THAILAND'S STUDY of a second-phase avionics and structural upgrade of its fleet of 36 Northrop Grumman F-5E/F Tiger II fighters is attracting strong international interest.

The Royal Thai Air Force (RTAF) is understood to be holding initial discussions with several competing integrators, system vendors and airframe companies as it moves to extend further the F-5's operational life and capabilities.

Proposed work would include the installation of a new multi-mode pulse-Doppler radar, as a replacement for the F-5's outdated Emerson APG-159 system, and a structural life-extension programme. A decision on whether to proceed with the programme is expected by the end of the year.

A series of different options is under review, including Northrop Grumman's Tiger IV programme with the Westinghouse APG-66 radar, the Elbit/Singapore Aerospace Technologies' (STAe) Fiar Grifo F retrofit, the Lockheed Martin APG-67 and Israel Aircraft Industries Elta 2034 radar.

A new radar and structural life-extension programme would complement an earlier avionics upgrade overseen by the US Air Force. The programme included fitting a new GEC-Marconi head-up display (HUD), Litton LN-39 inertial-navigation system (INS) and mission computer. The RTAF has established a committee to study a proposed phase-two upgrade, but no funding has been allocated. Sources suggest that the proposal is gaining support as it is seen as a more-affordable alternative to purchasing new aircraft.

Thailand's military is being pressed to reduce expenditure to help combat the country's growing fiscal deficits. The RTAF's planned purchase of a second batch of eight McDonnell Douglas F-18C/Ds is now in danger of being dropped from the 1997 defence budget.

Indonesia, in the meantime, is also beginning to look at a possible follow-on upgrade programme for its 12 F-5E/Fs. The air force would like to fit a new multi-mode radar, but lacked sufficient funds to include it in the avionics programme awarded to Sabca.

Two test aircraft, an F-5E and tandem-seat F-5F, are already being modified in Belgium. The first upgraded fighter is scheduled to be rolled out in April 1997 and to be flown in August. The remaining seven F-5Es and three Fs will be modified locally at Mediun AB by 1997, using kits supplied by Sabca.

Changes include fitting a GEC-Marconi HUD, Litton LN-93 INS, central data unit, Vinten camera and rear-cockpit monitor. Plans to fit the Indonesian F-5s with GEC's Sky Guardian Radar warning receiver have been dropped in favour of the Litton ALR-91

Source: Flight International