The F-35, Ready for Prime Time?

June 1, 2005

The past year has been a turbulent one for the huge Joint Strike Fighter project. Manufacturers began assembling the first flying F-35, making the transition from abstract design to well-defined aircraft. Then, however, program officials concluded that they needed to slow things down. Weight problems had cropped up. The design was seen to be immature.

A year ago, JSF officials were just beginning to come to terms with program shortcomings. (See “The F-35 Gets Real,” March 2004, p. 44.) It was during preparations for the critical design review (CDR) that “we really saw the performance [problems] … manifesting themselves,” said Rear Adm. Steven L. Enewold, JSF program director.

Indeed, Enewold and others concluded the aircraft was not ready for CDR.

An end of 2004 assessment by the contractor, Lockheed Martin, noted that the F-35 program is “the most complex fighter program ever undertaken.” As a result, it warned, “serious” problems can erupt “with remarkably short notice.”

The F-35 was overweight, with the worst offender being the short takeoff and vertical landing (STOVL) variant. It had surpassed its limit by a whopping 3,000 pounds.

Recognizing that complex fixes were required, the program office slammed on the brakes. Major events—critical design review, first flight, initial operational capability—all were delayed by one to two years.

Ruthless Weight Cuts

The contractors and program office assembled a weight reduction team and attacked the problem from several directions. Roughly 2,700 pounds was cut from the STOVL aircraft, and the “equivalent” of 600 additional pounds was eliminated by improving the propulsion system and increasing thrust. The STOVL weight savings trickled down to the other variants.

The end result, according to program officials, is that the three F-35 variants are again projected to meet all key performance parameters. Critical warfighting capabilities are still being met, and a realistic schedule is in place.

The Air Force will buy both the F-35A conventional takeoff and landing (CTOL) variant to replace its huge fleet of F-16s and the F-35B STOVL jump jet as a follow-on to the A-10 attack aircraft.

The Marine Corps is buying the F-35B to replace its fleet of old F/A-18 Hornets and AV-8 Harriers. The Navy will use the carrier-capable F-35C as the replacement for its older F/A-18.

Enewold said he is cautiously optimistic that the F-35 will arrive on time to meet DOD’s urgent need for new combat aircraft.

“We laid out a schedule for ourselves last June,” Enewold noted in an interview with Air Force Magazine. Since the program was restructured, F-35 development has stayed on schedule.

It had better. Three US armed services—not to mention foreign customers—are depending on the arrival of this airplane, and there is no more flexibility to accommodate delays.

Projected IOC for Marine Corps aircraft is 2012. For USAF and Navy fighters, the IOC year is 2013. These new dates mark a two-year postponement for the Marine Corps and Air Force and one year for the Navy. Enewold said his program office considers the new dates inviolable.

For the Marine Corps, timing is critical. The service long ago passed up the opportunity to acquire the new F/A-18E/F Super Hornet fighter and chose to wait for the more advanced JSF. It can’t afford a holdup. According to Enewold, the Corps wants to avoid having to pay for major structural rework to its F/A-18s or postpone planned retirement of its old Harriers.

The Air Force has not yet decided how many of each JSF type it will order. The service has “made no commitment” about how many of its 1,763 F-35s will be STOVL and how many conventional, said Enewold. As for the possible STOVL procurement, he said, “I’ve heard anything from 100 to … 500.”

To the Air Force, even the total quantity is in play. Gen. John P. Jumper, the Air Force Chief of Staff, said, “I think that we will see an overall decrease” in the planned procurement of F-35s. Because of JSF’s greater capabilities and expected reliability, he pointed out, it is probably not necessary to trade F-16s and A-10s on a “one-for-one” basis.

“Clearly the JSF will be vastly superior to the aircraft it replaces,” noted Maj. Gen. Donald J. Hoffman, Air Combat Command requirements director. ACC is currently evaluating the number of STOVL and CTOL F-35s needed for future operational requirements.

The most specific public estimate of Air Force needs came from the Government Accountability Office. In a March report, GAO wrote that ACC officials told them last December, “The Air Force is considering buying about 250 [STOVL] JSFs and about 1,300 [CTOL] JSFs. This would reduce the total number of [F-35s] to be acquired by 213.”

USAF Rebuffed

An Air Force move to trim F-35 purchases was rebuffed by senior Pentagon leaders last December. In the Fiscal 2006 budget drills, DOD left the JSF budget untouched even as it slashed funding for F/A-22 and C-130J aircraft.

