After several years of speculation, Singapore's defence ministry has at last confirmed that it is buying four Gulfstream G550 business jets modified with airborne early warning equipment to replace its Northrop Grumman E-2C Hawkeye aircraft.

Confirming the purchase last week, defence minister Teo Chee Hean said: "Equipped with a better radar and modern information systems, the G550 will significantly enhance the Republic of Singapore Air Force's airborne early warning and surveillance capability."

The defence ministry says the first aircraft, which can fly for 9h and operate at an altitude of 41,000ft (12,500m), will arrive by late 2008, with all four to be in service by 2010. Further details of the AEW system configuration and programme costs have not been disclosed, although industry sources say the aircraft are likely to be in a similar configuration to those now being delivered to the Israeli air force.

Gulfstream delivered Israel's first of four G550-based AEW aircraft last September, with Israel Aerospace Industries' Elta Systems subsidiary installing the aircraft's Phalcon-derivative phased array radar, which can also be used to detect ballistic missile launches using pod-mounted sensors. Israel has also now received two of the three G550 electronic intelligence aircraft acquired in the same deal.

Elta says its conformal AEW system for the Gulfstream includes two radar systems that operate simultaneously in different frequency bands, providing a 360° detection capability, plus advanced signal processors and a sophisticated communications suite. The aircraft's high-altitude flight profile ensures the long-range detection of low-flying targets, it adds.

To accommodate the mission system, Gulfstream increased the G550's maximum zero fuel weight by using a mid-wing fuel ejector that redistributes fuel from the inboard section of the wing to the outboard fuel cells, reducing wing loads at the fuselage. It also installed an extra generator on each of the aircraft's two Rolls-Royce BR710 engines, providing three times the electrical power of a standard G550 business jet.

Singapore's air force currently flies four E-2Cs delivered from 1985-6, according to Flight's MiliCAS database.

Source: Flight International