Raytheon to equip F-15Es with new radar systems

 - November 11, 2007, 6:46 PM

Raytheon has won a competition to provide new radars for the U.S. Air Force’s entire fleet of Boeing F-15E Strike Eagles, maintaining its position as sole provider of radars for the Eagle family. Along with a radar replacement program for the F-15C fighter, foreign sales and ongoing sensor production for the Boeing Super Hornet, the new deal means that Raytheon’s potential order book for active-array fighter radars now stands at over 900 units.

The F-15E currently uses Raytheon’s APG-70 radar–in its day a revolutionary sensor, but it has remained largely untouched since its development in the 1980s. To update the F-15E, the U.S. Air Force opened an F-15E Radar Modernization Program (RMP) and partnered with Boeing to run a competition for a new sensor. Following bid submissions from Raytheon and Northrop Grumman, the former landed a source selection award (SSA) on November 1. Along with the technical bid, Raytheon submitted a number of procurement rate and spares supply level options to meet variable budgetary and delivery rate requirements.

Boeing selected Raytheon in anticipation of the Air Force’s F-15E RMP system design and development contract (SDD), expected in June next year. Raytheon will also provide test assets under the terms of the SSA. Its radar for the RMP is already undergoing airborne tests in a company-owned aircraft. The SDD phase is expected to run through 2009/10, with production starting in 2011.

The RMP radar represents the latest in a “spiral” development of active electronically scanned antenna (AESA) technology. Raytheon fielded the first fighter AESA in the form of the APG-63(V)2 radar fitted to 18 F-15Cs in Alaska. The company lost its bid to provide the radar for the JSF, but the effort nevertheless provided the “tile” technology that resulted in the APG-79 for the Super Hornet.

The F-15E RMP sensor represents a continuation of that technology. It will be an entirely new sensor, with new “back-end” processors and power supplies, as well as the active array. Not only will the sensor provide much better air-to-air and air-to-ground capabilities, but also electronic warfare and communications functions.
In a demonstration of the latter, Raytheon transferred an 8 Mb file through the antenna in 80 milliseconds–a data transfer rate of 274 Mb per second. Furthermore, with no moving parts the new array requires virtually no maintenance for the life of the aircraft. The multi-tile nature of the array means that the malfunction of one or more tiles will not affect the array’s performance to any degree until large numbers are not working.

Fighter Eagle Kit

Apart from the F-15E RMP, Raytheon provides new radars for the F-15C fighter fleet. Ultimately, the U.S. Air Force plans to upgrade 226 F-15C/Ds with the APG-63(V)3 radar. This sensor retains most of the back-end of the existing APG-63(V)1 radar, but replaces the mechanically-scanned antenna with an active array based on that of the APG-79 used in the Super Hornet. The F-15C upgrade is split between the Air National Guard and active-duty Air Force. The ANG program calls for half of its long-term fighter Eagle fleet to be equipped with the AESA radar, for a total of 48 units. The first contract for six upgrades was let in 2006, while the Fiscal Year 2007 contract is currently being finalized for six to eight units. The first ANG aircraft will be flying in 2009. A minimum of six per year is to be procured until the total is achieved. The 48 remaining ANG F-15s will retain the mechanically-scanned radar, but through datalinks it can receive targeting data from the AESA-equipped machines.

Meanwhile, in FY07 the active-duty Air Force allocated the first funding for APG-63(V)3 installation in its long-term F-15C/D fleet. The first contract is being finalized for six to eight upgrades, out of a planned total of 178. The APG-63(V)3 has been tested in a trials aircraft at Eglin AFB, Florida.

Raytheon is also supplying APG-63(V)3 radars for the F-15s headed for Singapore and the Republic of Korea. Other Eagle operators have also shown interest in AESA radars—Saudi Arabia has requested information on active arrays via the U.S.
government. Raytheon’s other principal AESA business, which furnishes APG-79s for the U.S. Navy’s Super Hornets,  has just received a boost with a go-ahead to produce 135 radars to retrofit the early production aircraft initially fitted with the mech-scan APG-73. This runs alongside radar production for new-build aircraft.   

Eagles grounded

A fleet-wide F-15 grounding order by the U.S. Air Force followed the crash of a Missouri Air National Guard Boeing F-15C Eagle on November 2. The order covered all 676 F-15s, including those on deployed operations. However, a spokesman said that they could be made available for operations in an emergency.

F-16s and other types have taken their place while the Eagles remain on the ground. An F-15E was due to participate in the air show here.

The Eagle from the 131st Fighter Wing was one of four flying from St Louis-Lambert Field on a training sortie when it crashed in Dent County, Missouri. The pilot ejected safely, incurring minor injuries. While a full investigation is under way, preliminary findings point to a structural failure that caused the fighter to break up in mid-air.
Both the Israeli Air and Space Force and Japan Air Self Defense Force have grounded their Eagles, although Japan’s F-15Js remain on air defense alert. Japan’s Mitsubishi F-2s are also grounded following a crash on October 31, leaving the JASDF with the elderly F-4EJ as its only operational fighter type. 

More F-15s for Singapore

On October 22, Boeing announced that the Republic of Singapore air force had exercised its existing option to purchase eight F-15SG multi-role fighters. The options were covered in the original order for 12 Eagles. Additionally, the RSAF added four more Eagles, raising its total buy to 24.