Getting the F-35 is important for the Air Force but, as the IOC dates show, slightly less urgent than it is for the Marine Corps. All things considered, officials say that USAF’s legacy strike fighters are still in decent shape, buying the Air Force some time while the F-35 develops.

A-10s have been heavily tasked in Afghanistan and Iraq for more than two years. Thanks to attentive maintenance, and “with serious input from [the] users,” the health of the 22-year-old Warthog is good, said Maj. Gen. Elizabeth Ann Harrell, ACC director of maintenance and logistics.

F-16s have “different challenges,” Harrell noted. They fly more stressful profiles. ACC could “beef up the airframe,” she explained, but no one can calculate the long-term prospects for KC-135-type corrosion or similar problems.

USAF recently decided to upgrade every one of its 356 Warthogs to an A-10C configuration. This adds precision weapons capability, updated cockpits, and, in conjunction with A-10 structural upgrades, allows the service to buy STOVL F-35s later in the production run than it first thought would be required. The Air Force has structural and performance improvements planned for the F-16 as well.

Thus, the Air Force still has several years to sort out exactly how many F-35Bs it wants. Air Force-specific changes to the F-35 are considered “post-system design and development” changes, which will be made later in the program. This activity will lead to a STOVL in-service date of approximately 2014, a program official said.

The F-35 is expected to be vastly superior to both of the aircraft that it is replacing. Hoffman noted that this creates a delicate balancing act in planning future inventories.

On official charts of the Air Force fighter force, lines corresponding to yearly aircraft inventories make a steep decline for several years, bottom out and stay low for a while, and then turn back upward. This graphical depiction—a line high at either end, with a major depression in between—is referred to as the “fighter bathtub,” in that it resembles the curve of a bathtub. The Air Force is “trying to minimize the bathtub”—meaning, the shortage of fighters the service will suffer later this decade as F-16s begin to age out and before the F-35 is ready to replace them in bulk. With 10 rotating Air and Space Expeditionary Forces to equip, small fleets don’t “divide well,” said Hoffman.

The Needs of Foreign Partners

One of the F-35’s unique aspects is the massive amount of foreign participation in the program. The United Kingdom has a special role in the fighter’s development and has committed to buying 150 short takeoff and vertical landing variants for the Royal Air Force and Navy. Other international partners include Australia, Canada, Denmark, Italy, the Netherlands, Norway, and Turkey, and they are contributing various levels of manpower, money, and expertise to the program. In 2004, Singapore and Israel joined the program as “security cooperation participants.”

Rear Adm. Steven L. Enewold, Joint Strike Fighter program director, observed that recent program delays leave very little room for error for a couple of partner nations.

The British and Australians “are very dependent upon our success because they’ve already started planning … the actual retirement of some of their systems,” he said. “They’re counting desperately on us to fill their force structure,” so that geriatric British Harriers and Australian F-111s can be retired as planned.

The British are “in more critical shape than we are, frankly,” said Enewold. That nation has already committed to drawing down its Harrier force and retiring three aircraft carriers. Two new British carriers—designed with the F-35 in mind—are being built, but now the first of those will likely be completed before its aircraft are ready.

Australia, meanwhile, will start phasing out its F-111s around 2012. That nation is also looking for new fighters at the very beginning of the JSF production run.

This spring, the program began formal negotiations with the international partners to create international production and sustainment plans. “When you get into sustainment, every one of the international countries [has] aspirations of doing things in their own country,” Enewold noted. The program office will determine “what we think is the most economical, cost-effective plan.”

For example, three major F-35 repair facilities might be desirable—one each in the US, Europe, and the Pacific. This would ensure that F-35s do not have to return to the United States for engine overhauls and other maintenance that can be performed in-theater.

“Every country thinks that their country’s the right place to do that,” Enewold said. There is already a term for the nationalistic outcome that is the likely result: “pay to be different.”

If national aspirations get in the way of overall program efficiency, “we’ll have that discussion” later, Enewold said. The plan is to have a signed memorandum of understanding about international participation ready by the end of 2006.

No “Capabilities Gap”

Yet, people rarely talk about a fighter “capabilities gap,” because there probably isn’t one, Hoffman said. If analysts were to count the number of precision weapons USAF’s fighter fleet can deliver rather than the number of fighter “tails” on the ramps, the tally would not show the same sort of bathtub, he noted.

Enewold said it is no accident the F-35 earned DOD’s support once again late last year. The program had just shown the ability to work through its weight and design problems. Heading into the planned design review in the spring of 2004, the program was “very technically unstable,” Enewold said.

