27 avril 2020 | International, Aérospatial

Five F-35 issues have been downgraded, but they remain unsolved

By: Aaron Mehta , Valerie Insinna , and David B. Larter

WASHINGTON — The F-35 Joint Program Office has put in place stopgap fixes for five key technical flaws plaguing America's top-end fighter jet, but the problems have not been completely eliminated.

Last June, Defense News reported exclusive details about 13 major technical issues, known as category 1 deficiencies, impacting the F-35. The JPO has since quietly downgraded five of those issues to the lesser category 2.

A category 1 deficiency is defined as a shortfall that could cause death, severe injury or illness; could cause loss or damage to the aircraft or its equipment; critically restricts the operator's ability to be ready for combat; prevents the jet from performing well enough to accomplish primary or secondary missions; results in a work stoppage at the production line; or blocks mission-critical test points.

In comparison, a category 2 deficiency is of lesser concern — something that requires monitoring, but not something that should impact operations.

But downgrading the category doesn't mean the problems are solved, said Dan Grazier, who tracks military issues for the Project on Government Oversight.

CAT 2 programs are still "definitely cause for concern. They are going to have an impact on how the aircraft performs,” Grazier said. "It really depends on what the issue is, but every design flaw has a potential issue on the mission. ... You want to not have flaws, you want these things can be fixed so pilots can get out and do what they need to do.”

Aside from a few basic statements on which projects were downgraded to CAT 2, a JPO spokesperson said the office “cannot disclose any information about how these deficiencies were resolved or downgraded due to their security classification.”

The ALIS sovereign data transfer solution does not meet information assurance requirements.

The Autonomic Logistics Information System, or ALIS, provides the backbone of the F-35, used by the aircraft's operators in virtually all stages of flying and sustaining the Joint Strike Fighter. The system is used to plan and debrief missions, order spare parts, walk maintainers through repairs, and view technical data and work orders. (A potential replacement, named ODIN, is in the works.)

But some international partners on the F-35 program have expressed concerns that data flowing through ALIS to the United States government — and to Lockheed Martin — could give both the U.S. military and the American defense contractor a window into that country's flight operations, including when and where its F-35s are flying.

Those concerns were so high that two countries threatened to leave the program entirely if a fix was not quickly applied, according to the original documents viewed by Defense News.

That fix is now in, according to the JPO, which said that on April 29, 2019, an update to ALIS included an initial version of a new Sovereign Data Management tool.

“The SDM tool permits F-35 operators more control over the types of Prognostics and Health Management (PHM) data that are transferred to the F-35 Operations Center,” the JPO said.

Incorrect inventory data for complex assemblies continues to result in grounding conditions.

This particular deficiency involves supplies or components that, upon installation, are not actually listed and tracked in ALIS as designed. Those require specific, almost daily requests to software engineers to have data corrected in the system. While those requests can catch some problems, the issue is not always detected by the user.

These “holes,” as the JPO calls them, do not collect data on how parts are used after installation, which means a part might be breaking down from heavy use. Yet, that part won't be flagged by ALIS as an at-risk piece.

As a result, it's less likely that issues developing from wear and tear or a lack of replacement parts will be discovered until such an issue has become an acute problem, possibly leading to a grounding of the aircraft.

The issue was downgraded to a CAT 2 deficiency on Jan. 13, 2020, “due to ALIS data quality improvements that have been made in the two years since this DR [deficiency report] was written,” according to the JPO. “The quality improvements have reduced the frequency and magnitude of issues that have impacted operational units' abilities to quickly release aircraft for flight following maintenance.”

The F-35B and F-35C experienced incongruous lateral and longitudinal control response above a 20-degree angle of attack.

One of the most eye-opening issues identified in the initial report was that the F-35B and F-35C models used by the Marine Corps and Navy become difficult to control when operating above a 20-degree angle of attack — which would be seen in the extreme maneuvers a pilot might use in a dogfight or while avoiding a missile.

Pilots reported the aircraft experiencing unpredictable changes in pitch, as well as erratic yaw and rolling motions when coming in at that angle of attack..

“It has random oscillations, pitch and yaw issues above [its] 20-[degree angle of attack]," a longtime naval aviator told Defense News last year. "[So] if I had to perform the aircraft — if I had to maneuver to defeat a missile, maneuver to fight another aircraft, the plane could have issues moving. And if I turn around aggressively and get away from these guys and use the afterburner, [the horizontal tail and tail boom] start to melt or have issues.”

