Pakistan obtained a total of 40 Block 15 F-16A/Bs, including 28 F-16As and 12 F-16Bs, with initial deliveries in 1983 under the "Peace Gate" program. Pakistan's F-16s saw a surprising amount of air combat during the Soviet war in neighboring Afghanistan during the 1980s. Soviet aircraft would often follow Afghan Mujahedin fighters fleeing over the border into Pakistan, and the Pakistanis would take them on. Pakistani F-16s claimed about a dozen kills. Apparently they also lost an F-16 to another F-16 in a "friendly fire" incident while in pursuit of an intruder. This may have been the first and possibly the only Viper to be lost in air combat.
In the early 1990s Pakistan was to receive 28 more Block 15 OCU F-16A/Bs, including 13 F-16As and 15 F-16Bs, but the order was frozen in response to American worries about the Pakistani nuclear program. The 28 aircraft were mothballed in the "boneyard" at Davis-Monthan Air Force Base in Arizona. They were pulled out of storage in early 2003, with 13 of them provided to the USAF as test and evaluation machines, one of them transferred to the US Air National Guard, and the remaining 14 transferred to the US Navy for use as aggressor aircraft.
The Block 15 F-16A/B featured more significant changes, implemented as part of a "Multinational Staged Improvement Program (MSIP)". Block 15 was the first phase of the MSIP effort, and was also referred to as "MSIP I". The major visible change was a new horizontal tailplane that featured a rear extension that gave it 30% more area. The new "big tail" improved stability, and permitted faster takeoff rotation and flight at higher angles of attack. Other changes included improvements to the AN/APG-66 radar, installation of a new "Have Quick" secure radio, and a modified cockpit instrument layout.
At the end of Block 15 production an "Operational Capability Upgrade (OCU)" was introduced that featured the improved P&W F100-PW-220 engine, which corrected many of the reliability problems that had affected the F100 and featured a "digital electronic engine control (DEEC)"; a bigger "head-up display (HUD)" built by Marconi in the UK; support for the AN/ALQ-131 jammer pod; a ring-laser gyro inertial navigation system; some structural reinforcement; and wiring to support future avionics updates and the AIM-120 Advanced Medium Range AAM (AMRAAM), then in development. Production moved to the Block 15 OCU F-16 in 1988. Most earlier aircraft in service were updated to the same specification.
In the early 1990s, a "Mid-Life Upgrade (MLU)" program was begun to upgrade F-16A/Bs to modern Viper standards. The Block 15MLU upgrade featured:
A new wide-angle HUD.
Support for the AIM-120 AMRAAM and provision for inlet-mounted targeting pods.
A Global Position System / Inertial Navigation System (GPS / INS) navigation system, with a "Digital Terrain System" ground-following capability.
An improved modular mission computer that replaced several older computers.
Improved AN/APG-66(V2) radar.
A night-vision-goggle (NVG) compatible cockpit with multifunction displays (MFDs).
An "integrated data modem (IDM)" and an improved IFF system.
The Air Force was not entirely happy with the weight growth and performance decline of the Block 40/42, and so the next sub variant, the "Block 50/52", was not optimized for the night attack role and featured new, more powerful, GE and P&W "Improved Performance Engines (IPE)".
The Block 50 is fitted with the GE F110-GE-129 IPE and the Block 52 is fitted with the P&W F100-PW-220 IPE. Both engine variants have 129 kN (13,150 kgp / 29,000 lbf) afterburning thrust, 20% more than the original-fit F100-PW-220 turbofan, and are much more powerful in low-level flight than previous models. With the IPE variant the F100 finally caught up to F110 performance, a lesson in the virtues of competition not lost on the Air Force.
Some early production Block 52 machines were temporarily retrofitted with the older F110-PW-220 due to bugs in the new engine variant. The F100-PW-229 IPE features a distinctive gloss-black exhaust not used in the GE F110 or earlier P&W F100 variants. Some Block 40/42s have been refitted with IPE engines.
The Block 50/52 also features AN/APG-68(V)3 radar with improved reliability and signal processing capabilities plus more modes; a new, lighter, cheaper HUD; and an "Improved Data Modem" data link. The new block includes the digital flight capability and features the HUD of the Block 30/32, but includes the digital flight control system, reinforced airframe, and stronger landing gear of the Block 40/42.