Since that time, progress has been made in overall design, engine testing, and assembly of flying aircraft. There are a “whole lot of things that seem to be coalescing now,” Enewold said. Without progress over the past year, “we would not have done very well” in the recent budget deliberations, he said.

The F-35 program has been helped politically by its sheer scope and magnitude. It is the largest acquisition program the Pentagon has ever known, with huge numbers of industrial connections. JSF will be a family of highly versatile aircraft. “We’re going to be darn good” at almost every fighter mission, Enewold said, “and the best overall.”

Because several different programs would be needed to replace JSF, the massive program is actually “probably the most cost-effective” way to meet a wide range of future warfighting needs, he said.

For the US Air Force, US Marine Corps, Royal Air Force, Royal Navy, and others that may buy the STOVL version of the F-35, there may be no realistic alternative.

The Air Force recently discovered that its A-10s were the only fighters that could operate from many of the short and rough airfields in and around Afghanistan, said USAF Brig. Gen. (sel.) Charles R. Davis, JSF deputy director. That helped drive the requirement for the F-35 STOVL to replace the A-10.

“When you start talking about expeditionary ops, especially forward deployed people, I don’t see any alternative to the STOVL version,” said Enewold. Nothing else in development will “get up close to the battlefield” like a short takeoff fighter.

Plans call for equipping the Marine Corps, RAF, and Royal Navy with essentially the same type of STOVL F-35, but the Air Force has unique needs. For example, the service does not need to take off within 550 feet, from the deck of a warship, as is the case with the Marine Corps. For the Air Force, a short takeoff distance is 3,000 feet. The difference provides the flexibility to add additional fuel or weapons for combat.

And Air Force discussions with the Army have produced some specific F-35 preferences. Col. Dave Watt, director of ACC’s JSF management office, has noted there is great interest in smaller weapons and longer loiter time.

With STOVL, the Air Force will be able to offer those capabilities even from short runways. The Marine Corps already emphasized close air support (CAS) capabilities while designing the aircraft, he said, and that pays benefits for the Air Force F-35B.

The A-10 has a “very specific mission,” Watt noted, and the F-16 is typically highly “missionized” to perform a specific job such as ground attack or suppression of enemy air defenses. The F-35, whether CTOL or STOVL, “will be able to do a lot more” than either of those aircraft, he said.

Gas and Gun Issues

USAF was originally interested in equipping its F-35s with a boom-style refueling receptacle, the kind of system used by all other Air Force fighters. However, Navy and Marine Corps fighters use a probe-and-drogue (basket-style) refueling system, and the F-35B is designed in this configuration.

Meanwhile, ACC officials have sought an internal gun for the aircraft, instead of the removable, less-stealthy, missionized gun specified by the Marine Corps.

“In a highly complex, dense urban environment” such as that in Iraq, the Air Force finds itself using fighter guns quite a bit, Davis said. Strafing is valuable because it is precise and causes limited collateral damage. An internal weapon maintains the airframe’s stealthy characteristics and reduces drag.

Davis said the program office informed the Air Force that STOVL F-35s could be modified to add either the boom receptacle or an internal gun, but there is not room in the airframe for both. The Air Force has chosen to go with the gun of its choice.

The cornerstone of the JSF program is low cost. Program officials acknowledge that the F-35 program faces “unprecedented affordability challenges,” and the bar has been set high. At present, the Pentagon estimates the unit cost of the vanilla Air Force variant to be $45 million, with the Navy and STOVL variants to be $60 million (as calculated in 2002 dollars).

As befits the F-35’s joint and cost-conscious nature, plans call for consolidated training. Specifics have yet to be worked out, but it is possible that all pilot and maintenance training could occur at a single location.

“We’re waiting to see what the BRAC [base realignment and closure] commission has to say,” Enewold said. Most participants “want to have some joint and combined training,” and the BRAC commission has been tasked with recommending the initial training location. Enewold added, “Then we can make a better assessment of the most cost-effective way to get the training system put in the field.”

With the weight problem evidently resolved, software development is now deemed the biggest risk area as the program office works its way toward next year’s first flight and critical design review. The F-35 will use lots of commercial-off-the-shelf software packages, Enewold said. Getting the software assembled, integrated, tested, and certified “just takes time,” he said.

