Over 2,000 F-16s are undergoing a structural modification
program that will enable the aircraft to fly their planned 8,000
hours, rather than only about 6,000. Each kit contains new parts
and tools and costs about $500,000, and takes several months to
apply. The fix consists of reinforcing or replacing many
internal structural elements of the aircraft. There will be over
40 variations on the basic kit, to accommodate the many
different models of the F-16. It will take about nine years to
apply the kits to all aircraft that need them. Fixes like this
are common with combat aircraft. When the initial design and
testing of a military airplane is done, a lot of assumptions
have to be made about exactly how the aircraft will be used.
Tactics, and weapons carried can change over the 20-30 year life
of an aircraft. This will change the kinds of stress put on the
aircraft structure. This results in some parts of the aircraft
wearing out earlier than expected. This can shorten the useful
life of the aircraft, reducing