Block 15 is the most common F-16 version, embodying the originial design philosophy of the F-16 as a light-weight dogfighter. A prime example are these US Navy
aggressors, still used as opposing "Red air" forces at NAS
With over 750 aircraft produced, the block 15
series is the most widely deployed F-16 model. This number is even more impressive if you include the F-16 block 15 ADF
and block 15 OCU variants, bringing the total to over 1,200 airframes. Block 15s introduced the larger stabilizer, enforced inlet duct, upgraded radar, etc. and were delivered to 13 countries. Block 15 OCU (Operational Capabilities Upgrade) introduced the PW F100-220E engine, new gun nozzle, beefed-up landing gear, etc.
Many A/B models have been converted into either block 15 ADF (Air Defense Fighter) or block 20 MLU
(Mid-Life update). The ADF was a variant specifically designed to replace the fighters in USAF's interception/air defense squadrons and was the first F-16 variant to support the AIM-7 Sparrow. The block 20 MLU conversion's main purpose was to extend the service life of the EPAF
nations' block 15 fleets by introducing many advanced C/D features into the A/B versions, such as upgraded radar, introduction of the AIM-120 AMRAAM
, glass-cockpit, expanded Modular Mission Computer, etc. A total of 259 aircraft (of an intended 271) were converted to ADF with USAF as only customer, while 387 aircraft were converted to MLU (February 2010), key customers being Belgium
, the Netherlands
. A small number of block 20 was also new-built for Taiwan
Second, third, and fourth places are taken by the block 50/52, block 40/42 and block 30/32. As a whole, far more C/D versions where built than A/B versions. The C/D brings numerous advantages: block 30/32 introduced the GE
F110-100 engine, block 40/42 improved ground attack capabilities greatly with the LANTIRN
suite and block 50/52 included support for the AGM-88 missile and thus SEAD capability. All aircraft currently on order are block 50/52 variants. The block 60
, an advanced variant built for the UAEAF
has so far not seen any takers besides the United Arab Emirateb, although variants of the block 60
have been offered to India amongst others.
Two types of engines were used for the C/D models: the PW F100-200E/229 (which equips block 32/42/52 models), and the GE
F110-100/129 (block 30/40/50). The main reason for this is that the USAF wanted to use a dual-sourcing strategy for engines. The split is about 2 to 1 in favour of the General Electric engine, with over 1,550 aircraft fitted with it and about 800 with the Pratt & Whitney engine.