Posts
This morning, three publications reported more (and important) information about a report submitted to Acting Acquisition Czar Robert Kendall in November about the F-35. This "Quick Look Report" was previously reported by Bloomberg News (Tony Capaccio). Today's articles expand the coverage of the contents of the report. These articles by Jason Sherman and colleagues at Inside Defense, Bill Sweetman of the Ares Defense Technology Blog, and Bob Cox at the Fort Worth Star Telegram are below.
The new revelations are numerous and significant enough to call into question whether F-35 production should be suspended--if not terminated--even in the minds of today's senior managers in the Pentagon. The revelations include, but are not limited to "unsatisfactory progress and the likelihood of severe operational impacts for survivability, lethality, air vehicle performance, and employment." Performance vis-à-vis so called "legacy" aircraft is seriously questioned, and the individual deficiencies are sometimes so remarkable as to call into question the competence of the designers at Lockheed-Martin, to say nothing of the cost to repair the deficiencies. For example, the naval variant is now incapable of landing or carriers due to the inability of the arresting hook to capture an arresting cable on the carrier deck. And, there are more hard to conceive deficiencies, including airframe buffeting at different angles of attack. Moreover, as the report points out, these problems are appearing only after the easy phases of the test flights. The more exacting/demanding test flights are yet to even start. What unpleasant surprises do they hold?
The report frequently repeats the assertion that nothing so serious was found to "preclude further production." Read the report and decide for yourself if the report supports that conclusion, or actually the reverse. In fact, the oft repeated assurance that nothing too serious is uncovered was, in fact, added on by some in a rather pathetic attempt to convert this report into mush.
Thanks to POGO, find the full report at http://www.pogo.org/resources/
Find today's stories below:
From Jason Sherman at Inside Defense:
DefenseAlert
Concerns About JSF's Lethality, Survivability Triggered 'Concurrency Risk' Review
Posted on InsideDefense.com: December 13, 2011
An internal Defense Department report detailing major, unresolved design problems with the Joint Strike Fighter, which recommends that DOD reconsider its F-35 procurement and production plans, was triggered by U.S. and British operational testers who, the report states, had "significant concerns" about the F-35's lethality, survivability and air performance characteristics.
The testers' October 20, 2011 findings, "Operational Assessment OT-IIE," prompted the Pentagon's acting acquisition executive, Frank Kendall, to commission an independent assessment of the risks associated with the F-35 program's plan to simultaneously produce new aircraft while still refining the aircraft's design.
Some findings of the Kendall-directed assessment -- "F-35 Joint Strike Fighter Concurrency Quick Look Review," dated November 29 -- were reported by Bloomberg on December 6. The chief aim of the effort was to size up the "concurrency risk" of the JSF program, which the report defines as the potential for significant design changes to the F-35 "in order to assess the risk associated with modification to aircraft being produced while the design is still being tested and changed."
The report, prepared by five senior officials from across the Pentagon's acquisition directorate, determined that "no fundamental design risks" were identified to warrant halting production.
Still, the assessment details five engineering challenges "where major consequence issues have been identified, but root cause, corrective action or fix are still in development." These include problems with the Helmet Mounted Display System, the fuel dump subsystem, the integrated power package and the arresting hook system on the variant designed for aircraft carrier launches and landings.
These engineering difficulties came to the attention of Pentagon leaders in part because of a broader set of concerns with the F-35 program raised by commanders of the Air Force Operational Test and Evaluation Center, the Navy Operational Test and Evaluation Force and the Untied Kingdom's Royal Air Force Air Warfare Center in their report this fall.
The "quick-look review" described the findings of the three operational testers.
Following a year-long assessment that aimed to size up the F-35’s progress toward operational effectiveness suitability -- as well as mission capability -- the operational testers concluded that the Joint Strike Fighter program was "not making sufficient progress toward meeting operational effectiveness criteria" across a range of areas, according to the Pentagon's November 29 report.
The testers' assessment, dubbed OA OT-IIE for short, "cited unsatisfactory progress towards meeting performance requirements for the air-to-surface (A/S) attack mission capability and survivability." Among the main concerns were the aircraft's night-vision capability, unresolved problems with the helmet-mounted display and unnamed classified "survivability" issues.
