What is in a date? For the $400 billion, multinational F-35 fighter program—different things to different customers. But, after three years of discussion about when their first units will be ready for combat, the U.S. Marine Corps, Air Force and Navy are confident enough in the development program to outline firm initial operational capability (IOC) plans.

Though much additional work remains for the single-engine, stealthy fighter's software and helmet system, the services each take different approaches to just what constitutes “ready” and when that will happen.

The first U.S. IOC date is just 18 months away for the Marine Corps, followed a year later by the Air Force and the Navy, in February 2019. After years of delays and billions of dollars in cost overruns—pushing earlier attempts at IOC planning back—the top brass had shied away from publicly outlining firm plans out of fear technical problems in the fighter's $61 billion development program would call for yet more schedule revisions. Congress, however, stepped in and demanded a resolution on IOC planning, prompting the services' decisions outlined in a May 31 report to Capitol Hill.

Though each service's leadership is publicly expressing confidence in the way ahead, especially since the Pentagon last overhauled the project in 2010, the program's ability to meet the newly established IOC dates depends heavily on progress in flight and structural-durability testing slated to wrap up in 2017. The biggest risk, according to F-35 Program Executive Officer USAF Lt. Gen. Christopher Bogdan, is in crafting, testing and releasing incremental software packages needed to operate the sophisticated fighter.

Another unknown is the outcome of a risk-mitigation plan put in place two years ago to address mounting concerns about the F-35's revolutionary helmet-display system. If the system falls short of its requirements, key tasks such as nighttime aerial refueling and shipboard vertical landing will be severely hampered.

The Pentagon-led F-35 Joint Program Office prompted Lockheed Martin to select a second helmet contractor in 2011 as a backstop in the event the primary system, designed by Vision Systems International (VSI), failed to overcome persistent problems with night-vision acuity and jitter in its Gen 2 helmet. The parallel developments are ongoing (see page 18). But, risk still remains as officials at VSI, a joint venture of Rockwell Collins and Elbit, are planning to install a new night-time camera into the helmet and incrementally introduce equipment to address the near-field, night-vision acuity issue and other problems. The result, a so-called Gen 3 helmet, is expected to fly in the F-35 in January.

As the first of 15 expected customers, the Marine Corps is likely facing the most risk. That service is expected to meet the IOC with 10 F-35Bs designed for short takeoff and vertical landing (Stovl) in December 2015. The aircraft will be outfitted with the 2B software package and the requisite trained pilots and maintainers, along with adequate support equipment. This is a slight shift of the most recent plan to reach that milestone in summer 2015.

The Marines are more aggressive than their sister services out of eagerness to replace aging F/A-18 Hornets, followed closely by the AV-8B Harriers, which will remain in service until 2030. “The F-35 is our country's best hedge against the ever-evolving and unknown threats posted by our adversaries,” says Marine Lt. Gen. Robert Schmidle, the service's top aviation officer.

But, by going first, the Marines are compromising on the capabilities initially inherent in their F-35 fleet. The 2B software will include basic close-air-support and interdiction capabilities as well as initial air-to-air and data-linking capabilities. Weapons included will be the AIM-120C7, Joint Direct Attack Munition and GBU-12 laser-guided, 500-lb. bomb, although the load is limited to the internal weapons bay; external stores are not included in the 2B release.

Italy is planning to buy the F-35B as is the U.K., which is participating in the flight-testing program with its aircraft.

The U.S. Air Force, by far the largest F-35 presumed user, has agreed to declare IOC with a much more limited software-and-weapons capability than originally planned.

The 12 F-35As (and trained pilots and maintainers) needed by the Air Force will support an IOC in December 2016, before the long-awaited 3F software package is fully tested. The Air Force had planned to wait for the 3F package because it allows for an expanded engagement envelope and more diverse weapons. Instead, the Air Force is moving ahead with the 3I package, which includes the basic weapons and envelope of the 2B used by the Marine Corps, but with updated processing hardware. “This [plan] is capability-based” and the 3I software satisfies the service's initial needs, says an Air Force spokeswoman. “We still believe we need 3F for full mission capability.”

The 3F package adds capabilities that are key to the F-35's core mission‚ such as multiship suppression, destruction of enemy air defenses and new air-to-air and air-to-ground modes. It also will include the full complement of weapons carried internally and externally. It is slated for inclusion on the low-rate initial-production (LRIP) 9 aircraft, and is expected for delivery at the end of the development program in 2017.

In testimony to Congress this spring, Bogdan said there is “moderate” risk in prime contractor Lockheed Martin delivering the 2B package in 2015, while he acknowledged more risk in meeting the 3F schedule two years later.

“The F-35 is a vital capability that the nation needs to stay ahead of adversary technological gains, and it provides the multirole capabilities that the anti-access and area-denial environment of the future will require,” said USAF Gen. Mark Welsh, Air Force chief of staff.

Lockheed Martin had fallen a few months behind in delivering on the 2B software release needed by the Marine Corps for IOC, but the package is now being tested in the lab. And, early flight trials have begun, according to Laura Siebert, a company spokeswoman. Flight-testing of the Block 3 capability is slated to begin within the next couple of months, she adds. Meanwhile, the Block 1 capability—suitable only for very basic flying—and the incremental step-up to 2A is being used for flight-training at Eglin AFB, Fla., and the first operational squadron of F-35Bs for the Marine Corps at Yuma, Ariz.

The Air Force plans to buy 1,763 F-35As; the A-model is expected to be by far the largest international seller to JSF partners—Australia, Canada, Denmark, Italy, the Netherlands, Norway Turkey and the U.K.—as well as to Israel, Japan and, possibly, South Korea and Singapore.

The Navy, which has pursued a risk-mitigation strategy of buying Boeing F/A-18E/Fs and EA-18Gs while waiting for the F-35C, is taking a more conservative approach toward the aircraft carrier-capable F-35C. The service plans to declare IOC in February 2019, well after the 3F software's anticipated operational testing phase in late fiscal 2017. Navy leadership emphasizes in its statement about its IOC plans that it will need the F-35C to “find, fix and assess threats, and, if necessary, track, target and engage them with lethal results in all contested environments.” These capabilities will require, at the least, 3F software as well as training to a larger mission set for an IOC declaration.

By contrast, the Marine Corps and Air Force are taking an incremental approach, allowing for limited use of the aircraft for IOC with a growth path as more capability is delivered to the fleet, eventually culminating in a full-operational capability.

This strategy, however, exposes the first adopters to retrofitting the early aircraft they accept into service with modifications such as the improved software and upgraded helmet system.

Now that the services have their IOC plans on the table, they can better craft strategies for retiring older aircraft in favor of the F-35. These include the F-16C/D, A-10, AV-8B and F/A-18.

The IOC blueprint establishes a benchmark and puts pressure on Lockheed Martin to make good on its software testing plans. “I believe the aircraft design and technological capabilities of the F-35 are sound and the Joint Program Office will deliver on our commitments to meet service timelines,” Bogdan says.