April 17, 2024

Big Week for JSF

By Jay Friess

Yesterday, two Lockheed Martin test pilots went on an Internet broadcast to tout the “synergistic quantum leap effect” that the Joint Strike Fighter will have on future military air operations.

The event happened just after the release this week of the Pentagon’s Developmental Test and Evaluation report, which found significant problems and shortcomings within the program.

The event was also timed to precede Secretary of Defense Leon Panetta’s scheduled visit to Naval Air Station Patuxent River today to review the progress of the JSF program and possibly take the F-35B variant off the probation status his predecessor, Robert Gates, placed it under a year ago.

The Lockheed event began with Alan Norman, F-35 Chief Test Pilot for Lockheed, giving a brief presentation on the state of the program from his office at Edwards Air Force Base in California. Norman noted that the program completed 7,000 test points in 2011, taking the Air Force version of the jet to Mach 1.6 and into 9 G turns.

“We’re setting the stage for the continuation of a very successful test program,” Norman told the Internet audience of mostly reporters. He stated that weapons separation and air start testing will begin soon. “2012 will be a busy and exciting time.”

The Pentagon’s report concedes that the program did accelerate its test schedule in 2011, but criticized its plan to concurrently test and build the aircraft in order to field the jet faster. Simultaneous production and testing has caused the program’s costs to balloon. The Air Force and Marines have had to begin training with immature aircraft and spend billions on retrofitting older aircraft with structural improvements.

Despite an accelerated test flight schedule in 2011, the DOT&E report notes that the Marines short takeoff and vertical landing variant of the JSF, the F-35B, is still 9 percent behind its development schedule. However, the Navy’s F-35C aircraft carrier-based variant is 32 percent ahead.

The report specifically called out the aircraft’s new helmet, which integrates sensor input and the jet’s displays into a single field of vision for the pilot. The report noted the plane’s “poor performance in the human systems integration (e.g.
helmet-mounted display, night vision capability)” as a factor that needs to be addressed to pass its operational assessment.

“We get what some pilots call jitter,” Norman admitted at the Lockheed press event, referring to test pilot reports of the helmet lagging and getting out of sync. But he said the problem is overblown and is being addressed. He said press reports of the helmet under-performing is “not the full picture of what’s going on with the helmet.”

Bill Gigliotti, a Lockheed test pilot stationed at Pax River, stated that engineers are adding micro intertial measurement units to the helmet to help its reaction time and stability. “We love the helmet, and we’d rather have the helmet,” Gigliotti claimed, stating that the helmet is intuitive to use and displays information in a better way than traditional displays.

While the Navy’s F-35C is ahead on the testing charts, it faces a significant hurdle. It has so far failed to complete a trap landing, in which the hook on the back of the aircraft catches arresting wires, similar to those found on an aircraft carrier.

“Flight test aircraft could not engage the arrestment cable during tests at the Lakehurst, New Jersey, test facility,” the report states. “The tail-hook point is undergoing a redesign and the hold-down damper mechanism requires modifications to enable successful arrestments on the carrier. Resolution of these deficiencies is needed for testing to support F-35C ship trials in late 2013.”

However, Gigliotti claims the aircraft will be ready in time for shipboard operational testing. “We’ll meet that, just like we met that with the STOVL version last year,” Gigliotti said.

The program has yet to do significant integrated testing of the F-35’s most complex mission systems. “Overall, the program has demonstrated very little mission systems capability thus far in flight test on F-35 aircraft,” the report states. “In fact, the program has not delivered some of the intended initial training capability, such as effective and consistent radar performance.”

And the report found that “live fire tests and analyses showed the fuel tank inerting system is incapable of providing protection from threat-induced fuel tank explosions during some critical of combat missions when the aircraft is most likely to be hit. The program is redesigning the system.”

The program successfully completed shipboard testing of the Marines’ short takeoff and vertical landing variant, the F-35B, in Oct. 2011, but significant problems are surfacing in the aircraft. The reports notes that the F-35B test team halted durability testing late last year when they found a “wing carry-through bulkhead cracked before 2,000 hours of airframe life. The required airframe lifetime is 8,000 hours. Repair of the bulkhead on the test article was completed in November 2011, and F-35B durability testing is scheduled to restart in January 2012.”

“Following the bulkhead crack in the F-35B test article, analysis verified the existence of numerous other lifeňúlimited parts on all three variants,” the report states. “The program began developing plans to correct these deficiencies in existing aircraft by repair/modifications, and designing changes to the production process. The most significant of these in terms of complexity, aircraft downtime, and difficulty of the modification required for existing aircraft is the forward wing root rib on the F-35A and F-35B aircraft.”

The shipboard testing exposed another problem with the F-35B – weight.

“The F-35B aircraft weight management challenge is complicated by balancing available lift, thrust required, and vertical descent rates in the vertical landing mode,” the report notes. “Current and projected F-35B aircraft weight growth threatens the ability to meet this vertical lift bring-back requirement. The November 2011 weight data show only 230 pounds of margin between the current weight and the intended not-to-exceed weight of 32,577 pounds, which is the program’s technical performance measurement threshold for empty aircraft weight currently programmed for January 2015.”

The F-35B is scheduled to head out for shipboard testing again in Aug. 2013.

The F-35B team has not developed the jet’s STOVL flight mode to sufficient maturity, so the report states that “production aircraft will be restricted from STOVL-mode flight operations until Service airworthiness authorities grant a flight clearance.” If testing is not complete soon, then four F-35Bs scheduled to ship to Yuma, Ariz. for training later this year will be restricted to flying in conventional mode only.

When asked which variant they liked the best, Norman, who has flown the F-35A and F-35B, said he liked them equally. Gigliotti has flown all three variants and said, “They all fly the same; they all fly equally.” However, he admitted, “My favorite airplane is the one I’m sitting in.”

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