F - 16 Fighting Falcon

The Lockheed Martin F-16 Fighting Falcon is a multirole jet fighter aircraft originally developed by General Dynamics for the United States Air Force. Designed as a lightweight, day-time Visual Flight Rules (VFR) fighter, it evolved into a successful multirole aircraft. The Falcon's versatility is a paramount reason it has proven a success on the export market, having been selected to serve in the air forces of 25 nations. The F-16 is the largest Western jet fighter program with over 4,400 aircraft built since production was approved in 1976. Though no longer being bought by the U.S. Air Force, advanced versions are still being built for export customers. In 1993, General Dynamics sold its aircraft manufacturing business to the Lockheed Corporation, which in turn became part of Lockheed Martin after a 1995 merger with Martin Marietta.

The Fighting Falcon is a dogfighter with numerous innovations including a frameless, bubble canopy for better visibility, side-mounted control stick to ease control while under high g-forces, and reclined seat to reduce the effect of g-forces on the pilot. The F-16 has an internal M61 Vulcan cannon and has 11 hardpoints for mounting various missiles, bombs and pods. It was also the first fighter aircraft deliberately built to sustain 9-g turns. It has a thrust-to-weight ratio greater than one, providing power to climb and accelerate vertically — if necessary. Although the F-16's official name is "Fighting Falcon", it is known to its pilots as the "Viper", due to it resembling a cobra snake and after the Battlestar Galactica starfighter. It is used by the Thunderbirds air demonstration team.

The F-16 is scheduled to remain in service with the U.S. Air Force until 2025. The planned replacement is the F-35 Lightning II, which is scheduled to enter service in 2011 and will gradually begin replacing a number of multirole aircraft among the air forces of the program's member nations.

Development

Origins

Real-world experience in the Vietnam War revealed some shortcomings in American fighter capabilities, and the need for better air-to-air training for fighter pilots. The need for new air superiority fighters led the USAF to initiate two concept development studies in 1965: the Fighter Experimental (FX) project originally envisioned a 60,000 lb (27,200 kg) class twin-engine design with a variable-geometry wing, and the Advanced Day Fighter (ADF), a lightweight design in the 25,000 lb (11,300 kg) class which would out-perform the MiG-21 by 25%. However, the first appearance of the Mach-3-capable MiG-25 'Foxbat' in July 1967 resulted in the ADF effort being deemphasized in favor of the FX program, which would produce the F-15, a 40,000 lb (18,100 kg) class aircraft.

Based on his experiences in the Korean War and as a fighter tactics instructor in the early 1960s Colonel John Boyd and mathematician Thomas Christie developed the Energy-Maneuverability (E-M) theory to model a fighter aircraft's performance in combat. Maneuverability was the key to a process Boyd called the "OODA Loop" (for "Observation-Orientation-Decision-Action"). Boyd's work called for a small, lightweight aircraft with an increased thrust-to-weight ratio. A 1965 Air Force study suggested equipping its squadrons with a mix of high and low cost fighters as being the most economical.

Lightweight Fighter program
In the late 1960s Boyd gathered around him a group of like-minded innovators that became known as the "Lightweight Fighter Mafia". In 1969, the "Fighter Mafia" was able to secure funds for a "Study to Validate the Integration of Advanced Energy-Maneuverability Theory with Trade-Off Analysis". General Dynamics received $149,000 and Northrop $100,000 to develop design concepts that embodied Boyd’s E-M theory – a small, low-drag, low-weight, pure fighter with no bomb racks; their work would lead to the YF-16 and YF-17, respectively.

Although the Air Force’s FX proponents remained hostile to the concept because they perceived it as a threat to the F-15 program, the ADF concept (revamped and renamed as the ‘F-XX’) gained civilian political support under the reform-minded Deputy Secretary of Defense David Packard, who favored the idea of competitive prototyping. As a result in May 1971, the Air Force Prototype Study Group was established, with Boyd a key member, and two of its six proposals would be funded, one being the Lightweight Fighter (LWF) proposal. The Request for Proposals issued 6 January 1972 called for a 20,000 lb (9,100 kg) class air-to-air day fighter with a good turn rate, acceleration and range, and optimized for combat at speeds of Mach 0.6–1.6 and altitudes of 30,000–40,000 ft (9,150–12,200 m). This was the region in which the USAF expected most future air combat to occur, based on studies of the Vietnam, Six-Day, and Indo-Pakistani wars. The anticipated average flyaway cost of a production version was $3 million. This production plan, though, was only notional as the USAF was under no obligation to acquire the aircraft and, in fact, had no firm plans to procure the winner, which was to be announced in May 1975.

