The Lockheed Martin F-35 Lightning II has made some progress, but continues to fall short in many areas.

That’s according to the Pentagon’s top weapons tester, the Office of Director of Operational Test and Evaluation (DOT&E), which wrote in a report released 31 January that the stealth fighter’s performance, as well as Lockheed Martin’s fixes and upgrades for the aircraft, failed to meet agreed upon standards in 2018.

Lockheed Martin acknowledged that there are issues with the F-35.

“Items identified in the Annual DOT&E report are well understood and have been resolved in partnership with the F-35 Joint Program Office or have an agreed path forward to resolution,” the company says.

Nonetheless, the aerospace manufacturer's struggles to eliminate 15 category one deficiencies with the stealth aircraft come as the programme started Initial Operational Test and Evaluation (IOT&E) in December, a battery of tests that must be passed before DOT&E approves the aircraft for full-rate production. Approval for full-rate production would allow Lockheed Martin to get a multiyear order for the aircraft from the Defense Department, an agreement that the manufacturer hopes to have signed by around 2022 and would be a stronger guarantee of future business than its current contracts.

Lingering deficiencies come as DOT&E says that its durability testing has shown that the service life of early-production F-35B aircraft – the short take-off and vertical-landing variant for the US Marine Corps – is well under the expected service life of 8,000 flight hours, and may be as low as 2,100 flight hours. As a result, USMC F-35B aircraft are expected to start reaching their service life limit in 2026.

In response to the report, Lockheed Martin says planned modifications to early F-35Bs should help the aircraft meet the 8,000h service life requirement. Recently delivered aircraft also incorporate those design changes in the build process.


Lockheed Martin F-35B Lightning II


In addition to a predicted shortened lifespan for the short take-off and vertical-landing variant, DOT&E found there was no improvement in aircraft availability across all operational F-35 aircraft.

“Fleet-wide average availability is below program target value of 60% and well below planned 80% needed for efficient conduct of IOT&E,” says the testing office. “The trend in fleet availability has been flat over the past three years; the program’s reliability improvement initiatives are still not translating into improved availability.”

Lockheed Martin argues reliability is improving, as newer aircraft are averaging better than 60% mission capable rates, with some operational squadrons near 70%.

The testing office also restated its criticism of the Continuous Capability Development and Delivery (C2D2) strategy for the F-35, noting that despite Lockheed Martin’s use of agile software development methods the plan to deliver large amounts of upgrades in six-month increments is “high risk.”

“Other modern fighters (e.g., F/A-18, F-22) have historically taken much longer than six months – two and three years, respectively – to field new increments of capability,” says DOT&E. “A more realistic C2D2 schedule with achievable content releases that includes adequate test infrastructure (labs, aircraft and time) and modifications while aligning the other fielding requirements is necessary.”

Additionally, Lockheed Martin’s Autonomic Logistics Information System (ALIS), which is designed to automatically track the F-35’s health, recommend maintenance and order replacement parts, in many situations is not making life easier for aircraft maintainers; indeed, it's making their work more difficult.

“Users must employ numerous workarounds due to data and functionality deficiencies. Most capabilities function as intended only with a high level of manual effort by ALIS administrators and maintenance personnel,” says DOT&E. “Manual workarounds are often needed to complete tasks designed to be automated. Configuration management of ALIS software and data products remains complex and time-consuming. Users must deal with pervasive problems with data integrity and completeness on a daily basis.”

Lockheed Martin says it is investing money to address various DOT&E and user complaints.

And, the DOT&E noted “unacceptable” problems with the accuracy of the F-35A’s internal cannon after flying 19 ground strafing test missions.

“Investigations into the gun mounts of the F-35A revealed misalignments that result in muzzle alignment errors,” says DOT&E. “As a result, the true alignment of each F-35A gun is not known, so the program is considering options for re-boresighting and correcting gun alignments.”

The F-35B and F-35C aircraft have unique gun pods, which are carried externally, and are accurate, says DOT&E.

Story updated on 1 February to include comments from Lockheed Martin.