Keenan) have been «Harrier men», whilst the next -in 1994 — will again come from the Tornado world.

Night Harrier

Recent introduction of the Harrier GR.7 has given the RAF the potential for night operations with passive vision systems. SAOEU is making certain that fullest use can be made of this capability, its research tools also including the two T.4As and the Jaguar.

The night trials team began flying with night vision goggles (NVG) and FLIR in December 1990. In March-April 1991 they visited the US Marine Corps at Yuma MCAS, Arizona, to look at American use of the Night Attack version of AV-8B operated by VMA-211 and conduct their own trials. By the end of the UK night flying season in May the three had amassed 70 hours of flying and dropped practise bombs from 200ft.

Although 3 and 4 Squadrons in Germany have GR.7s, they have not been cleared for night operations. Even the A&AEE was second to SAOEU in using FLIR and NVGs, its own trials having begun in September 1991 with a view to achieving C(A) clearance during 1992. Having determined the best methods of using the new systems in combat, SAOEU passes recommendations back to the CTTO for incorporation in the Harrier tactical manual.

The current three Mk 7s are standard except for a Video 8 camera mounted on the left side of the cockpit, viewing the instruments. The optional under-fuselage strokes are installed instead of the gun pods and the GEC-Ferranti FIN 1075 inertial navigation system is fitted -this having been temporarily replaced in early Harrier GR.5s by a Litton AN/ASN-130 due to reliability problems.

Contrasting with the above, the two tandem-seat Harriers are far from conventional. XW267 is the ‘Nightbird’ Harrier which pioneered night vision systems in a STOVL aircraft but has now transferred equipment to its companion. XW269, like ‘267, has been fitted with a MIL STD 1553B digital databus and switches on the left side of the cockpit coaming for regulation of lighting. It also has a non-standard GEC-Ferranti FD4512 HUD with integrated ‘up-front’ control panel in each cockpit as well as a Tornado-type moving map display from the same manufacturer. Each instrument panel hos a video screen for imagery from the FLIR. Symbology in the HUD and FLIR can be switched to represent that of either a conventional RAF fast jet or the modified GR.5/7 format used for STOVL.

GEC Sensors ‘C’ model FLIR avionics are installed in the rear equipment bay, but XW269’s most prominent external changes are an infra-red linescan in place of the nose-mounted laser-ranger and a second airflow direction vane in the same area. XW267 has been transferred to Farnborough to be the first of the two aircraft refitted with a new inertial navigation unit and video recording system. Both were due to be transferred to the front line late in 1992. According to a recent report, however, pilots are quickly able to adapt to the fuzzy green image seen through NVGs, so familiarization sorties in the T.4 may no longer be deemed essential before single-seat night flying.

The unit’s two-seat Jaguar T.2A is also fitted with a databus and carries a 2321b GEC Sensors Atlantic FLIR pod on the port outer pylon. Indicating Airborne Targeting Low-Altitude Navigation Thermal Imaging, the Atlantic pod is partnered by a HUD displaying FUR imagery and cockpit lighting compatible with pilot’s night vision goggles. The Jaguar was modified in 1990 to provide a means of gaining operational experience of FLIR for the Harrier GR.7 and Tornado GR.4 programmes. The thermal imager and signal processor in the pod are the same as those to be mounted internally in those aircraft — and are already used by the USMC Night Attack AV-8B.

The RAF’s first Harrier mission with NVGs was flown by the SAOEU on December 11,

1990 ond the first representative night attack sortie took place on February 19, 1992 when two aircraft flew 300 miles to drop live 1,000lb bombs on Garvey Island range, northern Scotland. F/Ls Paul Gunnell and Steve Hawkins took off from West Freugh for the test, the lead Harrier having the benefit of being the first GR.7 fitted with a Global Positioning System integrated with the INS. Using NVGs and the fixed FLIR, weapon delivery took place in darkness at 250 ft with an accuracy of under 100ft.

Service liaison

Major tasks like FLIR integration ore assigned to SAOEU by the CTTO, but many of the smaller trials ore self-generated in response to a perceived need. As part of a programme of continuous liaison with squadrons, OEU staff regularly visit operational stations (Gutersloh and Wittering for the Harrier) to lecture and fly training missions — both to understand requirements by gaining first-hand experience and to maintain their own tactical currency. Since 1983, the SAOEU has been assigned nearly 120 tasks, of which two-thirds have been completed:

Tasks Complete In analysis In progress

Tornado 95 71 16 8

Harrier 20 9 4 7

Jaguar 3 3 0 0

Tasks assigned may be as diverse as evaluation of a specific piece of equipment or an ongoing series, such as evaluation and improvement of weapon-aiming. The latter, dependent to a large extent on software which is updated throughout the aircraft’s lifetime, uses Royal Aerospace Establishment facilities at nearby Larkhill if practise bombs or electronic scoring are to be used. Real bombing missions are flown from DRA West Freugh and air-to-air missile trials at DRA Aberporth. Data from each sortie can be offloaded onto disc for laboratory analysis.

A recent trial of a new piece of kit concerned the Vinten VICON 18 Mk 403 reconnaissance pod (as used by USMC AV-8Bs) containing IR linescan and traditional wet film cameras. Some four or five months after the concept was generated by Operational Requirements Branch, clearances had been received and the pod was fitted to a Harrier for a short series of six sorties by SAOEU. Missions were flown at differing speeds and altitudes against a variety of realistic targets on different terrain (taking advantage of an army exercise).

The Joint Air Reconnaissance Interpretation Centre at Brampton was brought in to assess the quality of the imagery. On completion of the flying phase, one month was allowed for compilation of a report defining the pod’s capabilities and operational parameters, plus a further month for CTTO’s publication and circulation of the findings.

