Wear and tear adds up on military aircraft

New F-22 and F-35 fighter aircraft are coming onstream, but the Air Force and Navy will be flying many 20-to-50-year-old planes for the foreseeable future.

The gleaming icon of American military supremacy is the jet fighter, streamlined and lethal as it shrieks through the sky. On November 2, 2007, one of those fighters broke into pieces in the air. The pilot ejected safely, but the Air Force grounded an entire class of aircraft -- 441 A/B and C/D models of the F-15 Eagle air superiority fighter -- for most of two months. Training flights were canceled, homeland-security patrols were transferred to other aircraft, and pilots were stuck on the ground in simulators while maintenance crews conducted a series of frenzied inspections.

"There were daily conference calls with the accident investigation board," said Maj. Joe Harris, commander of the Air National Guard's 142nd Aircraft Maintenance Squadron in Portland, Ore. "We were released to fly, and then they grounded us again." Getting their base's 20 F-15s back in the air took Harris's mechanics "over 5,000 hours" of work, he said -- 250 hours per plane.

The problem: A key structural element in many early F-15s -- including six of the 20 at Harris's base -- had been manufactured too thin and thus did not conform to specifications. The defect was so slight that no one noticed for two decades. But the F-15 that cracked up in flight had been in continuous service for 27 years. That translated into 5,600 flight hours, thousands of jarring takeoffs and landings, and countless high g-force turns. The wear and tear had simply added up. The average age of the 441 grounded F-15s? Twenty-five and a half.

Those F-15s are not alone. The average age of the Air Force's core fighter, the F-16, is 16.7 years. The average age of the Navy's F-18 is a relatively youthful 13.6 because the Navy bought more fighters in the 1990s than the Air Force did. Both services, nevertheless, are relying primarily on fighters built during President Reagan's defense buildup. Even the military's own notoriously optimistic budget projections call for buying new planes at such high prices -- and therefore at such low annual rates of production -- that some 1980s-vintage aircraft will have to stay in service through the 2020s, when they will be more than 40 years old.

Large-bodied aircraft tend to last longer than hard-maneuvering fighters, but many of the military's big planes date back to President Kennedy's buildup. The average age of the B-52 bomber is 46.6 years, older than most of its pilots. The KC-135 tanker that both the Air Force and Navy rely on to refuel other planes of every type in-flight? Depending on the model, it averages 46 to 48 years old.

On February 29, the Air Force awarded a long-delayed contract for a replacement tanker to a consortium of Northrop Grumman and EADS, the defense arm of Europe's Airbus. The losing bidder, Boeing, has filed a formal protest. Even if the program proceeds on schedule, the last KC-135s may not be replaced until they are 80 years old. "These airplanes could fly as late as 2045," said Ben Robinson, a retired brigadier general who now heads the plane's maintenance program at Boeing. "The last crews, their parents haven't met each other yet."

Costs Per Flight-Hour Rising

To be sure, over the past two decades, the armed services have invested billions of dollars in modernizing, upgrading, and extending the working lives of their 1980s-vintage aircraft. But they cannot just pop out old, tired parts and snap in new ones: The process is more like pulling one strand on a sweater and hoping that the whole thing doesn't unravel. To repair the F-15s, for example, mechanics had to peel back the aircraft's steel skin and pull off its ribs just to get at the faulty part (a longeron), and then put everything back together. By one estimate, replacing the $12,000 part cost $250,000 in labor.

Swapping out a more complex component can cost millions. The 1960s-vintage KC-135 tankers, for example, later acquired more-powerful, fuel-efficient engines. "You've got a more powerful engine, therefore you've got to have a stronger engine strut that connects the motor to the wing," Boeing's Robinson explained. "You need different hydraulic pumps because the hydraulic pumps are driven off the engines. You've got a more powerful airplane, and the rudder needs to be more efficient. In the cockpit itself, all of those engine instruments had to be updated." The aircraft even got new aluminum skin on their underbellies, Robinson said, because "there's a lot of corrosion right below where the restroom was."

Once in place, the new parts break down less often -- not just because they undergo less wear and tear but because maintenance crews are replacing mechanical or hydraulic moving parts with solid-state electronics. But the high-tech components require a higher degree of skill from the mechanics. "What they're doing is more complex, and the demands placed on them continue to increase," Harris said. "It's tougher and tougher to recruit into those career fields."

Between new complexities and old parts, it takes more work to keep fewer planes less ready. "In my 10 years with the F-15, the cost per flying hour has doubled," Harris said. In fact, the cost per flight hour has climbed for every one of the 14 major aircraft types in continuous service since the 1980s (a trend aggravated by rising oil prices). All 14 have lower readiness rates than they did in 1991.

