The Block 60 upgrade to the F-16 is the biggest and best yet, says Lockheed Martin, and breathes new life into the 27-year-old aircraft

At a time in its life when fighter programmes usually start to show their age - two decades after entering service - the Lockheed Martin F-16 is undergoing a fundamental rejuvenation. The Block 60 aircraft under development for the United Arab Emirates (UAE) represents the biggest change in the F-16 since the Block 40 night-attack aircraft was introduced in 1988.

The Block 60 upgrade introduces an autonomous, all-weather precision targeting and strike capability, extends range, and expands on the F-16's already legendary air-to-air performance. "We're not changing much," jokes John Bean, vice president UAE Block 60 programme. "Just new core avionics, new electronic warfare suite, new flight control system, new cockpit, new sensors, new engine, and new support and training systems."

The UAE chose Lockheed Martin'sF-16 Block 60 over the Dassault Rafale and Eurofighter Typhoon in May 1998, but talks over technology release delayed to March last year the signature of a $6.43billion contract for development and production of 80 aircraft. By June 2000, everything was approved by the US Government and Lockheed Martin received its export licence and a down payment, officially launching the programme.

The direct commercial contract includes a substantial amount of non-recurring expenditure to cover new technology in the aircraft, support and training systems. As well as customer funding, there is also a "fair amount" of industry investment, Lockheed Martin says, as the company expects the F-16 to attract further sales (see panel).

Sixteen months in, programme officials say development is on track. The preliminary design review was completed in August and metal for the first aircraft was cut this month. "This is a very large development programme. So far, the customer is satisfied we are on track," Bean says. First flight of a Block 60 F-16 is planned for late 2003, and the first will be ferried to the UAE a year later. All 80 aircraft - 55 single-seaters and 25 two-seaters - are scheduled to be in-country and to full operational standard by mid-2007.

Fundamental change

The Block 60 is not just another update to the F-16. "It is a very fundamental change," says Lockheed Martin. "There are more changes from the Block 50 to the Block 60 than the Block 30, 40 and 50 updates combined." Programme officials pay tribute to the longevity and flexibility of the original F-16 design, which has evolved over 20 years from a day visual air-to-air fighter to an all-weather precision strike aircraft.

Externally, the aircraft is virtually unchanged from the Block 50, and its structure will be shared by the improved Block 50 Plus under development simultaneously. "We are taking the extra steps necessary to produce a common airframe," says Lockheed Martin. The increased maximum take-off weight - 23,130kg (51,000lb) compared with the Block 50's 21,770kg - is within the range planned for the Block 50 Plus.

Empty weight is increased substantially, from 8,700kg to 9,300kg, because systems carried externally on the Block 50/50 Plus are housed internally in the Block 60.This includes the navigation forward-looking infrared (FLIR) sensor, targeting FLIR, automatic terrain-following system and targeting for anti-radiation missiles, which is a function of the internal electronicwarfare system. "Almost all sensors and electronic warfare pods outside the aircraft are now inside the aircraft," Lockheed Martin says.

After a competition, the UAE selected the General Electric F110-132 to power its Block 60 F-16s. The engine produces 32,500lb (145kN) of thrust, up 10% from the 29,500lb of the F110-129 powering Block 50/50 Plus F-16s. GE is paying for development of the enhanced performance engine, drawing on US Air Force funding for improvements to the F110. Pratt & Whitney is continuing development of a similarly rated version of its F100 engine to offer other potential customers.

Internally, there is substantial subsystem redesign to accommodate the new avionics and sensors. The core avionics are totally changed, as the UAE wanted the most advanced systems available. The new mission computer is based on a Motorola PowerPC commercial processor and has 40 times the speed and memory of the current F-16 computer. All software, including that in the digital flight control system - over 2 million lines of code in total - is being written or rewritten in the C++ commercial high-order language. "There are no older languages left in the aircraft," says Lockheed Martin. "The new software architecture is more sustainable."

