Ramon Lopez/WASHINGTON DC

THE US AIR FORCE should stockpile more spare parts for the Lockheed Martin C-5 Galaxy military transport and give priority to increasing its availability rate, according to a new report from the US General Accounting Office (GAO).

The USAF operates about 100 C-5As and C-5Bs and, although the Galaxy fleet is a key part of the Pentagon's airlift capability, its mission-capability rates have generally been below Air Mobility Command's (AMC) 75% mission-completion goal over the last few years, and considerably below those of the Lockheed Martin C-141, the McDonnell Douglas KC-10 and the Boeing KC-135, according to the Congressional investigation arm.

The GAO says that the USAF should improve spare-parts support and conduct a readiness evaluation similar to the one recently completed for the Rockwell B-1B bomber - an evaluation which showed that mission-capable rates could be increased if spare-parts support improved.

"The Air Force has not prioritised proposed C-5 modifications according to which ones would contribute to improving mission capability," the report concludes. AMC gives engine improvements and the replacement of the Galaxy's autopilot as the top priorities, while leaving the updating of hydraulic valves at the bottom of the improvements list.

The GAO, however, believes that hydraulic-valve replacement holds the most potential for increasing the aircraft's mission-capability. "Failures associated with the C-5's hydraulic system are one of the leading causes of reliability problems," the report states. It is estimated that hydraulic-system failures would decrease by up to 75% if the low-cost valve modification were completed.

If peacetime C-5 mission-capable rates could be raised to the current AMC goal of 75%, the Pentagon could gain an additional 4.8 million tonne kilometres a day of C-5 war-time airlift capability - the equivalent to that of ten McDonnell Douglas C-17 transports, the GAO says.

Source: Flight International