Five companies responded and in March 1972, the Air Staff announced the winners for the follow-on prototype development and testing phase were Boeing’s Model 908-909 and General Dynamics’ Model 401; however, after further review, the Source Selection Authority (SSA) would demote Boeing’s entry to third place, after Northrop’s P-600. GD and Northrop were awarded contracts worth $37.9 million and $39.8 million to produce the YF-16 and YF-17, respectively, with first flights of both prototypes planned for early 1974. To overcome resistance in the Air Force hierarchy, the 'Fighter Mafia' and other LWF proponents successfully advocated the idea of complementary fighters in a high-cost/low-cost force mix (in part, to be able to afford sufficient fighters to sustain overall USAF fighter force structure requirements); this "high/low mix" concept would gain broad acceptance by the time of the flyoff between the prototypes, and would define the relationship of the F-15 and F-16 – and, subsequently, the F-22 Raptor and F-35 Lightning II.

Flyoff
The first YF-16 was rolled out on 13 December 1973, and its 90-minute-long “official” first flight was made at the Air Force Flight Test Center (AFFTC) at Edwards AFB, California, on 2 February 1974. Its actual first flight occurred accidentally during a high-speed taxi test on 20 January. While gathering speed, a roll-control oscillation caused a fin of the port-side wingtip-mounted missile and then the starboard stabilator to scrape the ground, and the aircraft then began to veer off the runway. The GD test pilot, Phil Oestricher, decided to lift off to avoid wrecking the machine, and safely landed it six minutes later. The slight damage was quickly repaired and the official first flight occurred on time. The YF-16’s first supersonic flight was accomplished on 5 February 1974, and the second YF-16 prototype flew for the first time on 9 May 1974. This was followed by the first flights of the Northrop’s YF-17 prototypes, which were achieved on 9 June and 21 August 1974, respectively. Altogether, the YF-16s would complete 330 sorties during the flyoff, accumulating a total of 417 flight hours; the YF-17s would accomplish 268 sorties.

Air Combat Fighter competition

Three factors would converge to turn the LWF into a serious acquisition program. First, four North Atlantic Treaty Organization (NATO) allies of the U.S. – Belgium, Denmark, the Netherlands, and Norway – were looking to replace their F-104G fighter-bomber variants of the F-104 Starfighter interceptor; furthermore, they were seeking an aircraft that their own aerospace industries could manufacture under license, as they had the F-104G. In early 1974, they reached an agreement with the U.S. that if the USAF placed orders for the aircraft winning the LWF flyoff, they would consider ordering it as well. Secondly, while the USAF was not particularly interested in a complementary air superiority fighter, it did need to begin replacing its F-105 Thunderchief fighter-bombers. Third, the U.S. Congress was seeking to achieve greater commonality in fighter procurements by the Air Force and Navy. The Congress, in August 1974, redirected funds for the Navy’s VFAX program to a new Navy Air Combat Fighter (NACF) program that would essentially be a navalized fighter-bomber variant of the LWF. These requirements meshed relatively well, but the timing of the procurement was driven by the timeframe needs of the four allies, who had formed a “Multinational Fighter Program Group” (MFPG) and were pressing for a U.S. decision by December 1974. The U.S. Air Force had planned to announce the LWF winner in May 1975, but this decision was advanced to the beginning of the year, and testing was accelerated. To reflect this new, more serious intent to procure a new aircraft, along with its reorientation toward a fighter-bomber design, the LWF program was rolled into a new Air Combat Fighter (ACF) competition in an announcement by U.S. Secretary of Defense James R. Schlesinger in April 1974. Schlesinger also made it clear that any ACF order would be for aircraft in addition to the F-15, which essentially ended opposition to the LWF.

