With the recent retirement of the FB-111, the F-15E has become the USAF's premier deep strike/inter-diction aircraft. While the USAF's new F-22 will be able to carry A/G ordnance internally and externally, the F-15E will still continue to serve as the principle A/G weapons delivery platform until a new design is approved.

The heart of the F-15E's electronics suite is the AN/APG-70 radar. It is intended to be used without being detected by an enemy's air defenses. The radar has an LPI (low probability of intercept) mode that allows a rapid single-sweep synthetic aperture radar image of a target area located as much as 45 degrees to either side of the aircraft's flight path, then the radar is switched off seconds later, making it difficult for an enemy to pick up the emissions and track the F-15E's location and flight path. The radar map can be "frozen" on the screen, and updated periodically by new sweeps as the aircraft gets nearer to the target, also allowing for stealth operation.

The radar display terminals process the radar signals received and can provide a bird's eye view of ground targets that are of higher resolution and taken from further away than the images produced by previous radars. Roads, bridges, and airfields can be identified as far as 100 miles away, and as the F-15E nears the target image resolution becomes progressively sharper and smaller targets such as trucks, aircraft, and tanks can be distinguished.

APQ-70

The APQ-70 is an improved version of the APQ-63 attack radar designed for the F-15E. The system has improved software and hardware, with all hardware conforming to MIL-STD-1750A architecture. The -70 also has growth provisions for increased memory capacity, processing speed, and mode enhancements. A2G modes include precision velocity update and A2G ranging. It permits the crew, flying at a low altitude, to pick out targets from distances of 73nm.

The -70 A2G weapons delivery and high resolution mapping modes can only be accessed by those F-15C/D F-15E a/c with dual-role mode capability. The system uses a synthetic aperature radar (SAR) imagery for better resolution in the real-beam ground mapping modes. The original resolution specification of 8.5' resolution at 20nm was met and may have been exceeded. The -70's search modes in the A2A role are RWS (range while scan) and velocity search. Three RWS modes use high, medium, or interleaved PRF. The APG-70's TWS mode is accessed once targets are sorted. Other modes in the A2A role are single target track, raid-assessment track, vertical search, super search, boresight, and auto-gun target acquisition modes.

Variants:

APQ-80 is a modified -70 for use in the AC-130 Spectre gunship. Five additional operation modes: fixed target track, ground moving target indicaction and tracking, projectile impact point position, beacon track, and weather mode for firing in poor visibility. Upgrades also include a digital scan converter and modifications of the -70's signal processor and antenna.

Combat Experience:

During DS the -70 proved as effective as had been hoped, with many observers calling the F-15E/APG-70 combination the best strike a/c in the world. As an A2G radar, it's resolution over long range was said to be excellent. The radar was also reported to be very reliable.

APG-73 The APG-73 is a US/Canadian program to greatly improve the F/A-18 Hornet's APG-65 radar by retaining the transmitter and antenna, but updating the receiver/exciter and developing new components that replace the general purpose radar data processor (RDP) and digital programmable signal processor (PSP). Better resolution, added modes, and better ECCM are some of the benefits. Processing speed and power increases are considerable. The PSP's speed jumps from 7.1 million complex operations per sec to 60 million; spare capacity allows a later increase to 80 million. Memory capcity expands to one megaword in the PSP and two megawords in the RDP. RDP speed increases to 2 million instructions per sec. A/D converters also speed up several times. A later phase upgrades synthetic aperture radar mode processing and a motion sensor subsystem that counteracts distortions from airframe bending that degrade accuracy in the current inertial system. A third phase would introduce the active array antenna. All F/A-18's built for the Navy after 1989 have the APG-73 as well as several foreign customers.

Another key element of the F-15E's weapons delivery system is the LANTIRN (which is an acronym standing for Low-Altitude Navigation and Targeting, Infra-Red for Night) system, which consists of two pods, one carried underneath each air intake. The starboard pod is used for navigation and contains a FLIR (Forward-Looking, Infra-Red) which can be used to display a high-quality video image of the oncoming terrain on the pilot's heads-up display, enabling high-speed low-level flights to be made at night under clear weather conditions.

The navigation pod also carries a terrain-following radar which is also effective in bad weather. The pilot can manually respond to cues from the system or can couple the system to the flight controls for "hands-off" automatic terrain-following flight at altitudes as low as 200 feet off the deck. The port pod is a targeting pod which contains a high-resolution tracking FLIR, a missile boresight correlator, and a laser designator. The boresight correlator is used to guide the Maverick air-to-surface missile and the laser designator is used for weapons such as laser guided bombs that home in on reflected laser light.