Testers also reported "significant concerns" with "aircraft performance characteristics, particularly transonic roll-off and buffet, as well as maneuvering performance," according to the Pentagon's characterization of their report.
In addition, the testers -- concerned in part by air-vehicle performance and questions about the ability to launch air-to-air missiles -- raised numerous questions about the F-35's ability to prevail in a contest against enemy aircraft or air-defense systems.
"The operational testers cited unsatisfactory progress and the likelihood of severe operational
impacts for survivability, lethality, air vehicle performance, and employment," according to the Pentagon report.
The JSF's electronic warfare capabilities were also questioned by the testers. In particular, they expressed concern over the stealthy fighter's ability to suppress and defeat enemy air defenses, according to the Pentagon's report, which cites "classified lethality and survivability issues" as well.
In addition, concerns about operational and sustainment issues were raised by the U.S. and U.K. testing officials.
The OA OT-IIE "concluded with an assessment of the F-35 system’s readiness to forward base, deploy, and retrograde; to generate missions in the intended operating environment; to train pilots and personnel; and support flight operations," according to the Pentagon summary of the tester's report. "Chief among their concerns were the readiness of the [Autonomic Logistics Information System] and its multiplicity of configurations; the thermal management system; the integrated power package (IPP); the overall logistics footprint and systems interoperability; progress on the HMD; and low observable (LO) maintenance."
While the Pentagon's "quick-look report" validated these concerns as a source of concurrency risk in the F-35 program, that study also found that issues raised by testers about the development of other planned F-35 capabilities -- close-air support, combat search and rescue and reconnaissance -- were not sources of concurrency risk.
-- Jason Sherman
Concerns About JSF's Lethality, Survivability Triggered 'Concurrency Risk' Review
Posted on InsideDefense.com: December 13, 2011
An internal Defense Department report detailing major, unresolved design problems with the Joint Strike Fighter, which recommends that DOD reconsider its F-35 procurement and production plans, was triggered by U.S. and British operational testers who, the report states, had "significant concerns" about the F-35's lethality, survivability and air performance characteristics.
The testers' October 20, 2011 findings, "Operational Assessment OT-IIE," prompted the Pentagon's acting acquisition executive, Frank Kendall, to commission an independent assessment of the risks associated with the F-35 program's plan to simultaneously produce new aircraft while still refining the aircraft's design.
Some findings of the Kendall-directed assessment -- "F-35 Joint Strike Fighter Concurrency Quick Look Review," dated November 29 -- were reported by Bloomberg on December 6. The chief aim of the effort was to size up the "concurrency risk" of the JSF program, which the report defines as the potential for significant design changes to the F-35 "in order to assess the risk associated with modification to aircraft being produced while the design is still being tested and changed."
The report, prepared by five senior officials from across the Pentagon's acquisition directorate, determined that "no fundamental design risks" were identified to warrant halting production.
Still, the assessment details five engineering challenges "where major consequence issues have been identified, but root cause, corrective action or fix are still in development." These include problems with the Helmet Mounted Display System, the fuel dump subsystem, the integrated power package and the arresting hook system on the variant designed for aircraft carrier launches and landings.
These engineering difficulties came to the attention of Pentagon leaders in part because of a broader set of concerns with the F-35 program raised by commanders of the Air Force Operational Test and Evaluation Center, the Navy Operational Test and Evaluation Force and the Untied Kingdom's Royal Air Force Air Warfare Center in their report this fall.
The "quick-look review" described the findings of the three operational testers.
Following a year-long assessment that aimed to size up the F-35’s progress toward operational effectiveness suitability -- as well as mission capability -- the operational testers concluded that the Joint Strike Fighter program was "not making sufficient progress toward meeting operational effectiveness criteria" across a range of areas, according to the Pentagon's November 29 report.
The testers' assessment, dubbed OA OT-IIE for short, "cited unsatisfactory progress towards meeting performance requirements for the air-to-surface (A/S) attack mission capability and survivability." Among the main concerns were the aircraft's night-vision capability, unresolved problems with the helmet-mounted display and unnamed classified "survivability" issues.