ACF also raised the stakes for GD and Northrop because it brought in further competitors intent on securing the lucrative order that was touted at the time as “the arms deal of the century”. These were Dassault-Breguet’s Mirage F1M-53, the SEPECAT Jaguar, and a proposed derivative of the Saab Viggen styled the “Saab 37E Eurofighter” (which is not to be confused with the later and unrelated Eurofighter Typhoon). Northrop also offered another design, the P-530 Cobra, which looked very similar to its YF-17. The Jaguar and Cobra were dropped by the MFPG early on, leaving two European and the two U.S. LWF designs as candidates. On 11 September 1974, the U.S. Air Force confirmed firm plans to place an order for of the winning ACF design sufficient to equip five tactical fighter wings. On 13 January 1975, Secretary of the Air Force John L. McLucas announced that the YF-16 had been selected as the winner of the ACF competition.

The chief reasons given by the Secretary for the decision were the YF-16’s lower operating costs; greater range; and maneuver performance that was “significantly better” than that of the YF-17, especially at near-supersonic and supersonic speeds. The flight test program revealed that the YF-16 had superior acceleration, climb rates, endurance, and (except around Mach 0.7) turn rates. Another advantage was the fact that the YF-16 – unlike the YF-17 – employed the Pratt & Whitney F100 turbofan engine, which was the same powerplant used by the F-15; such commonality would lower the unit costs of the engines for both programs.

Shortly after selection of the YF-16, Secretary McLucas revealed that the USAF planned to order at least 650 and up to 1400 of the production version of the aircraft. The U.S. Air Force initially ordered 15 “Full-Scale Development” (FSD) aircraft (11 single-seat and 4 two-seat models) for its flight test program, but this would be reduced to 8 (6 F-16A and 2 F-16B). The Navy, however, announced on 2 May 1975, that it had decided not to buy the navalized F-16; instead, it would develop an aircraft derived from the YF-17, which would eventually become the McDonnell Douglas F/A-18 Hornet.

Moving into production
Manufacture of the FSD F-16s got underway at General Dynamics’ Fort Worth, Texas plant in late 1975, with the first example, an F-16A, being rolled out on 20 October 1976, followed by its first flight on 8 December. The initial two-seat model achieved its first flight on 8 August 1977. The initial production-standard F-16A flew for the first time on 7 August 1978 and its delivery was accepted by the USAF on 6 January 1979. The F-16 was given its formal nickname of “Fighting Falcon” on 21 July 1980, and it entered USAF operational service with the 388th Tactical Fighter Wing at Hill AFB on 1 October 1980.

On 7 June 1975, the four European partners, now known as the European Participation Group, signed up for 348 aircraft at the Paris Air Show. This was split among the European Participation Air Forces (EPAF) as 116 for Belgium, 58 for Denmark, 102 for the Netherlands, and 72 for Norway. These would be produced on two European production lines, one in the Netherlands at Fokker’s Schiphol-Oost facility and the other at SABCA’s Gossellies plant in Belgium; production would be divided among them as 184 and 164 units, respectively. Norway’s Kongsberg Vaapenfabrikk and Denmark’s Terma A/S also manufactured parts and subassemblies for the EPAF aircraft. European co-production was officially launched on 1 July 1977 at the Fokker factory. Beginning in mid-November 1977, Fokker-produced components were shipped to Fort Worth for assembly of fuselages, which were in turn shipped back to Europe (initially to Gossellies starting in January 1978); final assembly of EPAF-bound aircraft began at the Belgian plant on 15 February 1978, with deliveries to the Belgian Air Force beginning in January 1979. The Dutch line started up in April 1978 and delivered its first aircraft to the Royal Netherlands Air Force in June 1979. In 1980 the first aircraft were delivered to the Royal Norwegian Air Force by SABCA and to the Royal Danish Air Force by Fokker.