Front and rear cockpits are upgraded with multi-purpose cathode ray tube displays for improved navigation, weapons delivery, and systems operations. The pilot's cockpit has redesigned controls, a wide field of vision heads-up display, and three cathode ray tubes which provide multi-purpose displays of navigation, weapons delivery, and systems operations. The rear-cockpit weapons system officer has four cathode ray terminals for radar, weapons selection, and monitoring of enemy tracking systems.

The WSO has at his disposal an updated ALQ-135 electronic warfare system which features a new broadband jammer. The antennae for this system are located at the trailing edge root of the left horizontal atablizer and in the leading edge roots of both wings. This replaces the blade antennae located under the nose of the A, B, C, and C versions.

Multi-Stage Improvement Program for F-15

The Multi-Stage Improvement Program (MSIP) is a joint program carried out by McDonnell Douglas and the USAF's Warner Robins Logistics Center in Georgia. Under MSIP, upgrades were progressively incorporated onto the production line and then retrofitted to earlier production F-15Cs.

It is planned that almost all F-15A, B, C, and D versions are to go through the program. The analog computers of the F-15A/B will be replaced by digital computers, and the digital computers of the F-15C/D will be replaced by more advanced digital computers. The weapons panel will be improved, and a cathode ray terminal similar to that found on the F-15E will be fitted. The F-15C/D will be fitted with chaff/flare dispensers behind the nosewheel door. The A models that go through the MSIP will not be fitted with the conformal fuel tanks of the C, but they will be otherwise indistinguishable. However, some of the very early As (from FY 1973, 1974, and 1975) will not be upgraded under MSIP but will rather be retired and made available as gate guards or donated to museums. Some of them will be given to Israel as payment for policy decisions made during the Gulf War.

Under the Multi-Stage Improvement Program (MSIP), upgrades were progressively incorporated onto the F-15C production line and then retrofitted to earlier production F-15Cs. One of these improvements involved a significant improvement of the capabilities of the APG-63 radar fire control system. The memory capability of the APG-63 radar fire control system was increased from 96K to 1000K and the processing speed was trebled. A Programmable Armament Control Set (PACS) was installed. The Electronic Warfare Warning Set (EWWS) was modified into the more capable Tactical Electronic Warfare System (TEWS) equipped with an upgraded ALR-56C radar warning receiver and an ALQ-135 electronic countermeasures set. An overload warning system was provided to prevent pilots from accidentally exceeding 9g during combat maneuvering.

Furthermore, the aircraft were fitted with the wiring needed to give them the capability of carrying and launching the AIM-120 AMRAAM missile, which was introduced into service on the F-15C in the early 1990s. Another part of the MSIP was the Seek Talk program, which was designed to reduce the vulnerability of the UHF radios to enemy jamming by introducing spread spectrum techniques and the use of a null steering antenna. Yet another was the Joint Tactical Information Distribution System (JTIDS), which is intended to provide a high-capacity, reliable, and jam-proof information link between various elements of deployed forces and command and control centers. Included with this program is the integration of the F-15 with the Global Positioning Satellite (GPS).

Later upgrades took place under the aegis of MSIP II. MSIP II involved the development of a new radar, the Hughes AN/APG-70. In this unit, the radar data processor memory was increased from 16K to 24K, and its processing speed was increased by a factor of three. The new unit has multiple bandwidths for high-resolution ground mapping using Synthetic Aperture Radar (SAR) technology. The radar can produce photo-realistic patch maps of a given area down to the 8.5 foot (2.6 m) resolution at 10 nautical miles from the target. Resolution diminishes to a maximum of 127 feet (38.7 m) at 160 nautical miles. The first aircraft to go through MSIP II was F-15C 84-0001, first flown on June 20, 1985.

The F-15 carries a classified electronics warfare package known as the Tactical Electronic Warfare System (TEWS). Defensive avionics include the Northrop ALQ-135(V) internal countermeasures system, which acts on information from the Loral ALR-56C and Magnavox ALQ-128 radar warning suites and provides active jamming against enemy radar threats. The Loral ALR-56 radar warning receiver (RWR) system has external antennae mounted on each fin tip and on both wingtips. A fifth blade-shaped antenna is mounted underneath the forward fuselage. The all solid state ALR-56 is based on a digitally-controlled dual channel receiver that scans from 6-20 GHz, while changes in the perceived threat can be accommodated by changing the software. Tracor ALE-45 chaff/flare dispensers are provided.

