All F-16s are not created equal. Fighting Falcons rolling out of the factory today are nothing like earlier versions. Some differences are visible—larger control surfaces; wider inlets; tinted canopies; squared landing lights; and various antennas, vents, bumps, and blisters. Most differences require more than the naked eye to see—structural beef-ups, improved engines, digitized electronics, vastly increased computing capacity, and software changes to accommodate new functions, sensors, and weapons.
The all-glass cockpit (no mechanical gauges) of the latest F-16s is the manifestation of many of these improvements. Three large five- by seven-inch color multifunction displays transmit information from a variety of sensors to the pilot in straightforward color graphics. The picture-in-picture capability of each display allows up to nine simultaneous display subsets at any given time. The cockpit features hands-on throttle and sidestick switch controls, night vision goggle-compatible lighting, a color moving map, and a large head-up display. The head-up display is supplemented by helmet-mounted cueing systems that allow pilots to target weapons by simply turning their heads.
The original F-16 was designed as a lightweight air-to-air day fighter. Air-to-ground missions immediately transformed the first production F-16s into multirole fighters. The F-16s that followed expanded and refined these roles with beyond-visual-range missiles, infrared sensors, precision-guided munitions, and a plethora of other capabilities. Current and planned versions of the F-16 build on these refinements, enhancing capabilities even further.
But the fundamental strengths of the original design remain. At the heart of every Fighting Falcon is the lightweight fighter concept championed by John Boyd and the other members of what came to be known as the Lightweight Fighter Mafia in the Air Force and Department of Defense. This group favored simple and small fighter designs that could change direction and speed faster than their potential adversaries and were harder to detect, visually and electronically. The Lightweight Fighter Mafia advocated designs that were inexpensive to produce, operate, and maintain. They advocated using technology to increase effectiveness or reduce cost. They went so far as to question and thoroughly analyze the basic assumptions of how fighters were judged and compared.
Engineers in Fort Worth transformed these ideas into reality in the 1970s. The resulting lightweight fighter set new performance standards for combat aircraft. The basic design combined a host of advanced technologies that had never been used in previous operational fighters. A blended wing-body, variable camber wings, and forebody strakes provided extra lift and control. Fly-by-wire flight controls improved response time and replaced heavy hydromechanical systems with lighter and smaller electronic systems. Relaxed static stability, made possible by the fly-by-wire system, greatly enhanced agility. A side-mounted throttle and stick, head-up display, thirty-degree seat back angle, hands-on controls, and bubble canopy improved the pilot’s g-tolerance and situational awareness.
All of these technologies had been explored before in a variety of other aircraft and research programs. But the F-16 prototype, or YF-16, was the first airplane to incorporate all of them.
The development of the YF-16 optimized a design for performance. The evolution of the production F-16s, on the other hand, was a balancing act between adding and improving capabilities and maintaining the optimized performance of the original design.
Capability improvements take many forms: countermeasures, infrared sensors, laser targeting devices, missionized rear cockpits, dorsal fairings, datalinks, satellite phones, helmet-mounted cueing systems, conformal fuel tanks, large color displays, all-glass cockpits, reconnaissance pods, and auto-recovery systems. Each new capability benefits from its own evolutionary process. For example, the active electronically scanned array radar, already operational in F-16s, functions seamlessly with many of these other systems and acts as a capability multiplier in itself. All of these improvement leaps are packed into an airframe still capable of sustaining nine g’s and of out-performing other fourth-generation fighters.
Pratt & Whitney and General Electric have added to the evolution with impressive improvements in engine performance. The original Pratt & Whitney engine on the YF-16 developed about 23,000 pounds of thrust. The engines on the Block 50/52 aircraft develop nearly 30,000 pounds of thrust. The GE F110-GE-132 engine on the Block 60 F-16 is rated at 32,500 pounds of thrust. The next round of engine improvements could boost this figure to more than 50,000 pounds. So, even though the F-16’s overall weight has increased, its thrust-to-weight ratio has improved as well.
However, the Lightweight Fighter Mafia will point out that thrust-to-weight ratio is not the only indicator of aircraft performance. The figure doesn’t account for the effects of wing loading and aerodynamic drag. A better measure of performance is energy rate (or Ps), which is a function of thrust, weight, velocity, and drag. Every external payload extracts a performance price in aerodynamic drag. And F-16s rarely fly without a few stores hanging under the wing.