Testers also reported "significant concerns" with "aircraft performance characteristics, particularly transonic roll-off and buffet, as well as maneuvering performance," according to the Pentagon's characterization of their report.
In addition, the testers -- concerned in part by air-vehicle performance and questions about the ability to launch air-to-air missiles -- raised numerous questions about the F-35's ability to prevail in a contest against enemy aircraft or air-defense systems.
"The operational testers cited unsatisfactory progress and the likelihood of severe operational
impacts for survivability, lethality, air vehicle performance, and employment," according to the Pentagon report.
The JSF's electronic warfare capabilities were also questioned by the testers. In particular, they expressed concern over the stealthy fighter's ability to suppress and defeat enemy air defenses, according to the Pentagon's report, which cites "classified lethality and survivability issues" as well.
In addition, concerns about operational and sustainment issues were raised by the U.S. and U.K. testing officials.
The OA OT-IIE "concluded with an assessment of the F-35 system’s readiness to forward base, deploy, and retrograde; to generate missions in the intended operating environment; to train pilots and personnel; and support flight operations," according to the Pentagon summary of the tester's report. "Chief among their concerns were the readiness of the [Autonomic Logistics Information System] and its multiplicity of configurations; the thermal management system; the integrated power package (IPP); the overall logistics footprint and systems interoperability; progress on the HMD; and low observable (LO) maintenance."
While the Pentagon's "quick-look report" validated these concerns as a source of concurrency risk in the F-35 program, that study also found that issues raised by testers about the development of other planned F-35 capabilities -- close-air support, combat search and rescue and reconnaissance -- were not sources of concurrency risk.
-- Jason Sherman
From Bill Sweetman at the Ares Defense Technology blog at http://www.aviationweek.com/
JSF - What's Really Happening
When the Joint Strike Fighter team told Guy Norris about the jet's first run to its Mach 1.6 design speed, a couple of minor facts slipped their minds. Nobody remembered that the jet had landed (from either that sortie or another run to Mach 1.6) with "peeling and bubbling" of coatings on the horizontal tails and damage to engine thermal panels. Or that the entire test force was subsequently limited to Mach 1.0.
But selective amnesia is not even one of five "major consequence" problems that have already surfaced with the JSF and are disclosed by a top-level Pentagon review obtained by Ares. Those issues affect flight safety, the basic cockpit design, the carrier suitability of the F-35C and other aspects of the program have been identified, and no fixes have been demonstrated yet. Three more "major consequence" problems are "likely" to emerge during tests, including high buffet loads and airframe fatigue.
Update: POGO has the full report here.
Experience from flight testing has eviscerated the argument that the F-35 program architects used to support high concurrency, with fat production contracts early in the test program: that modeling and simulation had advanced to the point where problems would be designed out of the hardware. In fact, the F-35 is having just as many problems as earlier programs, which means that there is no reason to expect that it will not continue to do so.
The "quick look review" (QLR) panel was chartered by acting Pentagon acquisition boss Frank Kendall on Oct. 28, eight days after top U.S. Air Force, Navy and U.K. Royal Air Force operational test force commanders jointly expressed their concern that the F-35 would not be ready to start initial operational testing in 2015, as envisaged in the delayed test program adopted in January.
Kendall was looking for an assessment of test progress, as well as a look at "concurrency risk" - the concern that problems discovered in testing will result in expensive modifications to aircraft that are produced before the fixes can be designed, tested and implemented in production.
The QLR was submitted on Nov. 29, before Navy Vice Adm. Dave Venlet, the JSF program director, disclosed some of the fatigue issues in interviews with AOLDefense. Its existence and some of its findings were reported by Bloomberg's Tony Capaccio early last week.
The most positive thing that the QLR has to say about the program is that the team "identified no fundamental design risks sufficient to preclude further production." That is, they don't say that the program should be terminated, or that production should be halted until problems are fixed. But the team concludes:
Since flight testing started to pick up speed in June 2010, 725 engineering change requests have been initiated, of which 148 are ready to incorporate. On average, it takes 18-24 months between the identification of a change and its implementation in production. JSF production orders started three to four years earlier than other fighters, and even under the current plan, close to 200 aircraft will be on order by the halfway point in flight testing.
