Major military equipment is purchased with the expectation – as part of the development and acquisition contract requirements – that it will have a useful life of one or more decades. The larger and more expensive the item, the longer its lifespan; for aircraft, that tends to be in the 20- to 30-year range, although many airframes have remained in active use far longer (the B-52 bomber, for example, is still flying missions, although the “newest” was built in 1962).

A key element in determining the useful life of equipment is how it is expected to be used – how many training exercises, how many combat missions, etc. From the end of major combat in Vietnam in 1973 until Sept. 11, 2001, most equipment rarely, if ever, saw combat; for those that did, it was of short duration. As a result, the vast majority not only met but often significantly exceeded useful life requirements.

A decade of nonstop combat operations in Southwest Asia has dramatically altered that equation on land, in the air, and at sea.

A July 2010 review of the Department of Defense’s Quadrennial Defense Review (QDR) by a congressionally mandated independent panel – co-chaired by former President George W. Bush’s national security adviser, Stephen J. Hadley, and former President Bill Clinton’s secretary of Defense, William J. Perry – found problems with the Obama administration’s plans for the U.S. military, particularly with respect to the Navy.

“The aging of the inventories and equipment used by the services, the decline in the size of the Navy, escalating personnel entitlements, increased overhead and procurement costs, and the growing stress on the force means that a train wreck is coming in the areas of personnel, acquisition, and force structure,” Hadley and Perry told the House Armed Services Committee (HASC) on July 29, 2010.

For aviation, among the most significantly affected by nearly a decade of war – on the heels of a decade of multiple U.S. military engagements around the globe – has been the C-17 Globemaster III cargo/transport jet, which entered service in 1993 to carry troops and outsized cargo to and from short, austere airfields.

Originally designed for a 30-year operational life, based on 1,000 flight hours per year, the U.S. Air Force (USAF) fleet is well above that average. Nearly continuous transport operations for Iraq and Afghanistan were responsible for the worldwide fleet hitting a milestone of 1 million flight hours in March 2006 – then doubling that to 2 million by December 2010.

That first milestone led the Air Force to request $1.6 billion in FY 2007 to deal with what it termed “excessive combat use” on its operational airframes – fewer than 150 C-17s at the time.

As of November 2010, prime contractor Boeing had delivered 203 aircraft to the USAF, with approved funding for an additional 20. However, Defense Secretary Robert M. Gates has ordered production for the USAF to end at 223, once those now funded are completed in 2012.

While U.S. air superiority has not been seriously challenged since Vietnam, the nation’s legacy aircraft have been employed in numerous combat operations over the Balkans, Libya, Iraq, and Afghanistan in the past 20 years. The vast majority have reached or are approaching 30 years since first entering service. All essentially are scheduled to be replaced by two fifth-generation platforms – the F-22 Raptor stealth fighter, operated exclusively by the USAF, and the F-35A/B/C Lightning II Joint Strike Fighter, for the fleets of the U.S. Air Force, Marine Corps, and Navy, as well as eight international program partners and a variety of other allied air forces.

With Gates ensuring that the Raptor program will end with only 187 of an original planned buy of 650, the aircraft it was to replace – primarily the F-15C/D Eagle, produced from 1979-85 – is being upgraded with advanced technology systems, such as the Active Electronically Scanned Array (AESA) radar, Joint Helmet Mounted Cueing System (JHMCS), and Infrared Search and Track (IRST). With those and a service life extension program, the older Eagles now are expected to remain in service at least until 2025, with the newer, more advanced F-15E Strike Eagle (1985-2001) continuing well beyond that date.

The only other fifth-generation fighter in production, the F-35, is scheduled to reach initial operating capability (IOC) with the U.S. Marine Corps in 2014 with a short takeoff/vertical landing variant (F-35B). Air Force officials have said that service’s F-35A IOC may slip to 2016, while the Navy still hopes for F-35C IOC by 2014. With production of some 2,400 U.S. aircraft across the three variants through 2036, the F-35 is intended to supplement the F-22 while replacing all remaining U.S. military combat aircraft – USAF F-16 Fighting Falcon and A-10 Thunderbolt, Marine AV-8B Harrier II, and Navy/Marine F/A-18 “Legacy” Hornet.

