A major operational test series planned for the Lockheed Martin F-35 Joint Strike Fighter has been abandoned in an attempt to protect the schedule for delivering a fully operational aircraft, according to the just-released fiscal 2014 report on the program from the Pentagon’s Director of Operational Test & Evaluation (DOT&E).

Also, the Block 2B version of the fighter’s software, at the time of a review at mid-year, contained 151 mission-critical deficiencies, some of which may not be corrected until the final Block 3F is completed.

The Operational Utility Evaluation (OUE) of the Block 2B configuration – the Block 2B is the basis for the Marine Corps’ plan to declare initial operational capability with the F-35B later this year – was removed from the schedule in April 2014 on DOT&E’s recommendation. The critical schedule item was the time needed to bring enough aircraft to a representative Block 2B configuration to support the OUE, which would have delayed the start of the evaluation into late 2016. This in turn threatened to delay the development of Block 3F software.

Rather than carrying out a full OUE, "limited assessments" of Block 2B capability will be carried out using F-35A operational test aircraft at Edwards AFB, California.

Developmental testing of the Block 2B software is expected to be complete next month, earlier than the DOT&E predicted in last year’s report (May to November 2015). Most of the improvement came from a decision by the program office to consolidate test points from earlier blocks into 2B testing, eliminating a net 840 test points, equivalent to four months of testing.

The critical risk to Marine IOC identified in the new report is the availability of "mission data load" software, which works in conjunction with software permanently loaded in the aircraft system and contains information to operate sensors – for example, the data needed to identify hostile radars. The operational requirement is for these to be generated in a government facility, the U.S. Reprogramming Lab (USRL), but some equipment for the USRL was held by Lockheed Martin three years past its due delivery date. On baseline plans, the first two mission data loads will not be available until November, but the report refers to a plan to "truncate" development and carry out limited flight tests, creating "significant operational risk to fielded units."

DOT&E also notes that an apparent improvement in a major reliability metric — "mean flight hours between failure – design controllable" — up to late summer 2014 may be due to changes in reporting. More failures were reported as "induced," or due to maintenance actions, and fewer to "inherent" design problems. Also, once a redesigned version of a failure-prone part is introduced into the fleet but before 100% of the fleet has been retrofitted, the program stops counting failures of the previous version, improving the system’s on-paper reliability even though failures are occurring.

One of the F-35’s distinctive features, the Distributed Aperture System, is still problematical, the report says, continuing "to exhibit high false-alarm rates and false target tracks, and poor stability performance, even in later versions of software."

Lockheed Martin and the JSF Program Office had not responded to the report by midday on Jan. 20.