Technology comes to the rescue again. Advances in electronic miniaturization have resulted in lighter, more compact hardware that, in turn, significantly reduces drag. The latest navigation and targeting pods, for example, are smaller, lighter, and aerodynamically cleaner than first-generation pods. Electronic countermeasure systems have shrunk, too, and have more recently found their way under the F-16’s skin, eliminating even more drag. Weaponeers are making bombs and missiles smaller, lighter, and more streamlined. Drag reductions have often accompanied efforts to add more systems and weapons to the airplane and to make the airplane more stealthy.
While the F-16 today benefits from the electronic revolution, the original designers did not anticipate it. In fact, they purposely kept the aircraft as dense as possible to prevent additional systems—and the extra weight they would bring—from being placed inside the airframe. Technology advances have allowed much more capability to be packed into that same space or, in some cases, in much less space.
Keeping up with all the varieties of the F-16 is no small task. The job is simplified, though, because most changes to the F-16 are made in groups, or blocks, to track items on the production line. Whenever a new production configuration for the F-16 is established, the block number increases. Block is an important term in tracking F-16 evolution.
The first production aircraft following the two YF prototypes and the eight full-scale development F-16s were Blocks 1 and 5. (From Block 30/32 on, a major block designation ending in 0 signifies a General Electric engine; one ending in 2 signifies a Pratt & Whitney engine.) The highest block designation, however, is Block 60, which is flown by the United Arab Emirates. Because the US Air Force has discontinued F-16 purchases to begin transitioning to the F-35, the block designations will likely end at 60. Some of the latest F-16 configurations are now identified with a country-representative nomenclature. For example, F-16IN is the proposed configuration for India.
The A in F-16A refers to Blocks 1 through 20 single-seat aircraft. The B in F-16B refers to the two-seat version. The letters C and D were substituted for A and B, respectively, beginning with Block 25. The new series letters emphasize the major differences occurring between Blocks 15 and 25. Block 60 denotes the transition from the F-16C/D to the F-16E/F.
The YF-16 was chosen over the YF-17 in the Lightweight Fighter competition in 1975. Work began on the first of eight full-scale development, or FSD, F-16s, incorporating the first major—mostly internal—design changes. The designers were intent on retaining the outstanding flying qualities of the original design. So no changes that would degrade the prototype’s aerodynamics were made. At the same time, they had to adapt the airplane to amplified air-to-ground requirements that foreshadowed the F-16’s transition into a multirole fighter. The overall length grew by thirteen inches. The nose, which accounts for about three of those additional inches, acquired a slight droop to accommodate the Westinghouse APG-66 multimode radar.
To respond to the need for larger air-to-ground payloads, the wing and tail surfaces were enlarged to carry the extra weight. The wing area grew from 280 to 300 square feet, which is about as much as it could grow without requiring additional internal bulkheads to lengthen the fuselage. The horizontal tails and ventral fins grew about fifteen percent. The flaperons and speed brakes grew by about ten percent. An additional hardpoint was placed under each wing, giving the aircraft a total of nine. The airframe was structurally strengthened for these new loads as well.
Other changes in the FSD aircraft included a lighter weight Stencel SIIIS ejection seat, a simpler single door instead of twin doors on the nose landing gear bay, and a self-contained jet fuel engine starter. The canopy transparency was strengthened to withstand a four-pound, 350-knot bird strike. The radome was hinged to ease access to the radar.
Besides helping to win the Lightweight Fighter competition, the YF-16 also validated the aerodynamics, propulsion, and handling qualities of the aircraft’s basic design. With the major design issues out of the way, engineers concentrated more on internal details—such as the electrical system, hydraulics, and avionics—with the FSD aircraft. The high readiness and flight rates of the first production F-16s are attributable to the maturity level achieved with the prototype design. The FSD aircraft had no block numbers, though they are often referred to as Block 0 F-16s.
After the prototype and FSD programs, the first Block 1 F-16 (serial number 78-0001) was flown for the first time in August 1978 and delivered to the Air Force that same month. The aircraft was first assigned to the 388th Tactical Fighter Wing at Hill AFB, Utah, and later became an interceptor with the 125th Fighter Interceptor Group in Jacksonville, Florida, followed by a tour at the 158th Fighter Interceptor Group in Burlington, Vermont. It then was flown by the 127th Tactical Fighter Wing at Selfridge Air National Guard Base, Michigan. The aircraft was eventually sent to Lowry AFB, Colorado, as a student trainer. The first operational F-16 is now on display at Langley AFB, Virginia.
