The Royal Air Force is unlikely to receive its first upgraded Nimrod MR4 maritime patrol aircraft until 2002, as a result of delays to the £2 billion ($3.3 billion) modification programme.

The programme is thought to be up to eight months behind schedule, the first aircraft having been delivered for delivery in December 2001. "The Ministry of Defence was informed of the problem months ago - we are confident that we can deliver the aircraft on time despite the delay," says prime contractor British Aerospace.

The work, involving major structural renovation, new engines and a Tactical Command System supplied by Boeing, has been delayed "by a number of factors", according to BAe, which denies that problems with avionics integration are the major cause.

Progress on the airframe and engine modifications are on schedule, says FR Aviation, which is refurbishing the airframe, and Rolls-Royce, provider of the BMW-R-R BR710 turbofans.

Boeing, which has a $639 million contract for the tactical systems, has built an integration laboratory for the aircraft's tactical command systems and carried out the first operational software loading for the programme. The laboratory will be used to test the major sensors, including the radar, electronic support measures, electro-optical system, subsurface acoustics and defensive aids.

A 15-month integration test programme is about to begin, leading to formal qualification testing of the command and sensor system in mid-2000. The first flight is due in the third quarter of 2000.

The Nimrod was at the centre of a procurement debacle in the 1980s, when attempts to convert airframes to the airborne early warning role foundered over integration problems and spiralling cost overruns that led to the purchase of the Boeing E-3D.

Source: Flight International