It is a new world in military maintenance, or at least it is trying to be. Technologies are changing as a new generation of military aircraft comes on line and as manufacturers develop an even newer generation. The fighters and other platforms of the future will be much smarter, more reliable and much easier to keep on the flight line, if plans work out.

Meanwhile, mature planes need to keep flying. These senior jets are getting older, a bit rustier and much more complicated to maintain. And many will remain in service for quite a while, at least through 2010.

During the transition, defense planners and maintainers are adding acronyms like PPP (public private partnerships) and PBL (performance based logistics) to their toolkits, along with phrases like "flexible sustainment" and "autonomous logistics." They represent a new way of running the military repair business, of doing things faster, better and cheaper.

The stakes are large. The Logistics Management Institute (LMI), a nonprofit consulting organization specializing in improving government management, estimates that the U.S. military spends $20 billion each year on maintenance and parts for its aircraft, at all levels from field to depot. Depot-level heavy maintenance costs $8 billion, roughly half of which is done by the private sector, the rest is completed by government facilities. Private firms do much less field maintenance, but they provide the parts used in field repairs.

Rust And Riddles

The biggest challenge in maintaining older aircraft is corrosion. A government-sponsored study estimated that corrosion costs the Defense Department $20 billion a year, counting all the Pentagon's assets. Aircraft corrosion is only a part of that bill, but it worries the experts. Aging systems, such as the 40-year-old KC-135, require increasing maintenance just to preserve their structural integrity.

Spare parts are the other major headache. "Many parts are no longer manufactured, and depots have to find someone to make them," said Dennis Wightman, LMI program manager for maintenance analysis. "Or depots must manufacture parts, such as floorboards." LMI estimates that materials have grown from 30% of depot costs to 40% in recent years. And engineering is becoming more important during each depot visit.

One way to save on maintenance is to predict failures through sophisticated diagnostic and prognostic systems. But that may require installing sensors. Technology is available for retrofitting older aircraft, but Wightman said "it is tough to make the business case for installing it."

Moreover, the best diagnostic and prognostic systems make use of at least three kinds of data: performance data, maintenance data and data on usage, such as cycles and flight hours. Link Jaw, CEO of Scientific Monitoring Inc. (SMI), which provides IT for engine condition monitoring and maintenance planning, notes a further problem. Even when all the data is available, it is formatted in different ways and may be stored in different locations. "To do a robust analysis, the performance data must be tied to maintenance data and usage data," Jaw said.

So aging aircraft require much more maintenance, and it is often very hard to predict how much they will need.