The issue was important enough that it accounted for two CAT 1 issues, one each for the two variants impacted by the design issue.

However, the JPO downgraded this issue to a CAT 2 on May 28, 2019, for the F-35C and on July 8, 2019, for the F-35B. The solution involves “improvements in flying qualities that were implemented in software. The improvements provide pilots with an intuitive reference indication for AOA [angle of attack], which allows pilots to more quickly optimize lateral maneuvering during air-to-air maneuvering. These software improvements have been released to all F-35 operators.”

There were unanticipated thrust limits in jetborne flight on hot days.

This particular issue only occurred once, but was so significant that it was identified in the original document as the “No. 1 priority” for the Marine Corps.

The issue was identified aboard the amphibious assault ship Essex, where a Marine pilot performed what is known as a “mode four” operation. That is where the jet enters hover mode near a landing spot, slides over to a target area and then vertically lands onto the ship. It's a key capability for the "B" model, which was designed for its short-takeoff-and-vertical-landing abilities.

The engine — working hard on a day that temperatures cracked 90 degrees Fahrenheit while trying to lift a plane that was heavier than most returning to base — wouldn't generate the needed thrust for a safe, ideal landing. The pilot managed to land, but the issue set off alarm bells in the Marine aviation community.

The JPO initially expected a fix for this issue to be out sometime in 2019, but it wasn't until March 2020 that a mix of nondescript “software updates and procedural adjustments” brought the “propulsion system performance back to original specified performance levels.”

https://www.defensenews.com/smr/hidden-troubles-f35/2020/04/24/five-f-35-issues-have-been-downgraded-but-they-remain-unsolved/

Sur le même sujet

  • Tribune : « Préservons l'industrie de Défense »

    26 janvier 2022 | International, Aérospatial, Naval, Terrestre, C4ISR, Sécurité

    Tribune : « Préservons l'industrie de Défense »

    Dans une tribune publiée par Les Echos, des élus locaux, dont, notamment, Xavier Bonnefont, maire d'Angoulême, Yann Galut, maire de Bourges, et François Cuillandre, maire de Brest, appellent à « préserver l'industrie de Défense ». Ils alertent sur le risque que représente le manque de financements : au-delà du rôle de l'Etat, le financement de l'innovation de Défense « repose aussi sur le financement bancaire, qui se réduit du fait de l'accumulation de normes internationales qui conduisent les banques et les fonds d'investissement à exclure certains secteurs, comme celui de la Défense ». Cette exclusion touche les grands groupes, mais surtout les startups, ETI et PME, observent-ils. Ils soulignent qu'« à côté de quelques groupes d'envergure internationale qui font la fierté de notre pays », la base industrielle et technologique de défense (BITD) française repose essentiellement sur des milliers de PME, ETI et TPE sur l'ensemble du territoire : « Chaque département accueille des entreprises du secteur de la Défense, soit un tissu de plus de 200 000 emplois de haute technicité, non délocalisables, qui contribuent positivement à la balance commerciale. Dans plusieurs régions, la Défense représente plus de 7% des emplois industriels ». Les élus appellent à « veiller impérativement à ne pas exclure des entreprises stratégiques qui bénéficient d'une avance technologique et sont le terreau de notre souveraineté nationale ».

  • HII Wins Navy Planning Yard Contract Worth a Potential $724 Million - Seapower

    11 juin 2021 | International, Naval

    HII Wins Navy Planning Yard Contract Worth a Potential $724 Million - Seapower

    PASCAGOULA, Miss. — Huntington Ingalls Industries’ Ingalls Shipbuilding division has been awarded a contract with a potential total value of $724 million for planning yard services in support of in-service amphibious ships, the company announced June 8.  “Ingalls has a...