Since then, a further production line has been established at Ankara, Turkey, where Turkish Aerospace Industries (TAI) has produced 232 Block 30/40/50 F-16s under license for the Turkish Air Force during the late 1980s and 1990s, and has 30 Block 50 Advanced underway for delivery from 2010; TAI also built 46 Block 40s for Egypt in the mid-1990s. Korean Aerospace Industries opened another production line for the KF-16 program, producing 140 Block 52s from the mid-1990s to mid-2000s. If India selects the F-16IN for its Medium Multi-Role Combat Aircraft procurement, a sixth F-16 production line will be established in that nation to produce at least 108 fighters.

Evolution
After selection, the YF-16 design was altered for the production F-16. The fuselage was lengthened 10.6 in (0.269 m), a larger nose radome was fitted to house the AN/APG-66 radar, wing area was increased from 280 sq ft (26 m2) to 300 sq ft (28 m2), the tailfin height was decreased slightly, the ventral fins were enlarged, two more stores stations were added, and a single side-hinged nosewheel door replaced the original double doors. These modifications increased the F-16's weight approximately 25% over that of the YF-16 prototypes.

One needed change that would originally be discounted was the need for more pitch control to avoid deep stall conditions at high angles of attack. Model tests of the YF-16 conducted by the Langley Research Center revealed a potential problem, but no other laboratory was able to duplicate it. YF-16 flight tests were not sufficiently extensive to resolve the issue, but relevant flight testing on the FSD aircraft demonstrated that it was a real concern. As a result, the horizontal stabilizer areas were increased 25%; this so-called "big tail" was introduced on the Block 15 aircraft in 1981 and retrofitted later on earlier production aircraft. Besides significantly reducing (though not eliminating) the risk of deep stalls, the larger horizontal tails also improved stability and permitted faster takeoff rotation.

In the 1980s, the Multinational Staged Improvement Program (MSIP) was conducted to evolve new capabilities for the F-16, mitigate risks during technology development, and ensure its currency against a changing threat environment. The program upgraded the F-16 in three stages. Altogether, the MSIP process permitted quicker introduction of new capabilities, at lower costs, and with reduced risks compared to traditional stand-alone system enhancement and modernization programs. The F-16 has involved in other upgrade programs including service life extension programs in the 2000s.

Design
Overview

The F-16 is a single-engined, supersonic, multi-role tactical aircraft. The F-16 was designed to be a cost-effective combat "workhorse" that can perform various kinds of missions and maintain around-the-clock readiness. It is much smaller and lighter than its predecessors, but uses advanced aerodynamics and avionics, including the first use of a relaxed static stability/fly-by-wire (RSS/FBW) flight control system, to achieve enhanced maneuver performance. Highly nimble, the F-16 can pull 9-g maneuvers and can reach a maximum speed of over Mach 2.

The F-16 is equipped with an M61 Vulcan 20 mm cannon in the left wing root with the F-16A distinguished by having four vents behind the port for the M61 cannon whereas the subsequent F-16C has only two vents behind the cannon port.

Early models could also be armed with up to six AIM-9 Sidewinder heat-seeking short-range air-to-air missiles (AAM), including a single missile mounted on a dedicated rail launcher on each wingtip. Some variants can also employ the AIM-7 Sparrow long-range radar-guided AAM, and more recent versions can be equipped with the AIM-120 AMRAAM. It can also carry other AAM; a wide variety of air-to-ground missiles, rockets or bombs; electronic countermeasures (ECM), navigation, targeting or weapons pods; and fuel tanks on eleven hardpoints – six under the wings, two on wingtips and three under the fuselage.

General configuration
The F-16 design employs a cropped-delta planform incorporating wing-fuselage blending and forebody vortex-control strakes; a fixed-geometry, underslung air intake inlet supplying airflow to the single turbofan jet engine; a conventional tri-plane empennage arrangement with all-moving horizontal “stabilator” tailplanes; a pair of ventral fins beneath the fuselage aft of the wing’s trailing edge; a single-piece, bird-proof “bubble” canopy; and a tricycle landing gear configuration with the aft-retracting, steerable nose gear deploying a short distance behind the inlet lip. There is a boom-style aerial refueling receptacle located a short distance behind the rear of the canopy. Split-flap speedbrakes are located at the aft end of the wing-body fairing, and an arrestor hook is mounted underneath the aft fuselage. Another fairing is situated at the base of the vertical tail, beneath the bottom of the rudder, and is used to house various items of equipment such as ECM gear or drag chutes. Several later F-16 models, such as the F-16I variant of the Block 50 aircraft, also have a long dorsal fairing “bulge” that runs along the “spine” of the fuselage from the rear of the cockpit to the tail fairing; these fairings can be used to house additional equipment or fuel.