Initial flight of an F110-powered Block 50 F-16C was on 22 October 1991, with first flight of a Block 52 F-16D following on 1 April 1992. First flight of an F100-powered Block 52 F-16C was on 22 October 1992, with first flight of a Block 52 F-16D on 24 November 1992.
* Nothing was changed on the Block 50/52 to rule out carriage of LANTIRN, but as far as the USAF is concerned that's a job for the Block 40/42. Some Block 50/52 machines are capable of carrying the Texas Instruments "AN/ASQ-213 HARM Targeting System (HTS)" to give them a "suppression of enemy air defenses (SEAD)" capability. The HTS is a small pod that is carried on the right side of the engine inlet and allows a Viper to detect, identify, and target adversary radar and other emitters for attack with the aircraft's AGM-88 "High-Speed ARM (HARM)" missiles.
"Wild Weasel" defense suppression aircraft have traditionally been two-seat machines, such as the the McDonnell Douglas F-4G Wild Weasel Phantom the Block 50/52 with HTS replaced, and some critics claim the single-seat F-16C with HTS is an inadequate replacement. Defenders counter that improved data processing and software has allowed a single-seat aircraft to perform the mission perfectly well.
[1.2] F-16A & F-16B DESCRIBED
* The F-16A that emerged from this development process is a neat, sleek, dart like aircraft with swept wings; a degree of wing-body blending; a conventional tail assembly, with all-moving horizontal tail planes; and twin ventral fins. The wing-body blending allows the aircraft's body to provide lift. The wing has a leading-edge sweep of 40 degrees and a straight trailing edge, with full-span leading-edge flaps and large "flaperons" on the trailing edge to provide improved landing performance and combat maneuverability. Airbrakes are fitted between the horizontal tail plane and the engine exhaust, with the airbrakes opening top and bottom.
The F-16A's appearance is very similar to that of the YF-16 prototypes, but there are clear differences. The YF-16 was about 30 centimeters (a foot) shorter, with a smaller nose as the original plan wasn't to fit a sophisticated radar; had a slightly shorter tailfin, smaller ventral fins, slightly smaller wings and fuel tankage, and a more complicated nose wheel door arrangement; and, lacking operational kit, weighed only about 75% as much.
The F-16A is of conventional construction, with about 80% of the airframe built with aircraft aluminum alloys, 8% with steel, 3% with composites, and 1.5% with titanium. There are 228 access panels over the entire aircraft, simplifying maintenance. About 80% of the aircraft can be reached without work stands, and the number of lubrication points, fuel-line connections, and replaceable modules has been greatly reduced compared to fighters of an earlier generation.
The F-16A was originally powered by a single P&W F100-PW-200 afterburning turbofan engine with 65.2 kN (6,655 kgp / 14,670 lbf) maximum dry thrust and 106 kN (10,810 kgp / 23,830 lbf) afterburning thrust. It was a modified version of the F100-PW-100 developed for the twin-engine F-15, adapted for single-engine operation with such features as a redundant fuel system to improve reliability. The kidney-shaped engine intake is fitted on the belly of the aircraft below the cockpit. The positioning of the intake permits adequate airflow at high angles of attack. The inlet geometry is fixed, not variable.
The F-16A's fuel capacity is surprisingly large for the aircraft's size and configuration, 31% of its fully-loaded weight, and gives the aircraft correspondingly long range. The large fuel capacity is one of the benefits of the wing-body blending, which along with aerodynamic efficiency provides additional volume that can be used for fuel tanks. There is a boom refueling socket in the center of the back, normally marked by a white "fishbone" pattern to guide a tanker boom operator. It does not appear that any production F-16s have ever been fitted with refueling probe for probe-and-drogue refueling.
The F-16A has tricycle landing gear, all with single wheels, the front gear retracting backward underneath the intake and the main gear retracting forward into the fuselage. The position of the nose gear behind the intake helps reduce the chance of foreign-object ingestion, a potential problem given the size and position of the intake. A distinctive drag-parachute compartment can be fitted behind the rear of the base of the tailfin, though the USAF and most other users have not specified this item. There is also a runway arresting hook under the tail behind the ventral fins. It is unclear if the arresting hook is a standard feature.