Given the same cost and performance issues that plague any new aircraft – and a long history of dramatic reductions in ultimate procurement numbers – the aircraft the F-35 replaces will be called upon to remain in service considerably longer than the standard 30 years. As a result, upgrades such as those under way on the F-15 seek to extend the life and capabilities of those platforms.

The F/A-18A-D (1980-2000) has undergone a number of upgrades, including two recent and major reincarnations: The F/A-18E/F Super Hornet, classified as a Gen-4.5 fighter, and the EA-18G Growler, an electronic warfare version of the Super Hornet. While the F-35B/C variants are intended to replace both U.S. Navy and Marine Corps Hornets, the Super Hornet – which first entered service with the Navy in 1999 and has been replacing the F-14 Tomcat since 2006 – could remain in service for several decades.

In September 2010, the Navy signed a multiyear contract for 66 additional Super Hornets and 58 Growlers, in part to cover delays in the F-35 program. There also have been discussions of a further upgrade to a “Gen-4.75” version that could keep Hornets in service even longer.

While one of the older legacy aircraft still in service, since 1979, the F-16 is still in production, with foreign orders through 2012. The current schedule calls for it to remain in service with the USAF until 2025, gradually being replaced by the F-35A.

The A-10A entered service in 1975, providing close air support (CAS) to ground troops, but a newly modified precision engagement version – the A-10C – became operational in 2007. Upgrading legacy A-10s to A-10Cs includes upgraded cockpit displays, moving map display, hands-on throttle and stick, digital stores management, LITENING and Sniper advanced targeting pod integration, situational awareness data link, variable message format, GPS-guided weapons, and upgraded DC power.

While other aircraft, primarily upgraded legacy F/A-18s and future F-35As, will be available to handle CAS missions, the cost and low-altitude vulnerability of both significantly exceeds that of the venerable “Warthog.” With ground warfare expected to remain the centerpiece of any future combat, the odds are the A-10C and possibly further upgrades will remain part of the active fleet at least through the currently scheduled end of F-35 production in 2036.

Another aging fleet the Air Force has been trying to replace is its airborne tankers – 59 KC-10 Extenders (1979-87) and 530 smaller KC-135 Stratotankers (1954-65). A proposal to lease, then buy, a proposed Boeing KC-767 was killed in 2005, leading to a request for proposal (RFP) for 179 new tankers. A contract for the KC-X was awarded to a joint Northrop Grumman/EADS team for the KC-30B, an Airbus 330-based tanker, but was reversed on a protest from Boeing. A subsequent rebid was canceled in 2008; a new RFP was issued in 2009, but without a bid from Northrop Grumman. A decision on bids from Boeing and EADS has been repeatedly delayed, most recently until early 2011.

The aging U.S. helicopter fleet also has seen extensive use in the past two decades, beginning with the first Gulf War in 1990-91, through operations in the Balkans, Somalia, and the “no-fly” zone over northern Iraq to daily flights for nearly a decade in Southwest Asia.

An attempt by the Army to replace its rotorcraft – many dating back to the Vietnam War – has not gone well. The Marines have made the most progress with regard to capability by finally getting the controversial V-22 Osprey tilt-rotor into service. Delays and program cancellations elsewhere continue to plague the Army and Navy, despite agreement on all fronts that, although including some still considered the most advanced in the world, replacement of the world’s largest helicopter fleet is necessary.

Production and upgrades continue on the Army’s AH-64 Apache, some 1,700 of which have been built since 1983 (first flight was in 1975), nearly two-thirds in service with 12 other nations. The newest version is the AH-64D Longbow Apache, an upgrade of the AH-64A. In October 2010, prime contractor Boeing reported the fleet had accumulated more than 2 million flight hours, including extensive combat operations in Southwest Asia.

The Air Force announced plans in March 2010 to acquire 112 new medium helicopters to replace its aging HH-60Gs. The Army’s UH-1 Iroquois are being replaced by the UH-72 Lakota and allowing UH-60s to be released for combat missions; the Marines are replacing the AH-1W Super Cobra with the AH-1Z Viper, the Sea Knight with the V-22, the CH-53D/E with a new CH-53K Super Stallion (beginning in 2015), and the Twin Huey with the UH-1Y Venom.