The F-16 was designed to be relatively inexpensive to build and much simpler to maintain than earlier-generation fighters. The airframe is built with about 80% aviation-grade aluminum alloys, 8% steel, 3% composites, and 1.5% titanium. Control surfaces such as the leading-edge flaps, tailerons, and ventral fins make extensive use of bonded aluminum honeycomb structural elements and graphite epoxy laminate skins. The F-16A had 228 access panels over the entire aircraft, about 80% of which can be reached without work stands. The number of lubrication points, fuel line connections, and replaceable modules was also greatly reduced compared to its predecessors.

Although the USAF’s LWF program had called for an aircraft structural life of only 4000 flight hours, and capable of achieving 7.33 g with 80% internal fuel, GD’s engineers decided from the start to design the F-16’s airframe life to last to 8000 hours and for 9-g maneuvers on full internal fuel. This proved advantageous when the aircraft’s mission was changed from solely air-to-air combat to multi-role operations. However, changes over time in actual versus planned operational usage and continued weight growth due to the addition of further systems have required several structural strengthening programs.

Wing and strake configuration

Aerodynamic studies in the early 1960s demonstrated that the phenomenon known as “vortex lift” could be beneficially harnessed by the utilization of highly swept wing configurations to reach higher angles of attack through use of the strong leading edge vortex flow off of a slender lifting surface. Since the F-16 was being optimized for high agility in air combat, GD’s designers chose a slender cropped-delta wing with a leading edge sweep of 40° and a straight trailing edge. To improve its ability to perform in a wide range of maneuvers, a variable-camber wing with a NACA 64A-204 airfoil was selected. The camber is adjusted through the use of leading-edge and trailing edge flaperons linked to a digital flight control system (FCS) that automatically adjusts them throughout the flight envelope.

This vortex lift effect can be increased by the addition of an extension of the leading edge of the wing at its root, the juncture with the fuselage, known as a strake. The strakes act as a sort of additional slender, elongated, short-span, triangular wing running from the actual wing root to a point further forward on the fuselage. Blended fillet-like into the fuselage, including along with the wing root, the strake generates a high-speed vortex that remains attached to the top of the wing as the angle of attack increases, thereby generating additional lift. This allows the aircraft to achieve angles of attack beyond the point at which it would normally stall. The use of strakes also permits the use of a smaller, lower-aspect-ratio wing, which in turn increases roll rates and directional stability, while decreasing aircraft weight. The resulting deeper wingroots also increase structural strength and rigidity, reduce structural weight, and increase internal fuel volume. As a result, the F-16’s high fuel fraction of 0.31 gives it a longer range than other fighter aircraft of similar size and configuration.

Flight controls

Negative static stability
The YF-16 was the world’s first aircraft intentionally designed to be slightly aerodynamically unstable. This technique, called "relaxed static stability" (RSS), was incorporated to further enhance the aircraft’s maneuver performance. Most aircraft are designed with positive static stability, which induces an aircraft to return to its original attitude following a disturbance. However, positive static stability hampers maneuverability, as the tendency to remain in its current attitude opposes the pilot’s effort to maneuver; on the other hand, an aircraft with negative static stability will, in the absence of control input, readily depart from level and controlled flight. Therefore, an aircraft with negative static stability will be more maneuverable than one that is positively stable. When supersonic, a negatively stable aircraft actually exhibits a more positive-trending (and in the F-16’s case, a net positive) static stability due to aerodynamic forces shifting aft between subsonic and supersonic flight. At subsonic speeds, however, the fighter is constantly on the verge of going out of control.