Many of the issues described by the QLR have been reported, but not in detail. Others have been played down by the program. The following are four of the "big five" issues that have already surfaced. (The fifth is classified, but dollars to doughnuts it has something to do with stealth.)
We knew that the helmet-mounted display was in trouble. A simpler alternate HMD was ordered from BAE Systems in September, but it does not meet the requirement for "through the airplane" zero-light visibility provided by the electro-optical distributed aperture system. (Yes, that EO-DAS, that makes maneuvering irrelevant.)
Today, the killer problem with EO-DAS is latency: the image in the helmet lags 130 milliseconds behind sightline movement where the spec is under 40 ms. (So the video is where the pilot's head was pointed an eighth of a second ago.) That can't be fixed without changing the JSF's integrated core processor - the jet's central brain - and the EO-DAS sensors. Even the backup helmet faces buffet and latency issues, simply for symbology.
The underwing fuel dump system on the JSF doesn't get fuel clear of the aircraft surfaces, so that fuel accumulates in the flaperon and may get into the integrated power package (IPP) exhaust. That creates a fire hazard, particularly on a ship deck after landing. Fuel dumping has been banned except in an emergency. Two unsuccessful modifications have been tried on the F-35B.
The IPP - the cause of a grounding this summer, after a "catastrophic failure" caused IPP parts to puncture a fuel tank - is turning out to be unreliable. It's supposed to last 2,200 hours, but so far in the flight test program, 16 IPPs have been removed and replaced - a process that takes two days of 24-hour work.
The arrester hook issue has been reported. In the first round of tests, the hook failed to catch the wire once. The QLR notes that tests of a minimal modification - a reprofiled hook with different damper settings - set for April "represent only the initial stages leading into full carrier suitability demonstrations."
Studies are already underway of changing the hook's location - the basic problem is that the designers put the hook closer behind the main landing gear than that of any current or recent Navy aircraft, even the tailless X-47B - but that will have "major, direct primary and secondary structural impacts".
The QLR report predicts more problems, based on experience so far, historical data, and the collapse of the "test is validation" orthodoxy.
F-35 flight tests have not gone beyond 20 degrees angle of attack, and higher-than-predicted buffet loads have been experienced. So far, severity has been similar to current aircraft but it is experienced over a large part of the envelope. Exploration of the high-AoA envelope does not start until the fall of 2012 and full results will not be available until 2014. Excess buffet can accelerate airframe fatigue, and induces jitter in the HMD.
One editorial observation, not from the report: aerodynamic issues are a challenge on a stealth aircraft because some of the standard fixes - fences, strakes and vortex trippers, for instance - can't be used.
Other risks are individually less severe but cumulatively could result in substantial modifications. They include thermal issues - like the current speed restriction - and an untested lightning protection system, which at least until late 2012 means that the aircraft is not allowed within 25 nm of predicted lightning. (That is expected to cancel 25-50% of training events at Eglin AFB.) Weight margins for all versions are paper-thin.
The full QLR is densely packed and makes fascinating reading. Personal view? What keeps going through my mind is Gus McCrae from Larry McMurtry's Lonesome Dove, after one of the Hat Creek outfit has ridden into a nest of water moccasins:
"Eight sets of bites, not countin' the legs. Ain't no point in countin' the legs."
But selective amnesia is not even one of five "major consequence" problems that have already surfaced with the JSF and are disclosed by a top-level Pentagon review obtained by Ares. Those issues affect flight safety, the basic cockpit design, the carrier suitability of the F-35C and other aspects of the program have been identified, and no fixes have been demonstrated yet. Three more "major consequence" problems are "likely" to emerge during tests, including high buffet loads and airframe fatigue.
Update: POGO has the full report here.
