750 F-35s Now Delivered, Navy To Put Some Of Its Oldest Test Models Into Storage

The F-35 program has hit a major production milestone as primary test efforts are finally spinning down.

byJoseph Trevithick|
F-35 photo


The U.S. Navy is looking for a contractor to help put three early F-35 Joint Strike Fighters, two B models and C variant, which are no longer needed for flight testing purposes, into storage. This decision reflects the progress that has been finally made in moving the F-35 program out of its long-troubled testing phases. There is hope that this year the Pentagon may finally approve formal full-rate production of the jets, more than 750 of which have been delivered to customers around the world to date.

The Naval Air Systems Command's (NAVAIR) Naval Air Warfare Center Aircraft Division (NAWCAD), which is headquartered at Naval Air Station Patuxent River in Maryland, first revealed it was looking to put the F-35s in question into long-term storage in a contracting notice it posted online on Dec. 30, 2021. The three jets are presently at Patuxent River.

An F-35B test jet., Lockheed Martin

At least 19 F-35s of various models, including a number of non-flying ground test articles, were built specifically for testing purposes as part of the SDD phase of the program. Lockheed Martin won its first Systems Development and Design (SDD) contract in 2001 and this phase is still technically ongoing. In 2018, the program did conclude developmental flight testing, transitioning to operational testing and evaluation.

"With the conclusion of the Systems Development and Design (SDD) portion of the F-35 flight test program, three of NAS Patuxent River F-35 Integrated Test Force (ITF) flight science aircraft (x1 F-35C and x2 F-35B) are no longer required to gather flight test data," the notice explains. "Therefore, it has been determined at the F-35 Joint Program Office (JPO) that these aircraft will be preserved via a preservation/protection system (i.e. shrink wrap) and transported elsewhere for other uses at a later date."

Some of the key details about the Navy's plans to put three F-35 test aircraft in storage from a recently released contracting annoucement., USN

Though referred to colloquially as 'shrink wrapping,' the preservation process actually involves the application of a more complex set of coverings in order "to keep the jets in its [sic] original state to keep the jets from damage due to the installation/removal of the preservation system, weather, moisture, and corrosion." This is particularly important for storing stealthy aircraft like the F-35, the radar-absorbent skins of which are made of materials that are notoriously sensitive to environmental conditions.

'Shrink-wrapped' F-16 fighter jets at the Air Force's main boneyard at Davis-Monthan Air Force Base in Arizona., USAF

Whichever contractor NAWCAD ultimately hires to do this work, which it hopes will be done between the beginning and the end of March of this year, will need to configure the jets in such a way that they can be craned onto trucks for movement to the designated storage site. The contracting notice does not state where that site might be, but does say that it be "elsewhere" in relation to Patuxent River.

A truck carries an F-35A ground test article to Wichita State University’s National Institute for Aviation Research in June 2018., KDOT

NAWCAD's contracting notice also defines "long term storage" by saying that "the jets will be stored outside in the sun and weather for up to five (5) years." It's not clear whether or not that means the expectation at present is that the jets will only be in storage for five years or less and there are no indications about what the Navy's plans might be for the aircraft after that point. The contracting notice does mention the possibility of "other uses at a later date" for these planes. 

How useful F-35 flight science aircraft might be for future testing of any kind is unclear. The Joint Strike Fighter was developed using a process known as "concurrency," meaning that aircraft were built with the understanding that there would be a need to integrate various fixes and modifications onto early jets as the SDD phase progressed. This was initially presented as a cost-saving concept, wherein production could be ramped up early on in the development process, but has led to cost increases and schedule delays that are likely to persist for at least some years to come still. 

A Joint Strike Fighter being built., Lockheed Martin

In addition, this means that early jets are significantly different on many levels, even in their basic structure, from aircraft in later production lots. For instance, the differences are so significant that the Air Force is considering not upgrading entire batches of early production F-35As to the current standard configuration due to the costs involved. The F-35 JPO also canceled a third round of structural testing relating to the F-35B after determining the relevant "test article to no longer be representative of the wing-carry-through structure in production aircraft," according to the most recent annual report on the Joint Strike Fighter from the Pentagon's Office of the Director of Operational Test and Evaluation. Beyond all this, test aircraft typically have specific systems and associated wiring, among other things, giving them distinct weights and performance specifications compared to production examples in any configuration.

An F-35 ground test article undergoes structural testing., Lockheed Martin

It is possible that the Navy or the F-35 JPO, or some other branch of the U.S. military or other government agency, such as NASA, might have some interest in using these early F-35s for other kinds of testing in the future, including destructive testing on the ground, or for use as training aids. The War Zone has reached out to NAWCAD for more detailed information about its current plans for the jets.

No matter what, the Navy's lack of immediate need for these three flight sciences F-35s does highlight the program's progress toward finally bringing the SDD phase to a close after more than two decades. The F-35 JPO still needs examples of the F-35A, B, and C to at least pass various tests in an advanced simulated training environment, scheduled to take place this year, before the Pentagon will give manufacturer Lockheed Martin formal approval to begin full-rate production of these aircraft. The full-rate production decision should coincide with the end of operational testing and evaluation, which will mark the official end of the SDD phase, according to Lockheed Martin. In 2009, before the Pentagon decided to "re-baseline" the entire program due to cost overruns and delays, the expectation was that this milestone would come in 2013.

It is worth noting that the total number of F-35s that Lockheed Martin is building every year as part of what is technically low-rate production could easily be considered full-rate production for many other types of military aircraft. The company delivered 142 Joint Strike Fighters of all variants in 2021, according to a press release it put out today. This is eight more than the 134 in 2019, which represented the previous yearly record, and 21 more than in 2020. Steve Trimble, Aviation Week's Defense Editor and friend of The War Zone noted on Twitter more than half of all F-35s ever built, more than 750 in total, have been delivered to their customers just in the last three years.

Still, while the F-35 program has seen significant progress toward finally wrapping up its SDD phase, concerns are now growing about how much it will cost to operate and sustain these jets in the decades to come. A fourth major block of upgrades is already in development, but is still years away from being integrated into any of these jets and it's not clear how much this will add to the program's total price tag. As of 2019, the U.S. government estimated that it could cost the U.S. Air Force, Marine Corps, and Navy around $1.196 trillion to maintain their full expected fleets of F-35A, B, and C aircraft through 2070. It's important to note that this is based in part on the Air Force's stated plans to buy a total of 1,763 F-35As, a procurement plan the service is now in the process of deciding whether it wants to scale back.

At the same time, the global F-35 family continues to grow. In 2021, Switzerland and Finland became the latest countries to announce plans to purchase these jets. Last year, Canada also announced that the F-35A, along with Saab's Gripen E, were the finalists in its current fighter competition. Nine countries, including the United States, are already flying F-35 variants. The total number of variants and subvariants looks set to grow as the number of operators expands, as well, with Israel notably flying the distinct F-35I Adir version and another type is now under development for an unspecified foreign customer.

As the F-35 program continues to progress, it will be interesting to see what the future will hold for older F-35s, including the three test jets the Navy now wants to put into long-term storage. 

Contact the author: joe@thedrive.com