  • Budget Shows Flightworthy Sixth-Generation Fighter Engines Ready By 2025

    3 août 2020 | International, Aérospatial

    Budget Shows Flightworthy Sixth-Generation Fighter Engines Ready By 2025

    Steve Trimble July 31, 2020 Details of the first of two mostly secret initiatives to support the U.S. Air Force's five-year-old pursuit of a sixth-generation successor to the Lockheed Martin F-22 are now released and reveal that a critical technology for the Next-Generation Air Dominance program could become flightworthy by mid-2025. GE Aviation and Pratt & Whitney are scheduled to complete separate competitive designs for a Next-Generation Adaptive Propulsion (NGAP) system by the second quarter of 2022 and finish assessments on a full-scale engine three years later, according to Air Force budget documents. The schedule and spending details on the NGAP appeared for the first time in the Air Force's budget justification documents for fiscal 2021 that were submitted to Congress in February, but passed unnoticed for several months. The Air Force awarded GE and Pratt each a $427 million contract to support the NGAP program, but the details were shrouded in budget documents within the related Adaptive Engine Transition Program (AETP), an unclassified effort to develop a reengining candidate for the Lockheed F-35. After Senate authorizers cited the Air Force's lack of transparency for justifying a $270 million budget cut for AETP this year, service officials decided to break out funding for the NGAP in budget documents. In fact, the NGAP program reappeared in the fiscal 2021 budget documents for the first time in more than six years. The Air Force has kept all details about the Next-Generation Air Dominance (NGAD) program highly secret since 2016, but there was a brief, two-year window in 2014-15 when senior defense officials provided information about the underlying technology development efforts. The NGAP was first referenced in testimony by Alan Shaffer before House Armed Services Committee in March 2014. Shaffer is now the deputy to Ellen Lord, undersecretary of defense for acquisition and sustainment. Six years ago, he was the principal deputy to the director for research and engineering. In that role, Shaffer introduced the NGAP as an enabler to the NGAD program, along with another, complementary initiative focused on new airframes. “This program will develop and fly two X-plane prototypes that demonstrate advanced technologies for future aircraft,” Shaffer said in 2014. “Teams will compete to produce the X-plane prototypes, one focused on future Navy operational capabilities, and the other on future Air Force operational capabilities.” A year later, Frank Kendall, then undersecretary of defense for acquisition, technology and logistics, elaborated on the Aerospace Innovation Initiative (AII). The development of the X-planes would be led by DARPA, he said. “To be competitive, the Navy and the Air Force each will have variants focused on their mission requirements,” Kendall said. “There will be a technology period leading up to development of the prototypes. This will lead to the systems that ultimately will come after the F-35.” The results of the AII program have not been released or even acknowledged by Air Force or defense officials since 2015, but the initiative suggests that one or two X-plane aircraft could be in testing now. Kendall's remarks to Congress in 2015 came a year before the Air Force received the results of an Enterprise Capability Collaboration Team on the Air Superiority 2030 Flight Plan, which urged the development of a family of systems anchored by a next-generation fighter to replace the F-22. The Flight Plan prompted the Air Force to commission an analysis of alternatives (AoA) in late 2016. The results of that study were originally scheduled to be released by the end of 2017, but the analysis continued until early 2019. Meanwhile, a 2015 presentation by the Air Force Research Laboratory showed a notional schedule for the NGAD program; a contract award to launch the engineering and manufacturing development (EMD) phase is set for fiscal 2023. As late as the Air Force's fiscal 2019 budget request, the financial resources devoted to the NGAD appeared to support that schedule: A significant increase in funding starts in fiscal 2023, and $13 billion is set aside overall between fiscal 2019 and 2023. Last year, however, as the results of the AoA study became available, the Air Force appeared to defer the launch of the EMD by at least a few years. The fiscal 2020 budget request included only $6.6 billion for the NGAD from fiscal 2020-24. Funding for the NGAD and NGAP programs is accounted for separately in Air Force budget documents. The fiscal 2021 budget justification documents reveal that the Air Force spent $106 million for the NGAP in fiscal 2019. Another $224 million is allocated to the NGAP this year. But the program has requested an additional $403 million in fiscal 2021, the budget documents show. “The Next-Generation Adaptive Propulsion effort consists of four phases: preliminary design, detailed design, engine fabrication and engine assessments,” the Air Force's budget documents state. “Program deliverables include military adaptive engine detailed design parameters and models, engine hardware (plus spare parts), matured technologies, major rig assessment data (controls, combustor, etc.), program reviews, and technology, affordability and sustainability studies for next generation fighter aircraft,” the documents add. https://aviationweek.com/defense-space/budget-policy-operations/budget-shows-flightworthy-sixth-generation-fighter-engines

Toutes les nouvelles