U.S. Navy Struggles to Keep its aging Aircraft Fleet Flying.

As wave after wave of combat aircraft roar off the decks of U.S. carriers in the Arabian Sea to attack targets in Afghanistan, the Navy and Marine Corps are wrestling with the increasing age of their air fleets.

The average Navy airplane is now 18 years old, Defense Secretary Donald

"For the first time, our average aircraft age exceeds the average age of our combatant ships," said Adm. William J. Fallon, vice chief of naval operations.

Most Marine helicopters are more than 25 years old, said the corps' assistant commandant, Gen. Michael J. Williams. "Some of our younger pilots are flying the exact same aircraft that their fathers flew."

The reason for this increasing age, Rumsfeld explained, is that the two services have not been able to buy enough new planes every year. He cited this example: To maintain its required 4,200 aircraft at an average age of 18 years, "the Navy needs 180 to 200 new aircraft per year at a cost of $11 billion."

The 2001 budget amendment, however, would provide 97 aircraft at a cost of $8.4 billion, Rumsfeld noted, and the 2002 budget would add 88 airplanes at a cost of $8.3 billion.

As the average age of the Navy's aviation force goes up, "there has been a corresponding increase in the costs of operations and maintenance," Fallon said. "Specifically, the cost of aviation depot-level repairables--which is driving the cost of maintaining our aircraft--has risen an average of 13.8 percent per year."

To help stem these costs--and to keep aircraft flying safely as long as possible--the Naval Air Systems Command in 1999 established an Aging Aircraft Integrated Product Team. The team, which is headquartered at the Patuxent River Naval Air Station, Md., has been assigned to spearhead efforts to improve readiness and reduce lifecycle costs for Navy and Marine Corps aircraft.

The team is pursuing a systems-engineering approach, said its leader, Robert P. Ernst. "1 don't have a large staff," he told National Defense. The team consists of 16 fulltime personnel, with others working part-time. It includes representatives from the major aircraft programs operated by the two services.

The focus of the team is to find new and better ways to counter the problems caused by age, Ernst explained. Chief among the targets are faulty wiring, corrosion and fatigue, he said.

The Biggest, Ugliest Dogs

"We're resource-limited," he said. "So we're going after the biggest, ugliest dogs first."

For example, the team has worked with the Office of Naval Research and the Federal Aviation Administration to develop an arc fault circuit breaker to protect military and civilian aircraft from problems caused by aged electrical wiring.

Modern aircraft have thousands of feet of such wiring, explained senior electrical engineer Charles H. Singer Jr. Over time, the insulation protecting that wiring degrades, he said. "In a building, insulation might last 100 years. In an airplane, it could wear out in maybe 10 or 15 years."

The wiring--and its insulation--can be damaged by extreme weather, moisture, fuels and the stress associated with flight and even routine maintenance, Singer said. About half of all Navy and Marine aircraft are equipped with old forms of aromatic polyimide insulation, which the Navy stopped installing in new combat aircraft in 1986 because of its poor are-tracking characteristics.

As this insulation ages, it is particularly susceptible to deterioration, cracking and flaking, Singer explained. This, in turn, can lead to arc faults and failure of the wire, creating a fire hazard.

"In one 30-month period, we documented 64 in-flight electrical fires," Singer said. The arc fault circuit breaker--which is similar to those used in residential homes, but smaller and much sturdier--is intended to help prevent such fires.

"The arc fault circuit breaker will detect a problem and keep it from killing you," said Singer.

Prototypes have been built by Eaton Aerospace, in Sarasota, Fla., and Hendry Telephone Co., of Santa Barbara, Calif. Flight tests began this summer aboard a Boeing 727 airliner supplied by the FAA and a Navy C-9 transport.

If all goes well, Singer said, a breaker will be available in the fall of 2003 for use in the 727, C-9 and Navy E-6 airborne command post. "Fighters and helicopters use a smaller breaker," he noted, and that should be available in 2006.

To speed up the process of finding and replacing aged wiring systems, NavAir is partnering with ONR, Management Sciences Inc. and Utah State University to develop "smart-wire" technology. Smart wiring involves the embedding of intelligence and sensors in wiring systems to monitor and manage the health of the systems, explained the program's head, Sean Field, an electrical engineer. Most Navy and Marine aircraft would benefit from such technology, which could be installed easily in existing aircraft, he said.

Up to 2 million man-hours per year are required at the organizational level to troubleshoot and repair aircraft wiring-system problems, Field said. Wiring troubleshooting and repair are still "hands-on" activities, which have changed very little in the past 40 years, he added.

"There is a pervasive need for an automated or semi-automated system for managing the health of the wiring system," Field said. Wiring systems should be managed in the same manner as avionics systems and engines.

The smart-wire system is intended to meet this need. It is meant "to detect, isolate and locate wiring faults quickly and expedite repairs on the flight line," Field said. It also "should capture and store, for future analysis, the in-situ condition of an aircraft wiring system's health on a tail-number basis." This, he said, would permit maintenance intervention before a wiring failure occurs.