Many aircraft have to be flown at less than their design limits. "We've placed restrictions on them to preserve the structural life of the airplane," said Maj. Gen. Paul Selva, director of strategic planning for the Air Force. But engineers and maintainers can guard against future problems only to a certain extent. Last November's F-15 crackup was only the latest ugly surprise. The younger and more numerous F-16s suffered a series of crashes, traced to engine faults, in the late 1990s; and 63 F-16s are currently grounded with structural cracks. A KC-135 crashed in 1999 because of a failure in its flight controls. "We're essentially conducting a grand experiment," Selva said. "We've operated most of the airplanes we're flying beyond their originally designed life span."

At some point, the military needs to start buying new aircraft to replace those built when Reagan was in office. But after the Cold War ended, Presidents George H.W. Bush and Clinton cut the military procurement budgets sharply even as the price of new higher-tech aircraft continued to escalate. Crunched between shrinking budgets and rising costs, the Navy and the Air Force made very different decisions -- not only on how many planes they bought but also on what kind of wars they bought planes for.

The Tortoise and the Hare

In the heady days of the 1980s, the Air Force and Navy moved on parallel tracks. Both bought hundreds of short-range, high-performance fighters and struggled to develop longer-range, larger-payload bombers designed to evade enemy radar, specifically the Air Force B-2 and the Navy A-12. When procurement budgets shrank, the same roof fell on both services. Fighter procurement dropped from a peak of 399 in 1986 to just 60 in 1993, the B-2 was cut back from a planned 132 planes to just 21, and Defense Secretary Dick Cheney canceled the A-12 altogether.

The Navy decided it could no longer wait for the development of stealth airplanes, with their ungainly radar-diffusing shapes, which made them difficult to land on aircraft carriers, and their radar-absorbent coatings, which made them difficult to maintain in salty sea air. Instead, Navy planners focused their modernization program on a heavily upgraded F/A-18E/F Super Hornet, a plane 30 percent larger -- and correspondingly more expensive -- than the basic F-18, and able to carry more bombs and fuel but still lacking the range, payload, or stealth envisaged for the canceled A-12.

The Air Force, by contrast, bet all of its chips on stealth. Disappointed by the handling and maintenance problems of its F-117 stealth fighter and B-2 stealth bomber, the service invested heavily in a "third generation" of stealth that would combine radar-evasion with high-agility aerodynamics, supersonic speed, and manageable maintenance. While it poured ever more billions of dollars into this Holy Grail fighter, the F-22 Raptor, the Air Force all but stopped buying more F-15 Eagles and F-16 Falcons.

The two services' purchasing profiles diverged dramatically. Navy fighter procurement plunged from 171 planes in 1986 to just 36 planes in 1993, and then grew to a steady current rate of 40 to 50 F/A-18s of various types per year. The average age of its fighter fleet rose, but only from 11 years in 1986 to 13.6 today.

By contrast, Air Force fighter procurement crashed to the ground: 228 planes in 1986, 24 in 1993, zero in 1995. Purchases did not climb back up to 21 planes a year until 2003 -- but all 21 were F-22s, in service at last. In the meantime, however, the average age of Air Force fighters has climbed from less than 11 years in 1986 to more than 20 today. What's more, the F-22s cost so much to build -- $122 million to $180 million apiece, not counting the two decades of R&D expenses -- that the Air Force budget cannot buy enough to replace its 1980s-vintage aircraft plane for plane.

Sticker-shocked administration budgeteers have slashed the F-22 planned buy to 183 aircraft. Air Force generals have insisted they need 381 -- enough to have two full squadrons of 24 F-22s ready to deploy abroad at any given moment and eight more squadrons either recovering from deployment or gearing up to go, plus trainers, test planes, and spares in case of crashes. One Hill staffer told National Journal that the Air Force's clamor for more F-22s had escalated into "open warfare" between the generals and their civilian superiors in the Office of the Secretary of Defense.

"We have had a couple of people get way off the reservation and say, 'It doesn't matter what the Congress and the secretary of Defense say, we're going to buy the [381] airplanes,' " admitted one senior Air Force official who declined to be named. The Air Force has to at least get one point across, the official said: "If you can't support us on 381, don't make a premature decision to close the production line, because if you close the line, you've forestalled any other options."

