Comments on F-35 Testing
By: Winslow Wheeler | January 28, 2014
The 19 page report, DoD Programs; F-35 Joint Strike Fighter (JSF) is dense, bureaucratic reading, but it also is highly informative and important. It reveals yet another chapter in the ongoing saga of problems in the F-35 program. Most problems remain unresolved; some are getting worse, and some reveal how little the F-35's advocates can be trusted.
For an excellent (non-bureaucratic) summary of the DOT&E report, see what Eric Palmer, an aviation expert and blogger from Australia, wrote. This material is found here. For another, somewhat more technical but also very insightful description, see what long time aviation journalist Bill Sweetman wrote at his Ares Defense Technology Blog here.
To supplement what they wrote, I found the following to be the salient points. They appear below in rough ascending order of importance - at least to me.
- Test Points: Although Lockheed Martin and others keep on telling us that the F-35 flight test program is ahead of schedule on flight test hours and test flights, it is behind schedule on why those test flight are flown: planned test points. The discussion and table on page 34 of the attached shows the flight test program "accomplished" only 5,464 of 7,180 of the planned "baseline" (originally planned for 2013) test points. That's 24 percent fewer than were originally planned; the "mission systems" (software) test points are 46 percent behind. Other test points were also "accomplished," but they were added to the program once it was determined all planned test points could not be flown. Note that "accomplished" does not mean the F-35 passed-just that the test was flown.
- Bubbling/Peeling Stealth Coatings: The previous problem of stealth coatings degrading on the tail sections of all variants at high speed after extended afterburner use was not fixed by new coatings. The test program will collect new data; in the meantime, "non-instrumented" aircraft will have restrictions on their flight envelope and use of afterburners.
- Buffet and trans-sonic roll-off (TRO): All F-35 variants are experiencing turbulence and uncommanded "wing drop:" put simply, the aircraft is not flying as designed, and the aircraft sometimes does things on its own, uncommanded. We were told in congressional testimony this was fixed by changes in the flight computer's control laws. It seems that is not so; the bad aerodynamic behavior was reduced, but it was not eliminated, and the computerized flight control changes have been exhausted as a solution. The only possible solution is a hardware change to the wing (very costly) or computer-directed limitations restricting various pilot maneuvers (also very costly-in pilots' lives in combat).
- Helmet-Mounted Display System (HMDS): The overpriced, foolishly complicated helmet system continues to have problems with "jitter," "swimming" images, unacceptable night vision, "double vision" and alignment with the real world. Other fixes, including latency and light leakage have either not been tested realistically or impose a higher pilot work load. Nonetheless, last year there were reports, including from GAO, that all these problems were on the mend.
- Software: As discussed by Eric Palmer below and Reuters last week, F-35 software development is falling well behind schedule, and although the DOT&E report does not make it explicit in plain language, the delays are beginning to seriously threaten the Marine Corps and Air Force plans to declare "initial operational capability" (IOC) in 2015 and 2016, respectively. The quote on page 40 says "Initial results with the new increment of Block 2B software indicate deficiencies still exist in fusion, radar, electronic warfare, navigation, EOTS, Distributed Aperture System (DAS), Helmet-Mounted Display System (HMDS) and datalink." That says a lot.
Maintainability: Reliability is poor and ranges from 30 to 39 percent behind the current objective. The table on page 47 shows that the "availability" of the existing fleet is getting worse and has never reached, is receding from, its quite modest threshold of 50 percent at this stage in the program. The amount of time needed to repair failures "has increased over the past year." (Page 48.) The Autonomic Logistics Information System (ALIS) "is immature and behind schedule," and fixes applied to date are not working (Page 49.)
- Survivability: There are several problems that make it clear the F-35 is highly vulnerable, the following passage is one example of a real problem: "The fuel ingestion tests did not simulate engagements by ground-based or aircraft gun systems that are possible during low-altitude close-air support missions and within-visual-range air-to-air combat. A Concept Demonstrator Aircraft engine test in 2005 showed the engine could not tolerate fuel ingestion events representative of such conditions (i.e., low-altitude, high speed, high-engine thrust, and higher leak rates). The program made no design changes in response to those earlier test results and this vulnerability remains in the final production engine design. A ballistic liner in the fuel tank could mitigate this vulnerability, but the program removed this feature during its weight-reduction efforts, saving 48 pounds."
There are other details, none of them happy, such as the newly revealed cracks in the airframe.
The report ends with a recommendation that should attract much positive attention, although it will almost certainly be roundly ignored, especially by the F-35 program office, Lockheed Martin and-therefore-Secretary of Defense Hagel.
The report recommends on page 52 that the F-35 with its block 2B software should be tested in direct comparison with legacy aircraft. In other words, it should be empirically established if the F-35 is a step forward, or a step backward.
For example, testing in direct comparison to the A-10 for which aircraft should perform the close air support role would be a particularly interesting exercise. Is there a single performance characteristic that is central to the close air support mission where the F-35 can outperform the A-10? Is there even a close air support performance criterion where it can match the A-10?
Is there someone in authority, either in DOD or Congress, who would like to find out and insist on such comparative testing?