Ninety-four Block 1 and 197 Block 5 F-16s were manufactured through 1981 for the US Air Force and four European Participating Air Forces. Most Block 1 and Block 5 aircraft were upgraded in 1982 to a Block 10 standard through a program called Pacer Loft. New production Block 10 aircraft (312 total) were built through 1980. The differences between these early F-16 versions are relatively minor, involving improvements to make the airplane more reliable and more easily maintained. All production F-16s beginning with Block 1 are outfitted with ACES II ejection seats.
A word about nicknames: Tactical Air Command, now Air Combat Command, officially christened the F-16A as the Fighting Falcon. But that name never found wide use on the flightline. As with many aircraft, the unofficial nickname the pilots pinned on the F-16 did catch on: Viper.
The 330th production F-16 was the first of 983 Block 15 aircraft manufactured in five countries and subsequently assembled on three production lines (Fort Worth, Belgium, and Netherlands). The production of the Block 15 spanned fourteen years. Of the more than 4,400 F-16s manufactured to date, Block 15 aircraft are the most numerous.
The transition from Block 10 to Block 15 resulted in two hardpoints added to the inlet chin and designated as stations 5R and 5L. The larger horizontal tail is the most noticeable difference between Block 15 and previous F-16 versions. The tail grew in area by about thirty percent. The larger tail offset the shift in center of gravity brought on by the weight of the two chin hardpoints and their associated sensor pods and structure. The larger tail also provides better stability and control authority, especially at higher angles of attack.
Block 15 aircraft received an operational capability upgrade, or OCU, beginning in 1988. The upgrade added a data transfer unit and a radar altimeter. The radar was improved, and the fire control and stores control computers were expanded. OCU also allowed Block 15 aircraft to fire the AGM-119 Penguin anti-ship, the AGM-65 Maverick air-to-ground, and the AIM-120 AMRAAM air-to-air missiles. Block 15 aircraft built from 1988 had OCU, a larger head-up display, and the Pratt & Whitney F100-PW-220 engine. The last production Block 15 was delivered to Thailand in 1996. Fifteen air arms fly Block 15 aircraft today, including the US Navy.
The Air Defense F-16 is a variant of the Block 15 OCU F-16 equipped with additional systems for the air-to-air role. It has improved APG-66A radar, an APX-109 identification friend or foe interrogator, ARC-200 high-frequency radio, and a 150,000-candlepower spotlight mounted on the left side of the forward fuselage. In the late 1980s and early 1990s, 271 Block 15 airframes were converted to the Air Defense configuration. The first converted aircraft were delivered in early 1989. All of the aircraft initially went to the Air National Guard. The Guard stopped flying the Air Defense version of the F-16 in 2007. Fargo, North Dakota, was the last Guard unit to operate that type in the United States. However, more than sixty of this F-16 version are still flown by Jordan, Italy, and Thailand
The transition of the F-16 from Block 15 to Block 25 marks the evolution from the F-16A/B to the F-16C/D. Block 25 enabled the F-16 to carry AMRAAM as a baseline weapon as well as carrying night/precision ground-attack capabilities. An improved fire control computer, an improved stores management computer, and an inertial navigation system were added along with multifunction displays, new data transfer unit, radar altimeter, and anti-jam UHF radio.
The Block 25 F-16 also received the improved Westinghouse (now Northrop Grumman) AN/APG-68 radar, which offered increased range, better resolution, and more operating modes. Block 25 featured new upfront controls, a larger head-up display, and two head-down multifunction displays. All Block 25s were originally powered by the Pratt & Whitney F100-PW-200, but the engines have since been upgraded to the -220E configuration. The first of 244 Block 25 F-16s flew in June 1984. Block 25 is the only F-16 to be employed exclusively by the US Air Force.
Block 30/32 added two new engines to the F-16 line—the Pratt & Whitney F100-PW-220 and the General Electric F110-GE-100. The aircraft’s engine bays are common to both engines by design. Block 30 designates the GE engine, and Block 32 designates the Pratt & Whitney engine. A larger inlet was introduced at Block 30D for the GE-powered F-16s, which are often called big-mouth F-16s. The larger inlet, formally called the modular common inlet duct, allows the GE engine to produce its full thrust at lower airspeeds.
