Wings do many things. Their first purpose, of course, is to
provide aerodynamic lift to get the aircraft off the ground; but
they also carry heavy engines, bombs, and fuel pods. Still
others carry undersigned-for external ordnance. One other common
thing these all important wings do is get tired and fatigued and
many times they develop dangerous cracks. Sometimes it happens
much sooner than predicted. The Air Force has examples of each
type. The first is the venerable 15- to 20-year-old B-52 and,
surprisingly the relatively new C-5A. The oldest of the giant
eight-engined bombers still flying, the B-52D, was one of the
most numerous of the giant Stratofortresses built. Extensively
used in Vietnam, many of these late 1950s versions were sporting
well over10,000 flight hours although they were originally
designed for only half that number. In 1971, the planned phase-
out year for the D-birds, the Air Force decided that the
aircraft would be needed much longer. But something had to be
done--and in a hurry, since t