The pilot sits under a single-piece polycarbonate bubble canopy on a McDonnell Douglas "Advanced Concept Ejection Seat (ACES) II" "zero-zero" (zero speed, zero altitude) ejection seat. The rocket-boosted ACES II ejection seat, designed for the F-15 Eagle, is reclined 30 degrees and the pilot's legs are raised, helping to help deal with high-gee maneuvers. However it appears that the specific reason for slanting the seat in such a way was to allow it to fit in the slender nose of the aircraft and the gee-resistance is just an unintended benefit. Incidentally, the two YF-16s used Escapac ejection seats, while the FSD F-16s used Stencel SIIIS ejection seats.
The canopy is hardened against bird strikes and provides an outstanding all-round view. The pilot holds a throttle in the left hand and a side stick controller in the other, both studded with "hands on throttle and stick (HOTAS)" controls. The side stick controller was originally pressure-sensitive, not moveable like a joystick, but would later be modified to provide a slight "give" for pilot feedback.
GENERAL DYNAMICS F-16A:
spec metric english
wing span with AAMs 10.0 meters 32 feet 10 inches
length 15.03 meters 49 feet 4 inches
height 5.09 meters 16 feet 8 inches
empty weight 8,275 kilograms 18,220 pounds
MTO weight 19,185 kilograms 42,300 pounds
max speed 2,125 KPH 1,320 MPH / 1,145 KT
service ceiling 15,250 meters 50,000 feet
combat radius 925 KM 575 MI / 500 NMI
The aircraft features a quadruplex (quadruple redundant) analog-electronic FBW flight control system. An FBW system is required because the F-16A is designed for "relaxed stability" or "dynamic instability", meaning it doesn't tend to fly right if left to itself. This provides increased maneuverability, but also dictates an automatic flight-control system to keep the aircraft flying right. The FBW system features built-in limiters to prevent stalls, with override capability for the pitch control if the pilot wants it.
The F-16 is one of the first relaxed-stability fighters to be put into production. The FBW system led pilots to call the F-16 the "Electric Jet", but it appears that this nickname has fallen out of use as FBW systems have become more common.
Avionics for the F-16A include defensive countermeasures, UHF & VHF radios, identification friend or foe (IFF) unit, TACAN beacon navigation set, ILS landing set, and multimode radar. The backbone of the countermeasures system is the Itek AN/ALR-69 radar warning receiver (RWR), featuring antennas on the top and bottom of the rear of the tailfin, on each side of the nose, and under the engine intake. Warning is provided on cockpit displays and the pilot's headphones. Elements of the countermeasures suite vary from user to user, but jamming pods can be carried on a centerline stores pylon.
Although the LWF competition was for a simple, clear-weather air-superiority fighter, of course the Air Force decided after selecting the F-16 for production that they wanted more capability, beginning a process of "mission creep" that continues with the F-16 to this day. It is a tribute to the fundamental soundness of the design that it has been able to take on such an increasing load of missions.
In any case, instead of being a simple daylight air-combat fighter, the F-16A as built is basically an all-weather fighter-bomber. Although the YF-16 was built with the idea that it would have very simple radar for air combat, resulting in the small nose, the F-16A features a relatively sophisticated Westinghouse AN/APG-66 multimode radar providing "eyes" for both air combat and ground-attack in night or bad weather.
The AN/APG-66 is a medium-pulse-rate Doppler radar with a flat slotted antenna. The radar was designed to be compact enough to fit into the F-16's relatively small nose. It provides four operating modes for air-to-air combat and seven for air-to-ground combat, with a "videogame"-like digital display that provides text and symbology to make the radar easier to use.
Surprisingly, the AN/APG-66 did not provide guidance capability for the AIM-7 Sparrow medium-range semi active radar homing (SARH) AAM. This omission had its roots in the original concept of the F-16 as a simple, cheap fighter. It would later be seen to be a serious error in judgment, as it meant that in principle the F-16 could be picked out of the sky with impunity by an adversary fighter carrying medium-range missiles.
Although there had been a tendency to delete gun armament in the previous generation of jet fighters such as the Phantom, this had been recognized as a blunder, and the F-16A has built-in armament consisting of a single General Electric six-barreled Gatling-type 20 millimeter M61A1 cannon, with 500 rounds of ammunition. The gun fires out a port on top of the left wing root extension, just behind the pilot's seat, with the ammunition drum behind the cockpit. The position of the cannon muzzle prevents gun gas ingestion into the air intake and avoids blinding the pilot with muzzle flash.