In a recent report, the Congressional Budget Office (CBO) estimated the procurement funding needs expressed by Army aviation alone could total $61 billion between 2010 and 2026. However, an October 2010 analysis by Frost & Sullivan highlighted the need to respond to the impact of post-9/11 military operations.

“The global war against terrorism will continue driving the rotorcraft market, especially in Afghanistan,” industry analyst Nathan Smith reported. “Higher helicopter usage, extreme operational conditions, an aging fleet, aircraft retirement and losses will be major drivers for this market in the long term.”

With the bulk of the Pentagon’s helicopter budget going to new procurement, upgrades, and maintenance on existing platforms – and indications of further consolidation of American manufacturers – some have warned the United States could lose its technological lead to aggressive foreign competitors, such as Europe’s Eurocopter and AgustaWestland. A 2009 report by the market analysis firm Forecast International warned European companies continue to push the research and development envelope, while their U.S. counterparts are being funded only to sustain the legacy fleet.

While U.S. military operations in Iraq have diminished significantly, those in Afghanistan have increased, keeping the pressure not only on helicopters and fixed-wing transports but on all major military equipment, including tanks, trucks, Humvees, etc. With budget cuts reducing the Pentagon’s ability to make new buys of existing equipment and cutting new programs – such as the Army’s Future Combat System (FCS) family of vehicles – maintenance and service life extension have become more important than ever.

The Abrams main battle tank, which saw extensive action in Iraq, is now being deployed with the U.S. Marines in Afghanistan. Field commanders have said the tanks will be used defensively rather than offensively, protecting warfighters moving against entrenched Taliban strongholds in southern Afghanistan. The number of tanks involved also will be significantly fewer than saw duty in Iraq.

Even so, both the Army and Marines are expected to continue heavier than usual field training with the Abrams, first delivered in 1980, and other primary combat platforms, exercising lessons learned from the past 10 years and developing new tactics, techniques, and procedures for potential future conflicts.

General Dynamics Land Systems has built more than 9,000 Abrams tanks for the U.S. Army and Marine Corps. As part of its effort to extend the Abrams, the Army has equipped hundreds of tanks with small on-board computer systems to monitor maintenance needs and expects to have those installed on the entire fleet within five to seven years. The condition-based maintenance system will monitor electric circuits, hydraulics, and transmission systems, enabling repairs and replacements much earlier than would be the case with a traditional maintenance inspection program.

The Army had planned to replace the Abrams with the FCS program’s XM1202 Mounted Combat System. Instead, design work is under way for an M1A3 Abrams, with an IOC target of 2017. The M1 and other combat vehicles also could be replaced by variants of the Brigade Combat Team Ground Combat Vehicle, one of the planned individual component replacements for FCS.

Even so, the Army expects the Abrams, with continued upgrades and life-extension efforts, to remain in service until mid-century.

While FCS was intended to replace all ground vehicles for the Army – and, by extension, the Marine Corps – the future of individual replacements for typically shorter-life and heavily utilized vehicles, from Humvees to trucks, is now in flux.

U.S. Army Vice Chief of Staff Gen. Peter W. Chiarelli has been urging Congress to move swiftly and decisively to meet the Army’s future needs, especially in light of the high use rate demanded by a two-front, decade-long war. As he explained to the House Armed Services Committee in July 2009, Army tanks have been rolling more than five times their programmed annual mileage and the truck fleet has seen some six times planned peacetime use. For trucks and Humvees, the resulting wear and tear has been further exacerbated by the addition of heavy armor kits to enhance force protection.

“This increased operational tempo shortens the useful life of our equipment and demands a much earlier and larger investment in depot maintenance than programmed for peacetime operations,” Chiarelli told lawmakers.

For the Humvee, Southwest Asia has been more than high use, however. The standard version – and its passengers – became all-too-frequent victims of the Iraqi and Afghan insurgents’ weapon of choice, the improvised explosive device (IED). Even adding additional armor – which significantly reduced the vehicle’s operational capabilities – and the introduction of a new armored version with a heavier chassis, failed the IED test.

The Marine Corps made an urgent request for a new platform, leading to the rapid development and fielding of the heavily armored mine resistant ambush protected (MRAP) vehicle. From IOC in November 2007 through the end of 2010, some 26,000 MRAPs will have been produced and fielded to Iraq and Afghanistan by the United States, about one-third of those a second-generation MRAP all-terrain vehicle. Production currently is scheduled to continue through 2012.

