At the turn of the 21st Century, as the USAF found conducting combat operations over Iraq and Afghanistan with increasingly aging aircraft that were leftovers from the Cold War it took stock of its aircraft inventory and came to the following observation
As a system’s cumulative operating time increases, the probability of its failure tends to increase, decreasing the system’s potential reliability. Reliability also decreases when the conditions under which the system was designed to operate change. Many of these aircraft are at critical points in their life cycles. For example, by 2001 many F-16s had reached 2,400 hours flying time, a significant point in an 8,000-hour service life. As these aircraft age and operating conditions changed, the reliability of systems and components decreases, and failures occur more often, which increased maintenance costs. Increased failures affect aircraft maintainability, requiring more maintenance and often increasing repair times when more hard breaks occur. In the case of the F-16, operational usage had been more severe than design usage (eight times more), resulting in the acceleration of its airframe service life at a rate that may not let it reach its expected overall service life.
Also at this point in history, the fate of its next generation stealth combat aircraft, the F-22 and F-35, hung in the balance. It, therefore, became politically expedient to highlight pessimistic projections about the future prospects of the USAF F-16 fleet.
Fast forward to the present day. The F-22 production line is complete, but with fewer aircraft than originally projected. F-35 development is moving ahead, but slowly. Faced with the prospect of reduced capability as a result of the latter aircraft’s delays, the USAF re-evaluated it fleet again, and came to the following conclusions which were published in Aviation Week magazine.
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However, the U.S. Air Force, which operates more than 1,000 F-16s of varying blocks, has no plans to procure more F-16s. Rather, the service is exploring options to extend the life of its fleet until the F-35 is introduced into service in enough numbers to handle the suppression and destruction of enemy air defense roles.
Originally designed for 4,500 flying hours, a previous upgrade extended the lifespan to 8,000 hr. But after conducting a monitoring program on the fleet, Air Force officials have found that they are flying the aircraft 15-20% “less hard” than planned, meaning pilots are not flying the jets to their maximum limits regarding such elements as speed or g-forces. This is partly because in the decade since the 9/11 terrorist attacks, the F-16s have been used largely to support ground forces or patrol the skies in permissive airspace, missions that do not require the taxing maneuvers seen while operating in hostile environments, says Maj. Luther Cross, F-16 program element monitor for Air Combat Command.
This has prompted the Air Force to calculate what officials call equivalent flying hours for each airframe, just as they do actual flying hours. Using the equivalent-hour metric, service officials are able to estimate the projected life, taking into account lighter use of the fleet in recent years, says Cross. This practice is also being applied to other fleets in the service.
This alone adds “several years” of life to each aircraft, he says. Still, the Air Force is considering a structural service life extension program (SLEP) to the newest Block 40/50 F-16s, with a 12,000-hr. goal per airframe.
The prospects for the availablity of suitable aircraft for the PAF’s needs, therefore, are not as bleak as the earlier GlobalSecurity.org would have pictured.
This article was also published on the following FaceBook group: F-16s for the Philippine Air Force
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