The F-16A has a single centerline stores pylon, three stores pylons on each wing, and wingtip launch rails for Sidewinder air to air missiles (AAMs), for a total of nine stores pylons. Maximum external load is 9,275 kilograms (20,450 pounds).
The two-seat F-16B has exactly the same dimensions as the single-seat F-16A, with the second seat in the F-16B obtained by removing a fuselage fuel tank, reducing internal fuel capacity by 17%. The F-16B was intended as a conversion trainer and has dual controls. Both variants are produced on the same production lines. The F-16B is fully combat-capable, allowing it to be used both for training and for operational missions where the workload requires two air crew. About one F-16B was acquired for every six F-16As.
* The P&W F100 turbofan was an impressive engine but it was not perfect. The latest generation of American fighters like the F-16 had unprecedented high-speed maneuverability, and as high-speed maneuvers required some skillful juggling of the throttle, this placed an entirely unexpected level of stress on the engines of these fighters, reducing their lifetimes. The problem was known as "low cycle fatigue".
The F100 also suffered from a tendency to stall under some conditions, and in certain cases this could lead to a condition where fuel pooled up in the afterburner, ignited in an explosion, pooled up again, exploded again, and so on at a rate of several times a second. It would all but shake the pilot's teeth out.
To keep Pratt & Whitney honest, the military worked with General Electric to develop an alternate engine, based on the GE F101 afterburning turbofan used on the Rockwell B-1 bomber. The first FSD F-16A was refitted with the GE F101 and performed its initial flight on 19 December 1980. The only visible distinction between the "F-16/101", as it was called, and a stock F-16 was that the sides of the engine exhaust were noticeably curved, not straight as they were for the P&W F100 engine.
The F-16/101 made 58 test flights to July 1981. The GE power plant was not adopted for the time being, but the wheels had been set in motion that would eventually see a GE engine fitted to the F-16.
* The Air Force's enthusiasm for the F-16 grew in time. It was a very hot machine, one of the first operational aircraft that could subject a pilot to more gees than the airframe could handle. The Viper's thrust-to-weight ratio allowed it to accelerate while climbing straight up. One pilot commented: "I can take off and climb straight to 10,000 feet without crossing the fence around the airport."
The high seat and frameless canopy give an F-16 pilot an outstanding view. Pilots quickly became confident in its capability for air-to-air combat and its ground attack capabilities. The lack of a medium-range AAM was troublesome, though that problem was eventually fixed. Some pilots were a little insecure about the single-engine configuration, though it hasn't led to real trouble in terms of loss rates, and the F-16 tends to be somewhat troublesome to land. Like many aircraft that are designed to be very aerodynamically efficient it tends to want to stay in the air and may dance around a bit on its wheels when it first makes contact with the runway.
[2.7] F-16 EXTERNAL STORES
* The F-16's most characteristic weapon is the AIM-9 Sidewinder AAM, usually carried on the wingtip launch rails. Most US machines carry the AIM-9L/M all-aspect variants, but some foreign users have had to settle for the slightly less sophisticated AIM-9P-4 variant.
Along with the Sidewinder, Vipers have also carried the medium-range AIM-7M Sparrow, though only a few nations acquired this weapon for the F-16, as well as the Sparrow's follow-on, the AIM-120 AMRAAM. A few nations have qualified AAMs from other nations, such as the Israeli Rafael Python or French Matra Magic series of heat seeking AAMs, in the same class as the Sidewinder.
The F-16 has been qualified with the new US AIM-9X AAM, as well as the comparable British "Advanced Short Range AAM (ASRAAM)". Both of these are "off-bore sight" AAMs, meaning they don't have to be pointed directly at the target before launch. They are instead "cued" to the target by a pilot's helmet-mounted sight, and a "Joint Helmet-Mounted Cueing System (JHMCS)" has been developed for the F-16. There are rumors that some foreign F-16s have been qualified for the new medium-range Matra MICA AAM.
* As discussed earlier, although the F-16 was initially designed as a lightweight air combat fighter, it was originally tasked in USAF service as a strike aircraft, and accordingly qualified for standard iron bombs and cluster munitions. It is certainly possible for an F-16 to carry other "dumb" munitions such as napalm tanks and 70 millimeter (2.75 inch) unguided rocket pods, but these seem to be relatively unusual stores. US Vipers are known to carry Durandal runway-buster bombs.