Experience from flight testing has eviscerated the argument that the F-35 program architects used to support high concurrency, with fat production contracts early in the test program: that modeling and simulation had advanced to the point where problems would be designed out of the hardware. In fact, the F-35 is having just as many problems as earlier programs, which means that there is no reason to expect that it will not continue to do so.
The "quick look review" (QLR) panel was chartered by acting Pentagon acquisition boss Frank Kendall on Oct. 28, eight days after top U.S. Air Force, Navy and U.K. Royal Air Force operational test force commanders jointly expressed their concern that the F-35 would not be ready to start initial operational testing in 2015, as envisaged in the delayed test program adopted in January.
Kendall was looking for an assessment of test progress, as well as a look at "concurrency risk" - the concern that problems discovered in testing will result in expensive modifications to aircraft that are produced before the fixes can be designed, tested and implemented in production.
The QLR was submitted on Nov. 29, before Navy Vice Adm. Dave Venlet, the JSF program director, disclosed some of the fatigue issues in interviews with AOLDefense. Its existence and some of its findings were reported by Bloomberg's Tony Capaccio early last week.
The most positive thing that the QLR has to say about the program is that the team "identified no fundamental design risks sufficient to preclude further production." That is, they don't say that the program should be terminated, or that production should be halted until problems are fixed. But the team concludes:
"The combined impact of these issues results in a lack of confidence in the design stability...this lack of confidence, in conjunction with the concurrency driven consequences of the required fixes, supports serious reconsideration of procurement and production planning...The QLR team recommends that further decisions about F-35 concurrent production be event-driven."
Since flight testing started to pick up speed in June 2010, 725 engineering change requests have been initiated, of which 148 are ready to incorporate. On average, it takes 18-24 months between the identification of a change and its implementation in production. JSF production orders started three to four years earlier than other fighters, and even under the current plan, close to 200 aircraft will be on order by the halfway point in flight testing.
Many of the issues described by the QLR have been reported, but not in detail. Others have been played down by the program. The following are four of the "big five" issues that have already surfaced. (The fifth is classified, but dollars to doughnuts it has something to do with stealth.)
We knew that the helmet-mounted display was in trouble. A simpler alternate HMD was ordered from BAE Systems in September, but it does not meet the requirement for "through the airplane" zero-light visibility provided by the electro-optical distributed aperture system. (Yes, that EO-DAS, that makes maneuvering irrelevant.)
Today, the killer problem with EO-DAS is latency: the image in the helmet lags 130 milliseconds behind sightline movement where the spec is under 40 ms. (So the video is where the pilot's head was pointed an eighth of a second ago.) That can't be fixed without changing the JSF's integrated core processor - the jet's central brain - and the EO-DAS sensors. Even the backup helmet faces buffet and latency issues, simply for symbology.
The underwing fuel dump system on the JSF doesn't get fuel clear of the aircraft surfaces, so that fuel accumulates in the flaperon and may get into the integrated power package (IPP) exhaust. That creates a fire hazard, particularly on a ship deck after landing. Fuel dumping has been banned except in an emergency. Two unsuccessful modifications have been tried on the F-35B.
The IPP - the cause of a grounding this summer, after a "catastrophic failure" caused IPP parts to puncture a fuel tank - is turning out to be unreliable. It's supposed to last 2,200 hours, but so far in the flight test program, 16 IPPs have been removed and replaced - a process that takes two days of 24-hour work.
The arrester hook issue has been reported. In the first round of tests, the hook failed to catch the wire once. The QLR notes that tests of a minimal modification - a reprofiled hook with different damper settings - set for April "represent only the initial stages leading into full carrier suitability demonstrations."
Studies are already underway of changing the hook's location - the basic problem is that the designers put the hook closer behind the main landing gear than that of any current or recent Navy aircraft, even the tailless X-47B - but that will have "major, direct primary and secondary structural impacts".
The QLR report predicts more problems, based on experience so far, historical data, and the collapse of the "test is validation" orthodoxy.
F-35 flight tests have not gone beyond 20 degrees angle of attack, and higher-than-predicted buffet loads have been experienced. So far, severity has been similar to current aircraft but it is experienced over a large part of the envelope. Exploration of the high-AoA envelope does not start until the fall of 2012 and full results will not be available until 2014. Excess buffet can accelerate airframe fatigue, and induces jitter in the HMD.