A prototype smart-wire system is scheduled for completion in April 2002, Field said. The finished system is expected to be ready for the fleet in 2006.

Another enemy of Navy and Marine aircraft is corrosion. About two thirds of the strikes against targets in Afghanistan during the opening weeks of that campaign were conducted by carrier-based aircraft.

Maintaining aircraft aboard a carrier--where waves of seawater frequently wash over the deck and the very air is full of salt--is a constant battle against corrosion, said Ernst.

"Aircraft corrosion was a $1.4 billion problem for the Navy and Marine Corps last year," he noted. "By far, it's our largest single cost driver."

Corrosion in aircraft rakes many forms, said Kevin Kovaleski, organic coatings team leader. "There isn't any one goose with golden eggs that we can jump on," he said. "It rakes a lot of dirty fingernail work, and that's what we have been doing."

The team has been working with NavAir's Organic Coatings Laboratory, also located at Patuxent River, to develop a new spot corrosion kit to replace the older technology currently in use. The kit contains everything a technician needs to treat corrosion, including:

* Two radial bristle disks.

* A high-speed pneumatic grinder.

* An inspection mirror.

* A six-inch metal ruler.

* A six-inch, miniature flashlight.

* A pocket magnifier.

The disks, built by the 3M Corporation, are made of plastic containing aluminum oxide and a proprietary element that gives them a grit of 400, said Kovaleski. The disks currently in use "are way too abrasive," he noted, requiring more stripping and repainting than is necessary.

The new versions make it easier for maintainers to remove small areas of corrosion "before it gets out of hand," he explained. The disks also enable maintainers to strip less metal and reapply less paint, thus reducing maintenance costs.

The kits should be ready for distribution to the fleet beginning in late 2002, Kovaleski said.

NavAir engineers developed another kit to speed up the spot-paint repairs of aircraft, while reducing overall procurement and disposal costs, according to Navy spokesman John Milliman.

The centerpiece of this kit is a pencil-shaped product called SemPen, he said. Made by PRC-DeSoto, of Glendale, Calif., the SemPen is designed to store, mix and apply small quantities of two-component paints and primers. It is small enough to fit in a shirt pocket, like a pen.

Spot Painting

The SemPen enables maintainers to do small spot-paint repairs without the need to isolate the aircraft to protect nearby personnel from toxic fumes associated with large amounts of aerosols and spray paint. This enables other maintenance to be conducted at the same time as the spot painting, Milliman explained.

As aircraft grow older, it gets more and more difficult to keep them airworthy, said Laurence W. Stoll, head of integrated logistics and operations support.

"Eventually, you either have to buy new aircraft--and we can't afford to buy enough of them--or you have to do extensive work on your existing fleet," he said.

Structural fatigue is an increasing worry, said Paul C. Hoffman, head of the structures science and technology team. Military aircraft are required to withstand randomly occurring fatigue during their design service lives, he explained. Before the end of the Cold War, aircraft usually were replaced at the end of those service lives. Now, however, they are being kept in the fleet for much longer periods, and maintainers are seeing more fatigue problems--including visible cracks--than ever before, Hoffman said.

Because of relatively cramped quarters, carrier operations prohibit extensive inspections and repairs aboard ship, so when problems are detected the aircraft must be sent ashore for repairs, Hoffman explained.

For the older platforms, it gets progressively difficult to find spare parts or even repair manuals, Stoll pointed out. Production lines shut down. Companies go out of business or merge with other firms.

Ernst called it "defense Darwinism," an economic survival of the fittest." Some companies, he said, become larger and stronger, while others are consumed by the survivors, and still others become extinct.

"We usually get about six weeks' notice that somebody's no longer going to supply parts," he said.

Avionics--aircraft electronic systems--have been hit particularly hard by this trend, Ernst said. He gave this analogy:

"You probably replace your computer every two or three years. Our budgets cannot keep up with that kind of turn around." Avionics equipment is vastly more expensive than a personal computer.

Thus, he said, the avionics in older Navy and Marine aircraft is often old and under powered. And keeping it running is difficult. "Have you tried," Ernst asked, "to buy parts for a 286-chip computer lately? You don't go our and buy this stuff at Radio Shack."

The Navy is doing a better job of taking care of its aging aircraft, Ernst said, but it needs to do more. "If we put the tools out there, we can assess the life cycles of our aircraft and make good decisions about when to replace them," he said. "We're not there yet.

The Navy aging aircraft program needs to line up additional funding for testing, engineering, acquisition and logistical support, Ernst said. "It takes an enormous amount of work." He noted that he made 60 major presentations last year himself.

"It would be nice if we had a big pot of money out there that we could tap into, but we're doing guerrilla warfare," Ernst said.

"We need to ratchet this team up a level," he added. The Air Force has a similar program, he pointed our, and it is headed by a flag officer. "We need an equivalent."

Ernst is a civilian employee of the Navy, but he joked: "I have to earn my wings every day."