Following completion of operational test and evaluation at Edwards AFB and weapons carriage and separation tests carried out at Elgin AFB, F-15Es were first delivered to the 425th TFTS, 405th TTW at Luke AFB for crew training. The first operational F-15E squadron was the 336th TFS, 4th TFW at Semour Johnson AFB in North Carolina, which received its first planes in early 1989. Limited operational capability was obtained with the F-15E in October 1989, with full operational capability being projected for August 1990.

F15 Eagle in Desert Storm

On August 1, 1990, Iraqi forces invaded Kuwait. On August 6, the US launched Operation Desert Shield to defend against any Iraqi moves southward against Saudi Arabia. The 1st Tactical Fighter Wing based at Langley AFB began deployment of its F-15C/Ds to Dhahran in Saudi Arabia. On August 12, F-15Es from the 336th TFS of the 4th TFW based at Semour Johnson AFB left for the Gulf. The F-15E Strike Eagle was still not not completely ready for combat, since it did not yet have the targeting pod of its LANTIRN system installed.

The F-15C/Ds began to fly combat air patrols in cooperation with Saudi F-15Cs and British and Saudi Tornado F.Mk 3s, whereas the F-15Es began to train for the strike mission should that become necessary. During such a training mission, F-15E serial number 87-0203 crashed on September 30, 1990, killing both crewmen.

A second round of Desert Shield buildups took place in November of 1990. The 33rd TFW deployed its 58th TFS, equipped with F-15C Eagles, to Tabuk in western Saudi Arabia. The 53rd TFS of the 36th TFW based at Bitburg in Germany also deployed to Tabuk. Aircraft of the 525th TFS joined the 7440th Composite Wing based at Incirlik in Turkey. the 32nd TFS based at Soesterberg in the Netherlands also deployed to Incirlik. A second F-15E squadron, the 335th from the 4th TFW, moved to Al Kharj.

Operation Desert Storm began on the morning of January 17, 1991. Most of the air-to-air engagements during the war were fought by the F-15C, and most of these by pilots of the 58th TFS. 36 enemy aircraft were destroyed by USAF F-15Cs during the Gulf War, against zero losses. Many of the kills were against Iraqi aircraft caught by chance or attempting to flee to Iran. There was relatively little of the dogfighting at which the F-15 had been built to excel--most of the kills were made at BVR range by the AIM-7 Sparrow missile, which had performed so poorly in Vietnam but which turned in an outstanding performance in the Gulf War.

Nine kills were made by the F-15C with the AIM-9 Sidewinder missile, and one kill was credited to a F-15C pilot who maneuvered his MiG-29 opponent into flying his aircraft into the ground. The F-15C's 20-mm cannon was never fired in anger during Desert Storm. In addition, the AIM-120 AMRAAM missile was not fired in anger during the war, although there were more than 1000 "captive carries" of the missile during combat missions in the last few days of the war.

One F-15C (85-0102) scored three aerial victories during Desert Storm, although not all scored by the same pilot on all three occasions. Two F-15C pilots are credited with three aerial victories apiece, although one of each pilot's victories occurred on March 22, 1991, after the war was officially over.

Although the F-15E Strike Eagle was still not fully combat-ready, 48 F-15Es flew in the Gulf War. F-15Es joined other Coalition aircraft in searching for and attacking Iraqi "Scud" missile launchers. These Scud hunt missions were largely unsuccessful, but the F-15Es attacked many other Iraqi targets of opportunity. Most of these sorties were flown at medium altitudes, and the F-15E did not get much of a chance to demonstrate its low-level capabilities.

Although only some of the F-15Es were equipped with their LANTIRN targeting pods by the end of the Gulf War, pilots claimed that 80 percent of the laser-guided bombs dropped by F-15Es hit their targets. However, difficulties were still being encountered in fully integrating the LANTIRN system with the F-15E. The commitment of the targeting pod to battle seems to have been premature, and the system was not employed in combat to its full capacities.

No F-15C/D Eagles were lost in combat, although two F-15E Strike Eagles were shot down by ground fire, one on Jan 18 (88-1689) and the other on Jan 19 (88-1692). The crew of the first plane were killed, the crew of the second were taken prisoner.

F-15 victories during the Gulf War include numerous MiG 29s, MiG 25s, MiG 23s, Su 22s and a few helicopters. In addition, a two-seat F-15E scored a kill by dropping a laser-guided bomb on an airborne Iraqi helicopter on February 14.