Fly-by-wire
To counter this tendency to depart from controlled flight—and avoid the need for constant minute trimming inputs by the pilot—the F-16 has a quadruplex (four-channel) fly-by-wire (FBW) flight control system (FLCS). The flight control computer (FLCC), which is the key component of the FLCS, accepts the pilot’s input from the stick and rudder controls, and manipulates the control surfaces in such a way as to produce the desired result without inducing a loss of control (known as "departing" controlled flight). The FLCC also takes thousands of measurements per second of the aircraft’s attitude, and automatically makes corrections to counter deviations from the flight path that were not input by the pilot, thereby allowing for stable flight. This has led to a common aphorism among F-16 pilots: “You don’t fly an F-16; it flies you.”

Unlike the YF-17 which featured a FBW system with traditional hydromechanical controls serving as a backup, the F-16’s designers took the innovative step of eliminating mechanical linkages between the stick and rudder pedals and the aerodynamic control surfaces. The F-16’s sole reliance on electronics and wires to relay flight commands, instead of the usual cables and mechanical linkage controls, gained the F-16 the early moniker of "the electric jet". The quadruplex design permits “graceful degradation” in flight control response in that the loss of one channel renders the FLCS a “triplex” system. The FLCC began as an analog system on the A/B variants, but has been supplanted by a digital computer system beginning with the F-16C/D Block 40.

Cockpit and ergonomics
One of the more notable features from a pilot’s perspective is the F-16’s exceptional field of view from the cockpit, a feature that is vital during air-to-air combat. The single-piece, bird-proof polycarbonate bubble canopy provides 360° all-round visibility, with a 40° down-look angle over the side of the aircraft, and 15° down over the nose (compared to the more common 12–13° of its predecessors); the pilot’s seat is mounted on an elevated heel line to accomplish this. Furthermore, the F-16's canopy lacks the forward bow frame found on most fighters, which obstructs some of the pilot’s forward vision. (The length of the tandem arrangement of two-seat F-16s does necessitate a frame between the pilots, however.)

The rocket-boosted ACES II zero/zero ejection seat is reclined at an unusually high tilt-back angle of 30°; the seats in older and contemporary fighters were typically tilted back at around 13–15°. The F-16’s seat-back angle was chosen to improve the pilot’s tolerance of high g forces, and to reduce his susceptibility to gravity-induced loss of consciousness. The increased seat angle, however, has also been associated with reports of increased risk of neck ache when not mitigated by proper use of the head-rest. Subsequent U.S. jet fighter designs have more modest tilt-back angles of 20°. Because of the extreme seat tilt-back angle and the thickness of its polycarbonate single-piece canopy, the F-16’s ejection seat lacks the steel rail canopy breakers found in most other aircraft’s ejection systems. Such breakers shatter a section of the canopy should it fail to open or jettison to permit emergency egress of the aircrew. On the F-16, crew ejection is accomplished by first jettisoning the entire canopy; as the relative wind pulls the canopy away from the plane, a lanyard triggers the seat’s rockets to fire.

The pilot flies the aircraft primarily by means of a side-stick controller mounted on the right-hand armrest (instead of the more common center-mounted stick) and an engine throttle on the left side; conventional rudder pedals are also employed. To enhance the pilot’s degree of control of the aircraft during high-g combat maneuvers, a number of function switches formerly scattered about the cockpit have been moved to "hands on throttle-and-stick (HOTAS)" controls found on both of these controllers. Simple hand pressure on the side-stick controller causes the transmission of electrical signals via the FBW system to adjust the various flight control surfaces used for maneuvering. Originally, the side-stick controller was non-moving, but this arrangement proved uncomfortable and difficult for pilots to adjust to, sometimes resulting in a tendency to "over-rotate" the aircraft during takeoffs, so the control stick was given a small amount of “play”. Since its introduction on the F-16, HOTAS controls have become a standard feature among modern fighters (although the side-stick application is less widespread).