The smaller inlet, called a normal shock inlet, has not changed for the -220 and subsequent Pratt & Whitney engines. A Pratt & Whitney F100-PW-229 engine powered the Variable Inflight Stability Test Aircraft, or VISTA/F-16, which featured the larger inlet. This is the only F-16 with a large inlet and a Pratt & Whitney engine.
Block 30/32 can carry the AGM-45 Shrike and the AGM-88A high-speed anti-radiation missiles, or HARM. Like the Block 25, it can carry the AGM-65 Maverick missile. Changes at Block 30D allowed the aircraft to carry twice as many chaff/flare dispensers for self-protection, and the forward radar warning receiver antennas were relocated to the leading-edge flap. These beer can-shaped antennas have since been retrofitted onto all previous F-16C/D aircraft. Block 30/32 has a crash-survivable flight data recorder, voice message unit, and expanded memory for the multifunction displays. The first of 733 Block 30/32 F-16s was delivered in July 1987; the airplane was manufactured through 1989.
The F-16N manufactured for the US Navy was a Block 30 variant. It was powered by the GE F110-GE-100 engine and had the small inlet associated with early Block 30 production. The F-16N also carried the APG-66 radar of the F-16A models and minor structural differences for meeting Navy requirements. The aircraft had no internal 20-mm gun. Twenty-two F-16Ns and four TF-16Ns (two-seaters) were built from 1987 to 1988. They were used for dissimilar air-to-air training with three Navy adversary squadrons and at the Navy’s Fighter Weapons School (Top Gun).
While the Block 30 F-16Ns were retired from Navy service in 1994 for budgetary reasons, the US Navy once again began flying Fighting Falcons in early 2002 when the first of ten single-seat and four two-seat Block 15 F-16s were delivered to NAS Fallon in Nevada (the new home of Top Gun). These aircraft, with distinctive paint schemes, are low-hour F-16A/Bs restored after being stored at Davis-Monthan AFB, Arizona.
With Block 40/42, the F-16 gained capabilities for navigation and precision attack at night and in all weather conditions and traded its original analog flight controls for a digital system and new core avionics.
The landing gear of Block 40/42 was beefed up and extended to handle the LANTIRN targeting and navigation pods and more extensive air-to-ground loads. By design, the landing gear bay doors bulge slightly to handle the larger wheels and tires. The LANTIRN pods also necessitated moving the landing lights from the struts of the main landing gear to the leading inside edge of the nose gear door. A larger head-up display was needed for LANTIRN as well. The wide-angle raster HUD, as it is called, is capable of displaying the infrared image from the LANTIRN navigation pod used in low-altitude night navigation.
The precision weapons incorporated by Block 40/42 include the GBU-10, GBU-12, and GBU-24 Paveway family of laser-guided bombs as well as the GBU-15 glide bomb.
Block 40/42 also featured the addition of the APG-68(V5) radar, automatic terrain following (part of the LANTIRN system), global positioning system, full provisions for internal electronic countermeasures, an enhanced envelope gun sight, and a capability for bombing moving targets.
Production of Block 40/42 began in 1988 and ran through 1995. Twenty-one more Block 40s were built for Egypt, and ten single-seat Block 40s were built for Bahrain during 1999 to 2000.
US Air Force Block 40 aircraft are now equipped and flying missions with night vision goggles and with a datalink system. This system receives highly accurate position information from a forward air controller on the ground. The system then inputs the data into the weapon system computer and displays it as a waypoint on the head-up display.
Block 20 refers to new-production F-16As that incorporate significant avionic enhancements, including a modular mission computer replacing three other computers. The processing speed of the computer is more than 740 times faster than the computer in the original F-16. It has more than 180 times the memory. An improved radar, the APG-66(V2), features increased detection and tracking ranges and the ability to track more targets.
The Mid-Life Update program, or MLU, refers to the 300 retrofitted F-16A/B Belgian, Danish, Dutch, and Norwegian aircraft. These aircraft were also structurally upgraded to meet an 8,000-hour airframe lifespan in a program called Falcon UP (for unos programmum). Several other current F-16 operators have upgraded their earlier model Fighting Falcons as well.
