As a thank to the Israeli's for staying out of the war in Iraq in 1991, the United States government sold 50 retired F-16s to Israel. The program was called Peace Marbel IV. The F-16s had been retired to AMARC but still had a few flying hours left on the airframe. When the aircraft arrived in Israel, they still had the USAF paint scheme but unit markings were quickly applied. These F-16s were not painted in the standard Israeli F-16 paint scheme till the individual aircraft went through depot level maintenance.
These airframes were standard block 10 versions that previously were in service with the USAF’s ANG units. In the mid nineties all those airframes received minor updates that included upgrading these airframes to the block 15 standards (included installing the larger stabs, P&W F100-220E engine, and modifications that allow them to execute their air defence mission). Other upgrades to these airframes have been kept to an absolute minimum.
However, since Israel still flies those airframes till today, their original number of flying hours (set at 4,000) must be long overdue, these airframes must have received structural upgrades to strengthen the airframes to cope with higher flying hours. Since these older airframes are merely updated to perform specialized attack missions and since Israel possesses other F-16 types that can handle this job more efficiently, these vipers are only used in the air defence role.
IDFAF F-16A block 5 #107
of the 116th squadron "The Flying wing Squadron" land at it's home base. Note the 6.5 kill markings. [Airliners.net
photo by Ofer Zidon]