The F-16 cockpit also has a Head-Up Display (HUD), which projects visual flight and combat information in symbological form in front of the pilot without obstructing his view. Being able to keep his head “out of the cockpit” further enhances the pilot’s situational awareness of what is occurring around him. Boeing’s Joint Helmet Mounted Cueing System (JHMCS) is also available from Block 52 onwards for use with high-off-boresight air-to-air missiles like the AIM-9X. JHMCS permits cuing the weapons system to the direction in which the pilot’s head is facing—even outside the HUD’s field of view—while still maintaining his situational awareness. JHMCS was first operationally deployed during Operation Iraqi Freedom.

The pilot obtains further flight and systems status information from multi-function displays (MFD). The left-hand MFD is the primary flight display (PFD), which generally shows radar and moving-map displays; the right-hand MFD is the system display (SD), which presents important information about the engine, landing gear, slat and flap settings, fuel quantities, and weapons status. Initially, the F-16A/B had only a single monochrome cathode ray tube (CRT) display to serve as the PFD, with system information provided by a variety of traditional “steam gauges”. The MLU introduced the SD MFD in a cockpit made compatible for usage of night-vision goggles (NVG). These CRT displays were replaced by color liquid crystal displays on the Block 50/52. The Block 60 features three programmable and interchangeable color MFDs (CMFD) with picture-in-picture capability that is able to overlay the full tactical situation display on the moving map.

Radar
The F-16A/B was originally equipped with the Westinghouse (now Northrop Grumman) solid-state AN/APG-66 pulse-Doppler fire-control radar. Its slotted planar-array antenna was designed to be sufficiently compact to fit into the F-16’s relatively small nose. In uplook mode, the APG-66 uses a low pulse-repetition frequency (PRF) for medium- and high-altitude target detection in a low-clutter environment, and in downlook employs a medium PRF for heavy clutter environments. It has four operating frequencies within the X band, and provides four air-to-air and seven air-to-ground operating modes for combat, even at night or in bad weather. The Block 15’s APG-66(V)2 model added a new, more powerful signal processor, higher output power, improved reliability, and increased range in a clutter or jamming environments. The Mid-Life Update (MLU) program further upgrades this to the APG-66(V)2A model, which features higher speed and memory.

The mechanically scanned AN/APG-68 X-band pulse-Doppler radar, an evolution of the APG-66, was introduced with the F-16C/D Block 25. The APG-68 has greater range and resolution, as well as 25 operating modes, including ground-mapping, Doppler beam-sharpening, ground moving target, sea target, and track-while-scan (TWS) for up to ten targets. The Block 40/42’s APG-68(V)1 model added full compatibility with Lockheed Martin Low-Altitude Navigation and Targeting Infra-Red for Night (LANTIRN) pods, and a high-PRF pulse-Doppler track mode to provide continuous-wave (CW) target illumination for semi-active radar-homing (SARH) missiles like the AIM-7 Sparrow. The Block 50/52 F-16s initially received the more reliable APG-68(V)5 which has a programmable signal processor employing Very-High-Speed Integrated Circuit (VHSIC) technology. The Advanced Block 50/52 (or 50+/52+) are equipped with the APG-68(V)9 radar which has a 30% greater air-to-air detection range, and a synthetic aperture radar (SAR) mode for high-resolution mapping and target detection and recognition. In August 2004, Northrop Grumman received a contract to begin upgrading the APG-68 radars of the Block 40/42/50/52 aircraft to the (V)10 standard, which will provide the F-16 with all-weather autonomous detection and targeting for the use of Global Positioning System (GPS)-aided precision weapons. It also adds SAR mapping and terrain-following (TF) modes, as well as interleaving of all modes.

The F-16E/F is outfitted with Northrop Grumman’s AN/APG-80 Active Electronically Scanned Array (AESA) radar, making it only the third fighter to be so equipped.

In July 2007, Raytheon announced that it was developing a new Raytheon Next Generation Radar (RANGR) based on its earlier AN/APG-79 AESA radar as an alternative candidate to Northrop Grumman’s AN/APG-68 and AN/APG-80 for new-build F-16s as well as retrofit of existing ones. On 1 November 2007, Boeing selected this design for development under the USAF’s F-15E Radar Modernization Program (RMP).