F-16 Modernization : 9781288333998 : 21 Nov 2012 : The next-generation F/A-22 Raptor and the F-35 Joint Strike Fighter (JSF) are scheduled to become a significant part of the USAF force structure in the next 5-15 years. Until sufficient quantities of these aircraft are operational, the United States Air Force will rely on legacy systems such as the F-16. Unless the USAF upgrades its F-16 fleet, however, it will be faced with not one, but two gaps in capability. The F-16 has been produced in quantities of nearly 4,000, of which the USAF owns a significant share. Unfortunately, these aircraft are aging faster than expected, and will require structural upgrades to extend their service life. Without these upgrades, over 1000 F-16s in service today will be unusable in the 2012 timeframe, before initial operational capability of the JSF. The result will be a gap in force structure, and thus in overall capabilities. However, the F-16 requires more than structural upgrades.