A multi-stage improvement program for the E-3 began with a U.S. Air Force award of the ICON (Integration Contract) to Boeing in May 1987. ICON will equip both U.S. and NATO E-3s with an electronic support measures (ESM) passive surveillance capability, and other enhancements to the U.S. E-3 fleet.

The latter improvements for the U.S. fleet include:

• Upgrading the Joint Tactical Information Distribution System (JTIDS) to TADIL-J (Tactical Digital Information Link-J);
• Increasing computer capacity; and
• The ability to use the Global Positioning Satellite system to pinpoint AWACS' location anywhere in the world.

Development of these enhancements was completed in 1994. Also in 1994, Boeing received contracts from NATO and the U.S. Air Force, worth $16.8 million and $127 million, respectively, to produce ESM kits for their E-3 aircraft. The most significant upgrade yet developed for the E-3, ESM was developed by Boeing under joint funding from the U.S. Air Force and NATO under the ICON contract.

ESM is a passive listening and detection system, which enables the AWACS to detect, identify and track electronic transmissions from ground, airborne and maritime sources. Using the ESM system, mission operators can determine radar and weapon system type. In October 1995, the first U.S. E-3 aircraft was equipped with ESM. USAF personnel at Tinker Air Force Base, Okla., will install the remaining ESM kits on U.S. aircraft during scheduled depot maintenance.

In March 1989, Boeing was authorized to begin production of Have Quick A-NETS, an improved communication system that provides secure, anti-jam radio contact with other AWACS, friendly aircraft and ground stations to a degree not previously available. Retrofit of the U.S. fleet was completed in late 1994.

Also in 1989, Boeing began full-scale development of an upgrade to the AWACS radar (APY1,2), called the Radar System Improvement Program (RSIP), a multinational cooperative effort. RSIP will improve the E-3ís radar by increasing the sensitivity of the pulse Doppler radar so the aircraft can detect and track smaller stealthy targets over a long range. It also will improve the radarís counter-countermeasures capability (making it harder to jam the system), upgrade the radar operatorís console, replace the radarís existing computer with a new high-reliability multiprocessor and rewrite the radar software to make it easier to maintain and enhance in the future.

Development and flight testing was completed with NATO joining the program in 1994 and the U.S. and NATO conducting developmental flight testing and operational assessments of the radar improvements. Limited production was approved in late 1996, with full production authorized in late 1997. The United Kingdom joined the program in 1996.

Production of 18 kits for NATO, eight kits for the United Kingdom and six kits for the U.S. Air Force has begun. Kit deliveries began in 1998 and will continue until 2002. The U.S. Air Force will install RSIP kits at Tinker Air Force Base during scheduled depot maintenance. The installation of NATO kits began in late 1997 at Daimler-Benz Aerospace in Germany, under contract to Boeing. Retrofit of all 17 NATO aircraft will be completed in 1999.

In October 1994, the U.S. Air Force Air Combat Command (ACC), in partnership with the Air Force's Electronic Systems Center (ESC), initiated Extend Sentry, a program to upgrade and extend the life of the U.S. E-3 AWACS fleet through the year 2025. Extend Sentry will help meet immediate Air Force sustainment needs, as well as future performance and mission requirements. Extend Sentry will address issues such as obsolete parts, increased maintenance, repair downtime and a shrinking supplier base.

In 1993, NATO's AWACS modernization program intensified. Throughout the year, Boeing delivered production-quality, upgraded computer systems to NATO as part of the Memory Upgrade Program. Under this effort, Boeing upgraded the existing IBM CC2 computer to the CC2E model.

In 1993, NATO also awarded three major upgrade contracts to Boeing. In January, the company received a $294.6 million procurement and production contract as part of the Mod Block 1 phase of NATO's modernization program. A $35.5 million follow-on contract to install and test Mod Block 1 hardware was received in May.

Mod Block 1 covers three important mission system-related enhancements:

• Color displays, which will improve the form and usability of incoming situational information;
• "Have Quick" radios, which will enhance UHF communications by adding antijam features; and
• A version of the Joint Tactical Information Distribution System (JTIDS), called Link 16, which will increase the amount of information that can be collected and distributed among other AWACS airplanes, allied aircraft and ground stations.

During 1996 and 1997, 17 NATO E-3 aircraft were retrofitted with Mod Block 1 equipment (including ESM) and returned to the operational fleet.

In November 1997, Boeing received a contract worth approximately $450 million to develop and test a mission systems upgrade for the NATO E-3 fleet. Under the engineering, manufacturing and development (EMD) contract, which runs through 2001, Boeing -- supported by subcontractors from participating NATO nations -- will integrate major system-related enhancements to computers, displays, communications, navigation and target identification. Retrofit of the entire fleet will be implemented during a follow-on contract.

Current and planned improvement programs will maintain E-3's status as the world's most advanced airborne early warning system into the next century.