Other avionics include a new display processor for the colour cockpit, advanced data-transfer unit, embedded global-positioning/inertial navigation system, eight-ship infraflight datalink, identification friend-or-foe interrogator and solid-state digital video recorder. Provisions are included for a differential GPS landing system, and for a helmet-mounted display. The UAE has yet to choose between the USA's Joint Helmet-Mounted Cueing System and the BAE Systems helmet-mounted display for the Eurofighter Typhoon, so the aircraft will be equipped to accept either.

A fibre-optic high-speed data network using commercial Fibre Channel technology ties the new mission avionics together. With 1,000 times the capacity of the military 1553 databus the Fibre Channel is needed to handle the volume of data generated by the Block 60's sensors, particularly the active electronically scanned array (AESA) radar. "All sensor integration is via fibre-optic channel," says Lockheed Martin.

Block 60 operational capabilities will be developed and fielded incrementally, mainly as software updates. Flight testing will begin with Standard 0. The initial operational release, Standard 1, is already under test in the laboratory and simulator, and is scheduled to be fielded in late 2004 with in-country delivery of the first aircraft, followed by the Standard 2 update in early 2006 and upgrade to the Standard 3 full operational capability in mid-2007.

Advanced sensors

Heading up the new sensor suite is the Northrop Grumman APG-80 Agile Beam Radar, an AESA capable of interleaving air-to-air, air-to-ground and terrain following modes so they appear simultaneous. Performance is classified, but the radar has almost twice the air-to-air detection range of the APG-68(V)7 in the Block 50 and also provides "very high resolution" synthetic aperture radar (SAR) ground imaging.

Northrop Grumman is also developing the Block 60's Integrated FLIR and Targeting System. This includes a navigation sensor in a turret on top of the nose, and a targeting sensor in a "podlet" attached to the engine intake. Both are mid-wave (3-5Ám) focal-plane array infrared sensors. The navigation FLIR has a fixed field-of-view matching the head-up display, but has growth capability to a head-steered sensor coupled to the helmet-mounted display.

Originally installed in a matching turret under the nose, the targeting FLIR migrated to a separate pod as requirements evolved. The 280mm (11in)-diameter podlet generates less drag and avoids disturbing airflow into the engine, says Lockheed Martin. The pod is designed to remain on the aircraft and will be cleared for the F-16's full 9g flight envelope. It is not a standalone pod. Power and cooling is provided by the aircraft and the electronics are still in the nose, while the pod houses the dual-magnification (2x and 9x) FLIR and laser designator.

In November 2000, the UAE selected Northrop Grumman to supply the Block 60's all-new electronic warfare (EW) suite, described by Lockheed Martin as "the most capable ever fielded". The internal system performs the traditional radar warning receiver functions, plus electronic support measures and electronic intelligence gathering, and provides targeting for anti-radiation missiles.

Lockheed Martin says the countermeasures system can handle "all possible threats" using a digital techniques generator, onboard jammers and a fibre-optic towed decoy. The Block 60 also carries a large supply of chaff and flares in up to 14 dispensers in the fuselage and pylons. The "significant integration" of the EW system with the aircraft's sensor suite represents the "toughest technical challenge" in the Block 60 programme, officials say.

System changes necessitated by the new sensor suite include increasing the capacity of the F-16's dual environmental control systems to provide liquid cooling for the active-array radar's solid-state transmit/receive modules. The air data system is also redesigned to increase reliability while improving radar performance by eliminating the nose probe.

There is a dramatic change within the tight confines of the F-16 cockpit with the move to three large, 125 x 175mm, colour liquid-crystal displays (LCDs) and the elimination of all gauges. Other changes include a new upfront controller with data-entry keypad and display, digital fuel panel and solid-state standby instrument. Cockpit and external lighting is compatible with night-vision goggles.

