The first production variants were the F-16A (single seat) and F-16B (two seat) aircraft. These were built in production blocks numbered 1, 5, 10, and 15. The USAF retired its 296 Block 5/10 F-16s in the early 1990s.
Block 15 F-16A/Bs introduced an extended horizontal stabilator and a track-while-scan mode for the radar. Most surviving Block 15 F-16s equip Air National Guard and test units. Of 467 Block 15 F-16As and F-16Bs, 272 were converted to F-16A/B ADF (Air Defense Fighter) standard with upgraded APG-66 radar compatible with AIM-7 Sparrow AAMs, advanced IFF, and improved ECCM and radios. Although most ADFs are in storage three ANG units remain equipped with the type.
From 1988 214 new-build F-16As for export were manufactured to Block 15 OCU standard with wide-angle HUD, ring laser INS, increased MTOW capability more reliable Dash 220 engine, compatibility with AIM-9P-4 missiles and provision for ALQ-131 jamming pods. Belgium, Denmark, Norway and the Netherlands bought 521 F-16A/Bs of various Blocks (including OCU) from 1979 to 1992 and are currently are equipped with indigenous tactical reconnaissance pods. Taiwan is receiving 120 F-16As and 30 F-16Bs to Block 20 standard (new-build) with an avionics configuration similar to that of the MLU. Other F-16A/B operators are Egypt, Indonesia, Israel, Singapore, Thailand and Venezuela. In 1998 Jordan received 16 surplus ex-USAF F-16A/B ADFs, while Italy is leasing 30 Block 15 F-16ADFs as interim F-104 replacements. Production of F-16A/Bs totals 1 736 aircraft, comprising 1 425 F-16As and 311 F-16Bs.
The F-16C (single seat) and F-16D (two seat) is the most important operational F-16 variant with over 1 750 examples in service with nine operators. Compared to the preceding F-16A/B series, the F-16C/D introduced improved ground and all-weather attack capabilities, plus provision for BVR missiles. Major features include a wide-angle HUD, Hughes APG-68 multi-mode radar and a weapons interface for AGM-65D and AMRAAM missiles.
The first Block 25 F-16C flew on 19 June 1984. Subsequent models feature a reconfigured engine bay with options for higher-thrust GE F110 (Block 30/40) or P&W F100 (Block 32/42) engines. F-16s with the latter powerplant have enlarged air intakes. Block 30/32 aircraft can carry AGM-88A and AIM-120 weapons.
From 1988, Block 40/42 Night Falcons introduced LANTIRN navigation and targeting pods (carried on the sides of the air intake), APG-68V radar, AGM-88B HARM II, digital flight controls, automatic terrain following and strengthened undercarriage. Block 30-42 F-16C/Ds are operated by Bahrain, Egypt, Greece, Israel, South Korea and Turkey. License manufacture is undertaken in Korea and in Turkey.
Many F-16Ds delivered to Israel have been subsequently fitted with a bulged spine, housing unidentified indigenous avionics that are probably associated with a defense suppression role. The USAF received a total of 1 155 F-16C/Ds. These remain the service's primary tactical combat aircraft, the Block 40/42 Night Falcons making up over half on the night/precision strike/attack force.
In late 1991 General Dynamics began delivering the latest operational F-16 variants, the Block 50/52 F-16C/D. These feature APG-68(V)5 radar with improved memory and more modes, a new NVG-compatible wide-angle HUD, improved avionics computer, ALE-47 chaff/flare dispenser, ALR-56M RWR, Have Quick IIA radio, Have Sync anti-jam VHF and full HARM integration. These latest F-16 are powered by the IPE (Improved Performance Engine) versions of two standard GE and P&W engines. About 100 of the USAF's 289+ Block 50/52 F-16C/Ds have been raised to Block 50/52 standard with provision for the ASQ-213 HARM Targeting System pod carried under the starboard side of the intake to provide a limited Wild Weasel defense-suppression capability. Smart weapons capability is being applied to this model as well as previous versions. Export operators comprise Greece, South Korea, Singapore and Turkey. Local production is undertaken in both South Korea and Turkey. Singapore operates two-seat F-16Ds fitted with enlarged dorsal spines similar to those of Israeli aircraft. Greece is buying up to 58 F-16s to improved Block 50+ configuration with upgraded radar, a helmet-mounted cueing system, conformal fuel tanks and stealthy nozzles.
The latest F-16 development is the Block 60/62 standard (or F-16E/F) that is being developed in response to a requirement from the United Arab Emirates. Changes including agile beam radar, internal FLIR targeting system, an advanced internal ECM system, an advanced cockpit, conformal fuel tanks and an uprated engine. These Desert Falcons were delivered between 2004-2007. Production of the F-16 remains assured until at least 2009.