PAUL LEWIS /WASHINGTON DC

Among the targets are Singapore - which plans to replace F-5s - and the USAF

Raytheon is studying several solutions to equip the Boeing F-15E with an active electronically scanned array (AESA) for international fighter competitions. Singapore is the most immediate opportunity, while the US Air Force could be offered an upgrade for its F-15Cs and F-15Es.

"Boeing will offer an AESA radar on the F-15 for Singapore. The Raytheon radar will be based on APG-79 technology with AESA subsystems at the forward end and APG-63(V)1 hardware at the back end," says Raytheon. Singapore is expected shortly to launch a competition to replace its Northrop F-5S/Ts, with a version of the F-15E a candidate.

The APG-63(V)3 is based on the planned APG-79 AESA radar for the Boeing F/A-18E/F Super Hornet, but would incorporate improvements, which could include a scaled-up 0.9m (36in)- diameter array to take advantage of the F-15's larger nose volume, and tile transmit/receive module (TRM) technologies offering an improved mean time between overhaul over the current brick TRMs.

The APG-63(V)3 is unfunded because South Korea opted to equip 40 F-15Ks on order with the mechanically steered APG-63(V)1 to maintain commonality with the USAF's F-15Cs, but a joint programme, possibly with Singapore, is not ruled out. "Although funding for an AESA upgrade has not been identified, the development of the hardware building block has largely been paid for by the APG-79 radar programme," says Erv Grau, director USAF programmes, Raytheon Space and Airborne Sensors.

The USAF has asked Boeing to consider options for an F-15E mid-life upgrade starting in 2004, including provision for an AESA radar. The F-15Es are the USAF's newest version, first delivered in 1987, but they retain the APG-70. The olderF-15Cs are receiving the APG-63(V)1, which offers improved reliability, expanded memory and processing, and which can be upgraded with the APG-79's AESA.

More than 200 F-15Es are expected to remain in USAF service to at least 2030, while around 180 F-15Cs will be retained until 2020 to supplement the Lockheed Martin/Boeing F/A-22 Raptor. Raytheon has upgraded 18 Elmendorf AFB, Alaska-based F-15Cs with the APG-63(V)2, which has an AESA antenna, but the USAF is unlikely to fund any more and will instead jump to a modern radar such as the (V)3.

Source: Flight International