A longer trial, now complete, was of the GEC-Morconi Zeus self-protection jamming system for the Harrier. Three GR.5s were detached to Naval Weapons Center, China Lake, in the early Summer of 1989 as Operation Horsefly. They generated 50 sorties against a variety of threats, then finished their Stateside deployment by flying against USMC AV-83s on the air combat manoeuvring range at MCAS Yuma. Detachments to the USA tend to be popular.

Versatile engineers

Technical support of SAOEU must be first rate, in view of the diversity of aircraft types and plethora of one-off installations. In this respect, only the A&AEE’s Fixed-Wing Test Squadron gives its engineers and avionics staff a more demanding time — although, that said, its sortie rate is far lower than the OEU’s. Led by S/L Francis Fisher, about 50 ground personnel maintain the SAOEU fleet, of necessity relying on the RAF and BAe/Panavia for support. Spare parts have to be collected from Wittering (Harrier), Honington or Marham (Tornado) and Coltishall (Jaguar), whilst overhauls of Minor level and above are assigned to Wittering, Honington and St Athan (Jaguar).

To use correct terminology, OEU aircraft rarely undertake trials of ‘Mods’. The Service Engineering Modification (SEM) is a change to the aircraft, designed by the operating service and ratified by the design authority (ie, usually BAe) through o Configuration Control Document.

A Mod is applied to all aircraft of that type in service. New kit at Boscombe Down is installed only on one or two aircraft and may not even find its way to the squadrons; this is the Special Trial Fit. An STF is an engineering change to meet a specific requirement, which is approved by the Commandant of the CTTO as a deviation from the C(A) release for only a designated period of testing. Of course, if all is successful, the STF will progress to being a Mod when it is generally adopted.

In the case of the Vinten recce pod, the manufacturer certified the equipment suitable for carriage on a Harrier and A&AEE gave aerodynamic clearance, relying on its experience of aircraft performance with similar centreline stores. BAe issued structural clearance (by confirming that the pod would not overstress the mounting when flown within the envisaged flight envelope) and provided flight clearance. SAOEU designed cockpit switches and wiring to the pod, consulting with BAe over such aspects as provision or sufficient electrical power for the installation without detriment to other equipment. Quite clearly, being stationed at Boscombe Down greatly expedites the OEU’s work.

Seeing the way ahead

One of the more interesting special fitments, in that it almost gained the status of a Mod, was Tornado GR.l STF248 covering provisions for NVGs. Implemented on some aircraft taking part in Desert Storm, STF248 was based on pioneering SAOEU work and involved placing light filters over essential instruments and the moving map display; replacing white cockpit floodlighting with green; and (the only daylight-visible change) altering the central warning lights panel to have red or yellow words on black backgrounds, instead of vice versa.

SAOEU has been working on NVGs since the Autumn of 1985 and is near to completing an exhaustive trial, having flown all types of Tornado GR. 1 mission except gun firing and medium-level bombing. As originally planned, a second-generation NVG system was to have been a ‘war only’ fit in the Tornado’s front cockpit, but by 1987 it had been decided to modify both cockpits with third-generation equipment.

Whereas the former is effective with ambient lighting down to a quarter-moon at least 30° above the horizon, third-generation is a true starlight system. With filtering, it has the added advantage that the crew can see yellow and red warning lights and read both handheld and projected (moving) maps — which rely heavily on these colours. On clear nights, Tornado crew with vision enhancement can dispense with the terrain-following and navigation radars and so deprive enemy listening equipment of a means of detecting their approach. Harrier pilots, on the other hand, can now fly when the aircraft would have been grounded by darkness.

S/L Bruce Chappie, who has been closely involved with NVG trials, explains that the new system involves filtering both the cockpit lighting and the crew’s NVGs. As a result, the light given off by the instrument panel is on a different wavelength to that which the goggles can receive, and therefore it will not interfere with the image intensifiers. Using the NVGs to see outside the cockpit, the crew glance under their goggles for a direct view of instruments. Several types of night vision goggles are on the market, but after evaluation of the GEC Cat’s Eyes system, the RAF opted for the ITT Defense AN/AVS-6 ANVIS, as issued to the US armed forces. Although looking like binoculars, night vision goggles would be incorrectly described as such because they provide two separate pictures and not true inocular vision. They weigh a not inconsiderable 2lb, so can be tiring on the neck muscles, and are most definitely not recommended when ejecting.

NVGs are unable to give a good view directly ahead of an aircraft travelling at speed, so they are complemented in this direction on the Harrier GR.7 and Tornado GR.4 by FUR. A three-week exercise in 1990 involved Tornadoes operating from an unlit West Freugh during nights so dark that it was quite easy for ground crew to sustain minor injuries through walking into parked aircraft.

Passive sensors — of which night vision systems were merely the first — will play an increasingly important role in the RAF of the mid-1990s. On the horizon is the terrain profile matching system of ‘stealthy’ navigation which will make the Tornado GR.4 even harder to detect. And, most certainly, there are other devices from which the dark wrap of security has yet to be pulled.

The Air Staff must be made aware of the capabilities of such equipment if it is to make realistic planning for its use in combat; squadrons must know how to get the most out of their new kit as it arrives. When the first Harrier GR.7 squadron becomes operational and the Tornado GR.4 takes the line, during a lull in the press interviews and speeches marking those events it might be possible to hear a representative of SAOEU saying quietly, «Remember, you saw it here first.’

’A&AEE (or ‘A2E2’) was until recently known as the AEROPLANE & Armament EXPERIMENTAL Establishment.

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