The Pentagon's official F-35 bug list is terrifying

The first contracts to design what became the F-35 were handed out 20 years ago. Lockheed's X-35 won the contract in October, 2001. Fifteen years later, the aircraft is in terrible condition -- a fact driven home by the DoD's own official report on the state of the F-35 and the bugs that continue to plague it.

The report was released two days ago(Opens in a new window), but a number of links to the PDF have died; you can access the HTML text via Google cache(Opens in a new window) if the above isn't working. It discusses all variants of the F-35, but focuses on the F-35B, the short-takeoff-and-vertical-landing version of the aircraft developed for the US Marines, and adopted by the Royal Navy as well as the RAF.

The state of the F-35

Before we dive into the report's findings, we need to cover some of its terminology. The Air Force uses block numbers to denote differences in an aircraft's capability. Sometimes these block numbers are specific to an entire aircraft (e.g., the F16A/B Block 20). In the F-35's case, there are also block numbers for many of its subsystems.

If used in combat, the Block 2B F-35 will need support from command and control elements to avoid threats, assist in target acquisition, and control weapons employment for the limited weapons carriage available (i.e., two bombs, two air-to-air missiles). Block 2B deficiencies in fusion, electronic warfare, and weapons employment result in ambiguous threat displays, limited ability to respond to threats, and a requirement for off-board sources to provide accurate coordinates for precision attack. Since Block 2B F-35 aircraft are limited to two air-to-air missiles, they will require other support if operations are contested by enemy fighter aircraft.

Block 3i began with re-hosting immature Block 2B software and capabilities into avionics components with new processors. Though the program originally intended that Block 3i would not introduce new capabilities and not inherit technical problems from earlier blocks, this is what occurred. The Air Force insisted on fixes for five of the most severe deficiencies inherited from Block 2B as a prerequisite to use the final Block 3i capability in the Air Force IOC aircraft... However, Block 3i struggled during developmental testing (DT), due to the inherited deficiencies and new avionics stability problems.

Block 3F also began development in March 2015, 11 months behind schedule. It's far behind where it's supposed to be; the DoD states that Block 3F developers spent most of 2015 squashing bugs in Block 3i.

For want of a nail

The F-35's buggy flight software is scarcely the only problem. The F-35 loads specific profiles for every mission it flies. These profiles are designed to "to drive sensor search parameters and to identify and correlate sensor detections, such as threat and friendly radar signals."

Currently, the US Reprogramming Lab is plagued by "significant deficiencies that preclude efficient development and adequate testing of effective mission data loads for Block 3F." Despite being given a $45 million budget in fiscal year 2013, the USRL has not engaged in the necessary upgrades. The estimated time to finish the upgrades is two years. Without them, the DoD estimates the F-35 faces "significant limitations" to its combat capability against existing threats.

Eleven of the 12 events required intervention by the developmental test control team to overcome system deficiencies and ensure a successful event (i.e., acquire and identify the target and engage it with a weapon). The program altered the event scenario for three of these events, as well as the twelfth event, specifically to work around F-35 system deficiencies (e.g., changing target spacing or restricting target maneuvers and countermeasures).

The laundry list of problems continues. There's no Verification Simulation in place for the F-35, despite eight years of work and $250 million in funding. The average availability of the F-35 for operations was 51% in 2015, well below the 60% availability goal. (This metric has, at least, improved in recent years.) The F-35 spent 21% more time down for maintenance and waited 51% longer for parts than anticipated. Between 10-20% of the fleet was grounded at any given time, due to the need to rework the aircraft to install upgrades or for repairs.

Ejecting might kill you

Ejection tests on the F-35 are troubling, to say the least. The third-generation helmet display system for the F-35 is heavier than its predecessors, which may be causing issues for the aircraft. Pilots weighing less than 136 lbs are prohibited from flying the F-35, because the ejection seat tests show stresses that'll snap the neck of regular human beings.

Pilots between 136 and 165 lbs are cleared to fly the F-35, despite a formal "serious" risk rating. Again, here's the DoD: "The level of risk was labeled 'serious' by the Program Office based on the probability of death being 23 percent, and the probability of neck extension (which will result in some level of injury) being 100 percent. Currently, the Program Office and the Services have decided to accept this level of risk to pilots in this weight range, although the basis for the decision to accept these risks is unknown."

The failure of concurrency

The F-35's problems are at least partially the result of allowing Lockheed Martin to pursue concurrent flight design and active deployment. The idea behind concurrency was that Lockheed Martin could begin building an aircraft while still fine-tuning various aspects of its design. In theory, applied to much simpler vehicles, it might have worked, especially if the F-35 had been a modest evolution of an existing aircraft.

Applied to the F-35, concurrency has been a disaster. Right now, every single F-35 already built will need to be extensively overhauled to meet its minimum performance targets. It's one thing to overhaul a ship or aircraft to improve its baseline capabilities, and something else entirely when the aircraft as delivered can't execute its mission.

The report argues strongly against the use of a so-called "block buy" strategy in which up to 270 aircraft would be purchased in bulk to achieve theoretical savings. If F-35 production continues at its current rate, more than 500 aircraft will have been built by the time the design is finalized -- and all of them will need to be refitted to one degree or another to "provide full Block 3F combat capability."

The F-35 isn't just the most expensive fighter plane ever built, with total program cost estimates over the lifetime of the aircraft now between $320 - $400 billion, depending on how you count. It's also expected to spend the longest in development.

Just for fun, I pulled data on a number of other high-profile US aircraft over the last forty years. The F-16 and F/A-18 took six and eight years to go from first flight to combat-certified. The B-2 Spirit stealth bomber first flew in 1989 and was fully certified only in 2003, some 14 years later. The F/A-18E (Super Hornet) had a quick bring-up time of just five years, while the F-22 Raptor took a decade between first flight and full certification. Clearly the trend has been towards longer development times; the F/A-18E is an outlier in that regard.

With that said, the F-35 is in a class of its own. First flight took place in 2006. According to the DoD, full WDA testing on the Block 3F software won't be complete until 2021. By that point, the Block 4 software should be in the field. It's not clear from this report which milestones must be passed to certify the aircraft as fully operational. But if the WDA tests are part of that process, it'll be another five years before the F-35 is "done" -- a full 50% longer than any aircraft has taken before.