Block 20 and MLU F-16s have wide-angle head-up displays, color multifunction cockpit displays, upfront controls (a set of programmable pushbuttons placed just below the head-up display), a Block 50-style sidestick and throttle, ring laser inertial navigation systems, miniaturized global positioning systems, digital terrain systems, improved data modems, and advanced interrogators for identifying friendly or foe aircraft. The lighting in the cockpit is compatible with night-vision systems. The aircraft also have provisions for microwave landing systems and helmet-mounted displays.
The Block 50/52 F-16 is recognized for its ability to carry the AGM-88 HARM in the suppression of enemy air defenses, or SEAD, missions. The F-16 can carry as many as four HARMs.
An avionics launcher interface computer allows the F-16 to launch the HARM missile. US Air Force F-16s have been upgraded to carry the HARM Targeting System, or HTS, pod on the left intake hardpoint so it can be combined with laser targeting pods designed to fit on the right intake hardpoint. The HTS pod contains a hypersensitive receiver that detects, classifies, and ranges threats and passes the information to the HARM and to the cockpit displays. With the targeting system, the F-16 has full autonomous HARM capability.
The Block 50/52 F-16 is equipped with the APG-68(V9) radar, which offers longer range detection against air targets and higher reliability. The Block 50/52 also includes a ring laser gyro inertial navigation system, a global positioning system receiver, a larger capacity data transfer cartridge, a digital terrain system data transfer cartridge, a cockpit compatible with night vision systems, an improved data modem, an ALR-56M advanced radar warning receiver, an ALE-47 threat-adaptive countermeasure system, and an advanced interrogator for identifying friendly aircraft. An upgraded programmable display generator has four times the memory and seven times the processor speed of the system it replaces. New VHF/FM antennas increase reception ranges. The Block 50/52 is powered by increased performance engines—the General Electric F110-GE-129 and the Pratt & Whitney F100-PW-229—each rated to deliver over 29,000 pounds of thrust in afterburner. Block 50/52 are the first F-16 versions to fully integrate the AGM-84 Harpoon anti-shipping missile.
New production Block 50/52 aircraft ordered after 1996 include color multifunction displays, the modular mission computer, and a three-channel video tape recorder. The throughput of the new computer dramatically increases the processing power of the F-16 and allows the airplane to continue to grow indefinitely. All international versions of the Block 50/52 have LANTIRN capability.
The first Block 50/52 was delivered to the US Air Force in 1991. More than 800 have been delivered so far from production lines in Fort Worth, Korea, and Turkey. (The Fort Worth production line is currently the only active F-16 line, but the Turkey line is scheduled to start producing Block 50 aircraft beginning in 2011.)
The engines that power the F-16 have improved in more ways than in maximum thrust. Engines used in early F-16s required from six to eight seconds to spool up from idle to afterburner. Since then, electronic controls have replaced hydromechanical systems. The changes allow current engines to go from idle to full afterburner in two seconds. This responsiveness has a huge payoff in performance and in aircraft handling. Engine reliability and ease of maintenance have also been improved significantly. Today’s F-16 engines can be expected to deliver eight to ten years of operational service between depot inspections.
Digital engine controls, first introduced on Pratt & Whitney-powered F-16s in 1986, have also improved performance. Older hydromechanical controls had to be trimmed to operate at the most challenging point within the F-16’s flight envelope. Digital engine controls automatically adjust to the operating environment, so that they optimize engine performance at all points within the flight envelope. This optimization has increased thrust by more than ten percent in some areas of the F-16 flight envelope. All engines being built today for the F-16 have digital engine controls.
With all the varieties of the F-16 produced through the years, the US Air Force decided to standardize its F-16 fleet to simplify logistics, maintenance, and training. The service now flies Block 40/42 and Block 50/52 F-16s almost exclusively in its active duty units. Exceptions include Block 30/32 F-16s at the Aggressor squadrons in Nevada and Alaska and Block 25 F-16s in training squadrons at Luke AFB, Arizona. Block 25 and Block 30/32 aircraft are concentrated in Air National Guard and Air Force Reserve Command units. A few Reserve Component units do already fly more advanced versions of the F-16.
