December 17 will mark the 40th anniversary of the day in 1969 when the first C-5 Galaxy cargo plane was delivered to the U.S. Air Force. In some quarters that milestone might be cause for celebration, but in the current congressional debate of airlift options, the longevity of the C-5 is being cited as a problem. Proponents of buying more C-17s — the only strategic airlifter still in production in the United States — argue it would be a mistake to end production when the 111 C-5s in the fleet are so old. Some C-17 supporters believe that aging C-5s should be retired to make room in the budget for more C-17s.
There are good reasons for buying more C-17s before the factory shuts, but the age of C-5s isn’t one of them. First, the 77 C-5As built between 1969 and 1973 all were fitted with new wings in the 1980s, which greatly extended their structural lives. Second, 50 new C-5Bs were produced between 1986 and 1989. Third, all 111 C-5s in the fleet are being equipped with new digital electronics under a program that began in 1998. Fourth, a Reliability Enhancement and Reengining Program is demonstrating that the introduction of new General Electric engines and other improvements can substantially bolster the performance of the planes. Finally, both the “A” and the “B” versions of the plane were designed to operate under much more demanding conditions than they typically are exposed to — like landing on unpaved surfaces — so their projected service lives are much longer than the nominal design life of 30,000 flight hours.
Thus, despite its long history in the fleet, the C-5 isn’t really that old in terms of wear and tear. Even if the design life were treated as a deadline for retirement (something that almost never happens with military aircraft), C-5s would still have decades of service ahead of them because the typical Galaxy has logged less than 20,000 flight hours under circumstances far more benign than originally anticipated. A fleet assessment in 2004 identified no major structural issues, and a subsequent destructive inspection that tore down the plane to uncover hidden problems confirmed the airframe was sound. This probably is due in part to the fact that the C-5 was the first airframe the Air Force bought designed to be highly resistant to corrosion. As a result, the two biggest enemies of airframe longevity — metal fatigue and corrosion — are not major concerns in the C-5 fleet today.
Some critics have pointed to the relatively low mission-capable rate of older C-5s to argue that age has begun to take a toll. However, the real culprit in C-5 readiness is Air Force spending priorities. The 77 “A” variants of the C-5 are assigned to the Air Force Reserve and Air National Guard, which often are deprived of adequate funding for spare parts and maintenance manning. Thus, planes take longer to rejoin the fleet when they are sent into shops for routine maintenance, which reduces their availability. But the bottom line on the C-5 fleet is that it can easily remain active in the airlift role beyond the year 2040, and with new engines it can perform better than ever before — using less fuel and shorter runways to carry more cargo on longer flights. Since each C-5 can already carry 50 more tons per flight than a C-17, it makes little sense to retire Galaxies anytime soon.
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