The world's air forces have been migrating towards smart weapons, however, and US F-16s generally carry guided weapons, particularly laser-guided bombs (LGBs) or AGM-65 Maverick guided missiles, with the LGBs guided by LANTIRN pods. Other targeting pods are in use by some foreign air forces, such as the Thales (previously Thomson-CSF) "Atlis II" pod, and the Israeli Rafael "Litening" pod. A variant of the Litening pod is even used by some USANG Vipers. The Air Force has committed to the new Lockheed Martin "Sniper" pod to replace LANTIRN.
Interestingly, LGB targeting pods seem to be often carried by single-seat Vipers, though flying an airplane in the face of enemy defenses while trying to keep crosshairs on a target sounds a bit tricky. F-16s have carried electro-optic guided bombs (EOGBs) such as the GBU-15 glide bomb, which requires carriage of an AN/AXQ-14 data link pod. It appears that EOGBs are usually carried by two-seat Vipers.
Block 50/52 machines with the HARM Targeting System also carry the AGM-88 HARM, and the Block 50/52 has been qualified to carry the AGM-84 Harpoon anti-ship missile. Foreign users also carry their own stores. For example, Norwegian F-16s carry the Penguin Mark 3 anti-ship missile and Israeli Vipers have carried the big Rafael "Popeye" electro-optic guided standoff missile.
F-16s have now or are being qualified to use the latest generation of US guided weapons, including the "Joint Direct Attack Munitions (JDAM}" GPS-guided bomb; the "Joint Stand-Off Weapon (JSOW)" glide bomb; the "Wind Corrected Munitions Dispenser (WCMD)" inertial-guided cluster bomb; and the "Joint Air to Surface Standoff Missile (JASSM)" cruise missile.
The US military has improved battlefield networking technology to improve the Viper's attack capability. One scheme, named "Sure Strike" that was introduced in 1996, allows a ground spotter team to pinpoint a target and relay its coordinates to a Viper over the aircraft's data link, with the target marked out on the fighter's HUD. A newer scheme, known as "Gold Strike", also allows target imagery to be sent to a Viper from a reconnaissance platform. The new "Link-16" data link is being fitted to USAF Vipers to further improve data connectivity.
* F-16s have been adapted to the reconnaissance role, carrying a range of reconnaissance pods. In 1986, an F-16D was modified into a more optimized reconnaissance configuration, carrying a multi sensor bathtub-style pack on the centerline. The pack was big enough to make ground clearance minimal. This experimental fit was at least informally referred to as the "RF-16D", and labeled "F-16 Recce" (pronounced "recky") on its tailfin. Nothing came of this experiment.
In the mid-1990s, after almost giving up on the tactical reconnaissance mission, the Air Force decided to try again to give the F-16 a reconnaissance capability, with the reconnaissance mission to be handed to the USANG. Lockheed Martin developed a prototype pod, the "Electro-Optical 1 (EO-1)" with a digital camera controlled by a laptop computer. This led to the production of four interim pods known only as the "Richmond recce pod", with a digital camera, magnetic-tape recorder, and a GPS receiver to help log image coordinates. The Richmond recce pod has seen service in the Balkans. It was replaced by the definitive "AN/ASD-11 Theatre Airborne Reconnaissance System (TARS)", with a number of improvements. All three of these pods are carried on the centerline station.
The USAF has flown their F-16s with external jammer pods, usually mounted on the centerline pylon, with the Viper initially carrying the AN/ALQ-131 pod. The current USAF jammer pod is the Raytheon AN/ALQ-184(V)9, which can carry four Raytheon AN/ALE-50 towed decoys. As discussed in the next chapter, several foreign users have selected their own countermeasures suites. The Per Udsen company in Denmark has come up with a clever "Pylon Integrated Dispenser System (PIDS)", which fits chaff-flare dispensers to the rear of the outboard stores pylon on each wing. PIDS is in service with a number of foreign user as well as the USANG and USAF Reserve, and the company has now developed a "PID+" with missile warning capabilities.
One of the more usual external stores carried by the F-16 is the "MXU-48" cargo pod, which is used to carry the pilot's personal effects and other gear when the fighter is being deployed to a new base.
written by a Viper pilot.