More recent improvements to the F-16 fleet have reduced operation and support costs, further increased combat capability, and helped standardize the Air Force fleet. The Common Configuration Implementation Program, or CCIP, added color displays, common missile warning systems, and the modular mission computer to Block 40/42 and Block 50/52 F-16s as well as an advanced datalink, called Link-16, that is standard for US and NATO aircraft. The upgrade also includes a helmet-mounted cueing system. This system works with the high-off-boresight AIM-9X air-to-air missile as well as with other slewable sensors. More than 200 Block 50/52 and 450 Block 40/42 aircraft were involved in the two programs. Guard, Reserve, and active duty Air Force units are now operational with the upgrades.
The F-16 Block 60, also known as the Desert Falcon, is the most advanced F-16 produced to date. An internal, forward-looking infrared navigation sensor mounted as a ball turret on the upper left nose is the main feature that distinguishes the Block 60 from previous F-16s. Both single- and two-seat aircraft carry conformal fuel tanks.
The Desert Falcon’s increased-thrust GE-132 engine helps compensate for the increase in weight and payload over the basic F-16. Internal differences, on the other hand, add up to a huge improvement in capability.
The Desert Falcon has many automated modes, including autopilot, auto-throttle, an automatic ground collision avoidance system, and a pilot-actuated recovery system. The recovery system allows pilots to recover the aircraft with the push of a button the moment they sense they have lost situational awareness. The Block 60’s electronic warfare system, produced by Northrop Grumman, is the most sophisticated subsystem on the aircraft. It provides threat warning, threat emitter locating capability, and increased situational awareness to pilots. A new data transfer cartridge holds thirty gigabytes of information. A fiber-optic databus handles the throughput and speed needed for many of these systems. The maintenance system is laptop-based.
The APG-80 agile beam radar underpins many of the new capabilities of the Block 60. The radar, produced by Northrop Grumman, is an advanced electronically scanned array offering much greater detection ranges. The array consists of a bank of transmit/receive modules attached to a fixed array that generates the radar beam, which can be directed almost instantaneously. The electronic approach, instead of a mechanical approach, allows radar modes to be interleaved. For example, the radar can continuously search for and track multiple targets and simultaneously perform multiple functions such as air-to-air search and track, air-to-ground targeting, and terrain following. The radar vastly improves the pilot’s situational awareness.
Block 60’s General Electric F110-GE-132 turbofan engine produces approximately 32,500 pounds of thrust in maximum afterburner. The engine is a derivative of the F110-GE-129, a 29,000-pound thrust class engine that powers the majority of F-16C fighters worldwide.
The F110-GE-132 has also been selected to power the F-16IN, the Fighting Falcon proposed for India for the Medium Multi Role Combat Aircraft program. If selected, the F-16IN will be the most advanced F-16 design to date. This aircraft will feature a refueling boom that retracts from the right conformal fuel tank. The boom allows the F-16IN to operate with India Air Force probe-and-drogue style aerial refueling systems similar to those used by the US Navy. The refueling boom is now being flight tested in Fort Worth. Even without aerial refueling, an F-16IN with conformal tanks can fly from Bangalore in the south of India to Leh in the north.
Several other systems distinguish the F-16IN from the Block 60, including an electronic warfare system and radar modes tailored for India, dragchute, datalink, satellite communication, and a helmet-mounted cueing system. The F-16IN will carry the Sniper targeting pod as well.
The YF-16 was flown for the first time in 1974 at the Air Force Flight Test Center at Edwards AFB, California. The first production F-16 rolled out of the factory in Fort Worth in August 1978. Since then, more than 4,400 F-16s have rolled off assembly lines in five countries. Twenty-five air forces will soon be flying the Fighting Falcon. Other countries are considering buying the fighter to modernize their fleets. F-16 production is expected for another ten years, or more, and front-line service and sustainment will extend beyond 2030.
The F-16’s long production run and low cost have given the airplane latitude to expand its capabilities. The F-16 has grown extensively within the external lines of the first F-16. The limited external changes are a tribute to the optimization of the original design and to huge advancements in avionics. The airplane continues to grow in terms of new weapons and sensors.
The present state of the F-16 encompasses a broad range of configurations. While the earliest F-16s perch atop poles for public display, others test the latest weapon and sensor technology. Those rolling off the factory line represent the most advanced fourth-generation fighter produced today. Even though the F-16 has been flying for thirty years, its evolution continues to build on the fundamental strengths of its original design.