Although the MRAP evolved from their request and has been heavily used by them, the Marines see no use for it as part of their permanent inventory outside of Iraq and Afghanistan. Its size and weight make transport to theater difficult – especially for a fast-moving expeditionary force – and leave it unable to cross more than 70 percent of the world’s bridges.

Even so, the Marine Corps has taken the lessons of Southwest Asia and IEDs to heart in seeking a smaller, lighter – but still major blast-survivable – squad transport, logistics, and medical evacuation vehicle. The Corps also has questioned whether the Joint Light Tactical Vehicle (JLTV) now in development will fit its requirement for 5,500 replacements for existing Humvees.

In its 2010 report to Congress on tactical wheeled vehicles (TWVs), the Army cited a requirement for some 245,000 TWVs through 2025 (down from the current 260,000) – one-third in the JLTV class – while noting “finding the right balance and mix of TWVs requires the Army to continually assess and adjust investments.”

To meet the various needs of different combat scenarios – from traditional battlefields with defined “front lines” to the ongoing asymmetric counterinsurgency fight now under way in Southwest Asia – the report called for a family of new TWVs, designed from the start around a Long-Term Armor Strategy (LTAS). The LTAS would accommodate increasing levels of armor, as required by combat commanders to adjust protection as needed to meet threats as they evolve.

Current plans call for JLTV to meet three specific mission sets – Force Application (armament carriers), Battlespace Awareness (reconnaissance, command and control, general purpose mobility), and Focused Logistics (light cargo utility vehicles/shelter carrier/casualty evacuation).

The Army also will be looking to upgrade/replace its medium tactical vehicles (MTV – 2.5 to 10 tons) and heavy tactical vehicles (HTV – 10 to 40 tons).

“The Army of the next 15 years must adapt its TWV fleet to meet the threats of today and tomorrow, with reduced funding as compared to the past seven years. The Army will meet this challenge by balancing the quality, quantity and cost of its TWV fleet to meet its mission requirements and fiscal responsibilities,” the report concluded.

President Ronald Reagan, in rebuilding the U.S. military in the 1980s, sought a 600-ship Navy capable of ensuring all components of American naval power – aircraft carriers, submarines, cruisers, destroyers, etc. – were present at all times throughout the world. Three decades later, the Navy’s fleet is less than half the size Reagan envisioned and, while still the largest in the world – with battle tonnage exceeding that of the next 13 largest navies combined – it comprises the fewest vessels since 1916.

While individual numbers vary as ships retire from service or are commissioned, the current active-duty fleet consists of 286 ships and falling.

While the Navy has stated a requirement for 313 ships – 276 of which would be newly constructed through 2040 – the CBO has reported the cost for such an effort – between $16 billion (the Navy estimate) and $21 billion (the CBO estimate) a year for shipbuilding – is unsustainable.

In prepared testimony for the HASC in July 2010, a warning about the current and future state of the Navy fleet was issued by Adm. J.C. Harvey Jr., commander, U.S. Fleet Forces Command; Vice Adm. William Burke, deputy chief of Naval Operations for Fleet Readiness and Logistics; and Vice Adm. Kevin McCoy, commander, Naval Sea Systems Command. The current “high operational tempo, as a result of growing operational requirements, is consuming the fleet at higher-than-planned rates,” they told lawmakers, creating an institutional risk that is on the rise from “moderate to significant.”

While saying the Navy has responded quickly and decisively to demands placed upon it, from a decade of war in Southwest Asia to the Haiti earthquake relief effort at the start of 2010, the admirals also voiced concern that overall readiness trends are moving in the wrong direction. That is especially true for the surface force, they added, which was “leaned out” for the past two decades.

A Fleet Review Panel commissioned in September 2009 to investigate the causes of increasingly negative inspection reports found “reductions to ship manning, ship maintenance capability and capacity, training programs, maintenance funding and assessment and inspection programs – the cumulative impacts of cost-cutting decisions made over the last two decades – had begun to degrade Surface Force readiness and potentially shorten the expected service life of our ships.”