After the war was officially over, F-15Cs continued to carry out combat air patrols, enforcing the "no-fly" restrictions on Iraqi fixed-wing aircraft imposed under the terms of the cease-fire. On March 22, F-15C 84-0014 flown by Capt John T. Donski of the 22nd TFS shot down one of two Iraqi Su-22s with an AIM-9 missile, the other Su-22 making a hasty landing. On March 24, F-15C 84-0010 flown by Capt Thomas N. Dietz of the 53rd TFS shot down another Su-22 violating the no-fly order. This was Capt Dietz's third kill, he having taken a pair of MiG-21s on February 6. The pilot of another F-15C, Lt Robert Hehemann was able to claim a Pilatus PC-9 trainer which was flying in close vicinity of the downed Su-22 when its pilot baled out without a shot being fired. This was kill number three for Lt Hehemann as well.

F-15 Wild Weasel

In 1994, the USAF awarded a contract to McDonnell Douglas to explore the feasibility of adapting the F-15C to the Suppression of Enemy Air Defenses (SEAD) role --- the so-called Wild Weasel mission currently performed by the two-seat F-4G Phantom II. As part of the program, it is proposed that eight F-15C aircraft be converted to fire the AGM-88 HARM antiradiation missile. Additional avionics for the SEAD role would be provided in distinctive "cheek" fairings.

If the eight aircraft in the proposal are actually funded, Initial Operational Capability (IOC) should occur in August of 2000. However, the Air Force is skeptical about the feasiblity of a modified F-15C for the Wild Weasel mission, preferring a two-seat aircraft for this role. The aircraft that the USAF would REALLY like to have for the Wild Weasel role is a modified two-seat F-15E, but this is considered much too expensive an option in the current military drawdown environment. The USAF is also considering an adaptation of the F-16 for the Wild Weasel mission, in light of Israeli success in using specially-adapted two-seat F-16s for air defense suppression missions.

Recently the Block 40 F16 with its LANTIRN package has performed very well in New Mexico under the Air National Guard. The role of the 150th TFS "Tacos" is Night Attack. In a wartime scenario the F-16s would likely carry GBU-10s and GBU-12s along with AGM-65D Mavericks. A new task, known as "Killer Scout," extends the all-weather capability of the F-16 to precissely navigate, acquire, identify and kill targets. An intergrated INS/GPS with imbedded digital terrain (TERPROM) referencing allows the Killer Scout to not only know the aircraft's exact position but also to consistently roll-in on the target and have the aim-point within two to ten meters of the exact grid reference.

Eagles In Israel

The first 2 F-15I's have been delivered this week. The aircraft will not be carrying sidewinders, you forget that Israel has one of the best IR AAM's in the world called Python 4. Python 4 is a FOURTH generation IR missile made by Rafael and won first prize at the Paris Air Show in 1997. Following is information from the Air Show and Rafael.

Fourth Generation A/A missile made by Rafael

Main Features:

• In operational use in the Israeli Air Force
• Revolutionary no escape volume
• Unique aerodynamic configuration for superior agility
• State-of-the-art, high performance seeker
• Advanced IRCM & background rejection capabilities
• Highly effective fragmentation warhead

News Article from the Paris Air Show, June, 1997

In 1996, Israel finally unveiled the latest addition its air-to-air combat armory, the Rafael Python-4 Although speculation about the existence of the weapon had been widespread, official confirmation of its existence and capabilities caused a stir all over the world.

Rafael stresses that the new short-range missile is not simply an extension to its range of Shafrir and Python products, but a step advance to a true fourth-generation infra-red-guided look-and-shoot missile.

Its primary advance it to expand the "no-escape" zone within which an enemy aircraft has no hope of evading the missile. with an increased velocity and high offboresight capability, the Python-4 enlarges the no-escape volume dramatically to almost any frontal target. In short, any aircraft in the pilot’s forward field of vision within range will be destroyed regardless of its flightpath or of any evasive maneuver it makes up to 9G.

To achieve this, the Python-4 not only needs the power and aerodynamics to make fast turns, but also requires special-pursuit trajectory algorithms. For example, the missile may cut across the path of an evading aircraft to pursue it through a high-g turn. Previous missiles would simply have lost the target. Such trajectories - and from a wide range of angles.

Rafael adds that the Python-4 is not a development project but a mature weapon system. As the Israeli defense ministry revealed in 1996, and operational with the Israeli air force.

For more on the F15 go to Part 1

Other Sources:

• Dennis R. Jenkins
  McDonnell Douglas F-15A/B/C/D/E Eagle/Strike Eagle (Aerofax Datagraph 6)

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