Current spending plans punt this decision by funding neither continued production nor the shutdown of production facilities. Congress is likely to insert more F-22s into the defense budget. But even the Air Force's dreamed-of 381 planes, bought at the current rate of 20 planes a year, will not replace its 441 F-15s for decades. "They still plan to keep 177 of the F-15C/D version through 2025, some of them by then 40, 45 years old," said Mark Bass, the Boeing executive in charge of sustaining and modernizing the F-15s. "That is based on the Air Force eventually procuring 381 F-22s." And what if they don't get 381? "They don't have that in their plan," he said.

Lightning Strikes

Some relief arrives for the Air Force in 2013, in the form of its first squadron of the F-35 Lightning. Conceived in the 1990s as the Joint Strike Fighter and imposed by the Defense Department on reluctant Air Force generals and Navy admirals, the F-35 is intended to be cheap enough that the two services, combined, can buy 2,443 in three variants. Meeting that cost target has meant sacrificing some of the high-performance attributes of the F-22, especially its supersonic dogfighting capabilities, and focusing the F-35 on more-prosaic ground-attack missions.

"You had to sacrifice some of the total dominance in some of these mission areas," said Maj. Gen. Charles Davis, the Air Force officer in charge of the joint service program. As for the price targets, "since the contract was signed back in 2001, the cost of the airplane has risen about 38 percent," mostly because of the rising price of specialty metals on the global market. "Within factors we can control, we're doing a pretty good job," Davis said. "Is it ever going to be the $39 million aircraft [proposed in the '90s]? No. That was probably unrealistic."

If the F-35 materializes more or less on cost and on schedule, it will be the plane the Air Force relies on to replace its 1,200 F-16s and the Navy relies on to replace about 1,000 early-model F-18s. By 2030, the Air Force will at last have the all-stealthy fighter force it dreamed of in the 1990s. Both the F-22 and F-35 are designed to avoid detection: Their shapes minimize radar reflections, their engines hide the heat of the exhaust, and their weapons stay concealed until launch. But the Navy intends to fly its F-35 variant alongside its F/A-18E/F Super Hornets, which, despite some "low-observable" features, have to carry their bombs and missiles dangling from the wings, a dead giveaway on radar.

Instead of stealth, the Navy plans to use high-powered jammers to baffle enemy radar. It is investing in an "electronic attack" version of the Super Hornet, the EA-18G Growler, to replace the 1970s-vintage EA-6B Prowlers used today. The Air Force, by contrast, retired its electronic attack aircraft years ago and is relying on Navy jammers while it waits for its all-stealth fleet.

"The Air Force does not believe that aircraft lacking stealth will be able to survive in the future," said Loren Thompson, a defense-industry consultant and analyst at the Lexington Institute who has close ties to Air Force officials. The Soviet Union collapsed before Moscow could build the interlocking system of advanced Sukhoi fighters and long-range surface-to-air missiles that the F-22 was designed to defeat. But Russia's cash-strapped defense industry has sold some of its technologies abroad, allowing China, in particular, to raise the risks for any nonstealth aircraft operating within a few hundred miles of its territory. As Sukhois and SAMs proliferate, Thompson said, "the Air Force doesn't understand why the Navy doesn't feel a greater sense of urgency about moving beyond the existing Super Hornet."

Navy Capt. Mark Darrah, chief of fighter modernization for the Naval Air Systems Command, acknowledges that the Super Hornet is not stealthy. "We know that," he said, but "when we look at survivability, it's a multifaced issue, and the observability of an airplane is just one aspect."

The Navy's problem with stealth is Moore's Law, referring to the rapid improvement in computer chips. Because stealth has to be built into the basic structure of an aircraft, the degree to which a plane reflects radar beams back to enemy receivers remains essentially the same throughout its 20-plus years in service. The computing power available to those radar receivers to distinguish faint signals from background noise, however, doubles every 18 months. "Signal processors are getting faster all the time," said Norman Friedman, a military analyst and historian who is a leading critic of stealth. "There may be some reason to believe Moore's Law is going to top out, but how much money do you want to bet on that?"

The Air Force's problem with jammers is that by definition they emit energy. If the jamming does not blind the enemy, it gives away your location instead. The F-22 and F-35 will actually have significant electronic warfare capacity built in, but as long as their jammers are on, their stealth is effectively off. Still, F-22 and F-35 pilots will at least have a choice between passive stealth and active jamming; their Super Hornet colleagues have jamming, or nothing.

At best, the Air Force and the Navy will end up with two very different but complementary fighter fleets, each optimal for a different kind of enemy, each a hedge against the failures of the other. At worst, neither will be able to afford enough planes for its chosen approach to work at all.