The first flying fighter, dubbed A-1, is being assembled with what Enewold called “representative tooling,” but it does not have “a representative airframe.” A-1 is based on an older design and does not incorporate the weight-saving engineering changes. A-1 will fly with a production-representative engine. First flight is scheduled for late 2006.

The STOVL Diet

The Joint Strike Fighter program office and prime contractor Lockheed Martin had to slash roughly 3,000 pounds from the short takeoff and vertical landing (STOVL) F-35 last year to meet performance requirements. The changes also benefited the conventional and carrier F-35 variants, as they, too, had gotten fat.

Some of the major changes included propulsion system improvements for more thrust, a new assembly joint that weighs 160 pounds less, and a series of electrical system changes netting 222 pounds of weight savings.

Perhaps most significantly, the weapons bay was redesigned. The F-35B STOVL weapons bay has a “long and sordid story,” said Rear Adm. Steven L. Enewold, program director. The operational requirements document dictates that the carrier and conventional takeoff and landing variants have internal bays large enough for two 2,000-pound weapons; STOVL would only have to carry a pair of 1,000 pounders.

“About a year into the program, we said it would really improve our commonality and reduce our flight testing … if we could get that same weapon bay into STOVL,” said Enewold. So it was made to fit. But “when we got into the weight discussion,” officials determined the larger weapons bay had to go, so the 1,000-pound bay is back.

Opening up that internal space “allowed us to do a great many things,” Enewold said, and was “the linchpin of getting the STOVL design weight down.” The aircraft can still carry 2,000-pound weapons on wing hardpoints, and there is even an external 5,000-pound station. In an era of increasing concern about collateral damage, smaller weapons are in vogue, and this was deemed an acceptable trade. “It made STOVL viable around the ship,” Enewold said.

There are still about 300 pounds of additional weight-saving “ideas” the program office is looking into. They may not be worth implementing.

“We’re struggling a little bit,” Enewold said, because if it costs the government $50 million to cut 300 pounds, “I’m just not sure if that’s a great trade or not. The operational guys would say, ‘Great trade.’ The money people may not.”

Brig Gen. (sel.) Charles R. Davis, JSF deputy director, added that the remaining possible weight savings make for tough decisions. “Lots of items weigh five, seven, [or] 12 pounds,” he said—all the big cuts have been made.

Under the Skin

One would notice few external differences between A-1 and the current-design aircraft, Enewold noted, because “almost all the changes are inside the skin.”

Enewold said that Lockheed Martin’s Fort Worth, Tex., assembly plant may benefit from help when full-rate production begins. “When we start getting into production rates of 20 a month or so, it’s not clear to us that that kind of rate is most efficiently done at a single site,” Enewold said. The program may need two assembly sites for efficiency or surge capacity to meet foreign purchase requirements.

It is not a given that future expansion will stay in the United States: Major F-35 subsections are already being produced in Britain by BAE Systems. Northrop Grumman executive Steve Briggs told the London Sunday Times last year that, “at the peak, we’re talking about making one new JSF every day. That’s a monster to feed.” Briggs added that he doubted there are “enough high-tech milling machines in the entire US to keep pace with making the components for this production line.”

To effectively meet immediate combat requirements with minimum risk, the F-35 will be fielded through a spiral, “block” approach. The first operational aircraft, Block 1, will have modest capabilities. It will be followed in rapid succession by two more-powerful blocks.

For the initial warfighting capability, “you need to have a radar, you need to have missile warning,” an electronic warfare system, and be able to drop bombs and shoot missiles, said Enewold. Block 1 will offer stealth, air-to-air missiles, a data link, and Joint Direct Attack Munitions, he said, describing it as “pretty rudimentary warfighting.”

Block 2 will add “some close air support,” counterair, and interdiction missions, as well as an expanded weapons portfolio. The program office is trying to define exactly which Block 2 weapons “have the biggest bang for the warfighter,” Enewold said. The specifics should be locked in this October, with Block 2 operational testing complete in 2012.

Block 3 will be the full-up F-35 with solid capabilities across the entire mission spectrum, including offensive and defensive air superiority missions, suppression and destruction of enemy air defenses, and CAS. This is “the whole gamut of strike warfare,” Enewold said. Plans call for Block 3 capabilities to be frozen in 2006 with testing completed in 2013.

The program also continues to refine the mission profiles. Weight is not a key performance parameter, but range is (measured as combat radius). The STOVL is required to have a combat radius of 518 miles, the CTOL variant 678 miles, and the carrier version 690 miles. All three variants are expected to meet these standards, but the program office would like to eliminate any uncertainty.