Their testimony came some six months after Eric J. Labs, the CBO’s senior analyst for naval forces and weapons, told the same HASC Subcommittee on Seapower and Expeditionary Forces that maintaining the $15 billion a year the Navy has averaged on shipbuilding the past 30 years not only would fail to increase the fleet to 313 ships, but actually would result in a reduction to only 237 ships by 2040.

Replacing 14 Ohio-class ballistic missile submarines (SSBNs), which will begin reaching the end of their service lives in the late 2020s, with 12 new SSBNs could cost about $85 billion, for example. CBO estimates that might be possible, along with the cost of the rest of the Navy proposal, only if the annual shipbuilding budget grows to $25 billion (in 2009 dollars).

“Sea-based ballistic missile defense, a relatively new mission for the Navy, could require a substantial commitment of resources. That commitment could make it difficult for the Navy to fund other ship programs. Average annual spending for surface combatants would have to rise by 80 percent – and spending for submarine construction would need to more than double – for the Navy to buy the major combat ships included in [its] 2009 plan,” Labs testified.

“During the 1980s, the Navy bought an average of 17.2 ships per year in pursuit of a 600-ship fleet. By the 2000s, that number had fallen to 6.0 ships a year. To sustain the steady-state fleet of 313 ships envisioned in the 2009 plan, however, the Navy would need to buy 8.9 ships per year, under an assumption that the ships had an average service life of 35 years. To compensate for earlier years in which the Navy bought fewer than 8.9 ships per year, the 2009 shipbuilding plan would purchase 9.9 ships each year to achieve and maintain a 313-ship fleet.”

One response to the shrinking numbers of Navy ships was the Littoral Combat Ship program, envisioned as a large number of low-end, austere combatants that would depend upon off-board sensors as force multipliers and would perform mine warfare, anti-submarine, and anti-surface warfare in the shallow waters of the world’s coastlines. However, the costs of both classes of ships skyrocketed, and it is hoped that a plan to begin procurement with 10 ships of each class will cut costs.

In addition to higher costs for labor and materials, reports from the CBO and the RAND Corp. agree each new generation of ship costs more than its predecessor because of significant improvements in capability from new systems and technologies in almost every aspect, from weapons to command and control.

The independent QDR panel summarized many of the problems facing the U.S. military’s aging equipment base in the wake of a decade of intense combat use. And while praising Gates for presenting “a solid framework for current military activities,” the panel also expressed major concerns about how well the QDR addressed those top issues.

“There is increased operational tempo for a force that is much smaller than it was during the years of the Cold War. In addition, the age of major military systems has increased within all the services, and that age has been magnified by wear and tear through intensified use. For example, the average age of Air Force tactical aircraft is more than 20 years and the average for Navy and Marine Corps tactical aircraft is more than 15 years. Surface ships, bombers and transport aircraft fleets are all aging, as are armored and mechanized forces,” the panel concluded. “The Department of Defense now faces the urgent need to recapitalize large parts of the force.

“The general trend has been to replace more with fewer, more capable systems. We are concerned that, beyond a certain point, quality cannot substitute for quantity. The increased capability of our ground forces has not reduced the need for boots on the ground in combat zones and the increased capability of our naval forces has not reduced the need for ships to demonstrate – in an unshrinking world – a U.S. presence abroad. We think it is time technology be used not to simply increase performance, as important as that is, but to dramatically drive down cost so that we can increase quantity – perhaps even with more than a one-for-one replacement of some systems.”

A Heritage Foundation assessment, while quoting from the panel’s report, was even more blunt in its assessment of the QDR, the state of the military, and what needs to be done to reverse the effects of 20 years of declining force structure even as demands on that force multiplied.

“Over the past two decades, the size of the U.S. armed forces has declined by one-third. Conversely, each major defense strategy since the early 1990s has emphasized new missions for the U.S. military without providing substantial additional resources. Strained, aging platforms have reached the point at which they cannot achieve desired mission outcomes,” the foundation’s report concluded.

“The men and women in the U.S. military are ‘operating at maximum operational tempo, wearing out people and equipment faster than expected, using the reserve component more than anticipated and stressing active duty personnel in all the military services.’ There is no quick fix to meeting full modernization requirements and it will ‘require a substantial and immediate additional investment that is sustained through the long term.’”

This article was first published in The Year in Defense, Winter 2011 Edition.