Revised F-35 plan calls for 6 more years of testing


Details of the revamped F-35 Joint Strike Fighter program are emerging and showing that, despite more than nine years of work, almost six years of challenging development and testing still lie ahead for the Lockheed Martin-led project.

Both flight testing and software development have been re-planned using industry-standard productivity rates rather than the aggressive—and unachievable—assumptions on which the original program was built. This means many more sorties to re-fly flight-sciences test points and for regression testing of mission-system software changes.

The re-plan adds 2,000 flights to the program—for a total of 7,800, just 600 of which have been completed—and extends development testing to October 2016. In addition to more re-fly and regression flights, the new plan adds sorties for test-pilot training and builds in a 500-flight margin for unexpected flight-sciences and mission-system issues.

Of the 8 million lines of code on the aircraft, “we have 4 million to do, but we still have four years of development,” says Eric Branyan, deputy general manager of the F-35 program.

In F-35 parlance, Block 0.5 provides basic “aviate and navigate” capabilities, Block 1 introduces onboard sensor fusion, Block 2 integrates weapons and data links, and Block 3 provides the full capability planned for development.

Block 1 hardware began flight tests on mission-system development aircraft in April 2010, and is now the baseline through low-rate initial production (LRIP) Lot 4. While LRIP 1 and 2 aircraft will still be delivered with Block 0.5 functionality to begin training, this is now part of Block 1A running on the new hardware.

In addition to increasing the re¬sources for flight tests, the re-plan essentially decouples flight-sciences work on the three variants, he says. This is intended to overcome the impact of delays in testing the short-takeoff-and-vertical-landing (Stovl) F-35B on the smoother-running conventional-takeoff-and-landing F-35A and F-35C carrier variant.

The Joint Program Office (JPO), meanwhile, says each of the known problems with the Stovl F-35B are “readily solvable through engineering adjustments.” Among the issues being worked on are lift-fan clutch heating, thermal expansion of the lift-fan driveshaft and roll-post heating. Additionally, “selective redesign” of the lift-system doors is needed to “increase durability,” the JPO says.

The Pentagon will seek an additional $4.6 billion in its fiscal 2012 budget for the replanned program. This includes funds “to address known discrete improvements to include propulsion lift system, durability and structuring testing shortfalls, training systems, pilot-vehicle interface upgrades and others.”

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