The two-seat Block 60 features a missionised aft cockpit. The sidestick and throttle can be decoupled from those in the front cockpit, allowing independent operation of the rear-seat controls and displays. While the two-seater can be flown as a trainer, with the aft displays mimicking those in the front, independent operation of the rear cockpit increases effectiveness and reduces workload on demanding missions, Lockheed Martin says. Both cockpits have provisions for helmet displays.

Familiar concept

Cockpit operation will be familiar to experienced F-16 pilots, despite the topographic transformation. The basic hands-on-throttle-and-stick (HOTAS) control concept is unchanged and there is high degree of automation and integration of the Block 60's advanced sensors. "Pilots transitioning from the Block 50 will understand the display and sensor management philosophy," Lockheed Martin says.

The large LCDs allow "picture-in-picture" formats - for example, an air-to-air presentation with a vertical situation display along the bottom, or a SAR image with FLIR and weapon video at the bottom. The central tactical situation display can present all sensor data overlaid on a moving map, with room along the bottom for a weapon schematic. Using HOTAS, the pilot can cycle through the formats on one display or rotate the formats between displays.

Sophisticated autoflight capabilities include advanced autopilot modes and, for the first time, autothrottle. The aircraft is capable of flying a four-dimensional flightpath automatically, countering threats that pop up en route and releasing weapons at the pre-planned place and time. This has necessitated new flight control computers with increased capacity, the first major change to the F-16's quadruplex fly-by-wire system since the Block 40 analogue-to-digital upgrade.

The Block 60 is capable of automatic terrain following using the radar, or passively using the digital terrain system. Hosted in the data transfer unit, this terrain database also provides ground collision avoidance capability. The terrain data is also used to generate the moving map and display features such as threat intervisibility. This allows the engagement volumes of ground threats to be displayed in real time as the aircraft manoeuvres.

Longer legs

A major objective of the Block 60 design was to substantially increase the F-16's payload/range performance, to compete with that offered by the Boeing F-15E. Lockheed Martin says several factors combine to give the aircraft about twice the payload/range performance of the Block 50, including reduced cruise drag from eliminating the external pods and improved engine thrust-specific fuel consumption.

The major contributor is increased fuel capacity in the form of conformal fuel tanks (CFTs) attached to the upper fuselage and larger, 2,270litres (600USgal), tanks carried under the wing. The single-seat Block 60 can carry 9,070kg of fuel: 3,080kg internally, 1,360kg in the CFTs, 3,700kg in two 2,270litres tanks and 930kg in a centreline 2,270litre tank. This is an increase of around 85% over the standard F-16C, and allows the Block 60 to carry double the payload over the same range or fly close to twice the distance with the same payload, says Lockheed Martin.

The aluminium CFTs are removable, but are designed to remain on the aircraft throughout its 9g flight envelope without degrading the F-16's performance. "Sustained g, acceleration and turn performance are all on a par with the Block 50," says Lockheed Martin. The conformal tanks generate "a fraction" of the drag of the two 1,400litre tanks F-16s normally carry on the inboard wing pylons, and can be used to free these stations for additional weapons.

A substantial portion of the Block 60 development cost covers new support and training equipment. This includes all-electronic, laptop-based technical manuals, new intermediate-level avionics automatic test equipment and an in-country engine maintenance shop. There is also a new PC-based mission planning network and a next-generation training system with full-dome, unit-level and egress procedures trainers. All the equipment is cheaper than that available today, says Lockheed Martin.

Block 60 development is on a "very aggressive timetable", officials acknowledge, but the contract has allowed the company to use commercial initiatives to streamline the programme. CFT development is already under way for the Block 50 Plus F-16, and sensor testing will be performed on a surrogate aircraft ahead of the Block 60's first flight. Under its firm fixed-price commercial contract, Lockheed Martin is responsible for generating and analysing all Block 60 test data. "We have a very thorough procurement specification. We know the pass/fail criteria," say programme officials. "We are comfortable with the way things are progressing."

Source: Flight International