Douglas Barrie/LONDON

THE UK MINISTRY of Defence (MoD) is expected to give the go-ahead in September for the feasibility study for the Royal Air Force's future offensive aircraft (FOA).

A "mini-B2" design has been ruled out, but a stealthy development of the Eurofighter EF2000 will be considered.

The MoD's Equipment Approvals Committee will consider the feasibility study for the FOA in September. The study is intended to allow the RAF to "-identify a preferred concept by 1999". This may be followed by a flying demonstrator programme, unofficially dubbed EAP Mk2 within some MoD circles.

Alongside the EF2000, the FOA, or Staff Requirement (Air) 425, is a crucial project for the RAF. The outcome of the feasibility study will influence whether the RAF pursues the US Joint Strike Fighter (JSF) programme, and whether it retains an advanced short take-off and vertical-landing capability beyond the British Aerospace Harrier GR7.

In turn, this feasibility will affect which service is tasked with providing close air support, according to RAF officials.

While the Royal Navy is committed to the US/UK Joint Strike Fighter (JSF) concept as providing the follow-on aircraft to the British Aerospace Sea Harrier F/A2, the RAF doubts that whatever emerges as the JSF will meet its FOA requirement.

The FOA is intended to replace the Panavia Tornado GR4/4A strike aircraft from 2015, with pre-feasibility studies running from 1993 to the end of 1995.

These focused on several "aircraft-based weapon-system concepts" covering single- and twin- engined aircraft configurations with one or two crew.

Artists impressions of designs show aircraft exhibiting similarities to the US Air Force's Boeing/Lockheed Martin F-22 and the JSF, as well as several more radical plan forms.

BAe has also submitted a big-wing variant of the EF2000 as a potential FOA candidate. MoD officials say that if the EF2000 was to form the basis of the FOA airframe, then further substantial changes would be needed, included improving its low-observable characteristics.

The pre-feasibility stage covered designs optimised to varying degrees for low observability. The MoD will not discuss in detail its "stealth" projects, but its High Agility Low Observable (HALO) programme with BAe is understood to be such a project.

The results of the HALO programme, which may cover sub-scale prototype shapes, would feed into the EAP Mk2 if the demonstrator platform route is pursued.

MoD officials say that pilotless combat aircraft will also be considered, as will using a "non-penetrating large aircraft", fitted with cruise-missile rotary launchers.

The latter could mean using a common airframe, possibly the eventual replacement for the Vickers VC10 and Lockheed L-1011 TriStar .

This solution is not favoured by the RAF because it falls far short of meeting many of the roles it wants the FOA to fulfil. These cover: air interdiction, offensive counter air, tactical air reconnaissance, suppression of enemy air defences, anti-surface warfare, and offensive air support.

The aircraft should be capable of internally carrying two 900kg-class weapons and two self-defence air-to-air missiles (AAMs) or four 900kg-class weapons and two AAMs externally.

Internal carriage would only be required if a low-observable design is preferred.

The RAF's favoured FOA configuration would appear to remain a twin-engined, two-crew aircraft, although officials maintain that this remains an open issue.

A two-crew cockpit is viewed as providing a "lowest-risk route", whereas an uncrewed combat aircraft is considered as a high-risk approach.

Officials have raised concerns over whether the technology for a crewless platform would be "sufficiently mature" within the required time scale.

Off-the-shelf, national and collaborative projects will be examined. US/UK and European collaborative projects could possibly provide a platform to meet the FOA requirement.

Source: Flight International