One editorial observation, not from the report: aerodynamic issues are a challenge on a stealth aircraft because some of the standard fixes - fences, strakes and vortex trippers, for instance - can't be used.
Other risks are individually less severe but cumulatively could result in substantial modifications. They include thermal issues - like the current speed restriction - and an untested lightning protection system, which at least until late 2012 means that the aircraft is not allowed within 25 nm of predicted lightning. (That is expected to cancel 25-50% of training events at Eglin AFB.) Weight margins for all versions are paper-thin.
The full QLR is densely packed and makes fascinating reading. Personal view? What keeps going through my mind is Gus McCrae from Larry McMurtry's Lonesome Dove, after one of the Hat Creek outfit has ridden into a nest of water moccasins:
"Eight sets of bites, not countin' the legs. Ain't no point in countin' the legs."
From Bob Cox at the Forth Worth Star Telegram at
December 13, 2011
Internal Pentagon report finds major problems with F-35 performance and components
The internal report marked "For Official Use Only" is written in carefully couched language, but clearly sounds alarms that some very large, troubling and costly to resolve technological and performance issues lie ahead for the already troubled and massively over budget F-35.
The report prepared by a team of senior Pentagon technical, engineering and test experts found that "unsatisfactory progress" had been made in development and testing of the F-35 in nearly all of the air combat roles that it is designed to perform.
In ground attack roles the report cites concerns about "mission capability and survivability" and "certain classified survivability issues."
Although most of the really challenging flight testing of the F-35 in high speed, air combat regimes has yet to be performed, the Pentagon and military officials overseeing testing "expressed significant concerns with aircraft performance characteristics."
The "Quick Look Review" report, 50-plus pages including numerous charts, illustrations and detailed projections, was prepared just since mid-October by a team headed by five senior Pentagon officials with expertise in weapons evaluation testing and engineering.
It was requested by Frank Kendall, acting undersecretary of defense for weapons acquisition and development. Kendall asked for the report to assess the state of F-35 development so defense officials could decide whether and how many planes they should agree to buy while development was still under way.
The report essentially concludes that highly sophisticated design and modeling technology has failed in predicting and preventing problems with the design, production and performance of the aircraft and its critical combat systems.
In no case does the report state that any of the problems cannot be overcome or that the F-35 will be unable fulfill its intended missions, but it does strongly suggest the worst of the problems may not yet be known and that the fixes will take years and vast new sums of money.
The report authors say as a result of the combined issues the Pentagon should go very slowly in buying more jets.
"The combined impact of these issues results in a lack of confidence in the design stability...this lack of confidence, in conjunction with the concurrency driven consequences of the required fixes, supports serious reconsideration of procurement and production planning...The QLR team recommends that further decisions about F-35 concurrent production be event-driven."
Vice Admiral David Venlet discussed some of the report's conclusions about the problems created by concurrent development and production in a recent interview published by AOL Defense but did not hint at some of the detailed performance problems and the severity. Bloomberg first obtained a copy of the report and reported some of the issues.
Major areas of concern include:
* Worse than predicted buffeting of the aircraft in high speed and maneuvering modes with the most stringent testing in combat-like situations yet to be done. The result is already seen and predicted further accelerated wear and tear on the aircraft, cracks in the structural frame.
* The high tech helmet-mounted-display that is supposed to allow the pilot to be aware of potential threats and attack targets at night or in bad weather performs badly and its night vision capability is far less than existing systems used by pilots in existing aircraft. The buffeting of the aircraft in flight makes the helmet-mounted-display problems worse.
* The integrated power package that provides backup electrical power, controls much of the aircraft's avionics and the primary oxygen supply and cockpit pressurization has proven horribly unreliable.
* The tailhook arrester on the F-35C for carrier landings failed in every test to catch the arresting cables that yank jets to a halt. A new tailhook design is beign readied for testing early next year but the report suggests that the problem may lie with the basic design of the aircraft itself and fixing it could require a major redesign of the F-35C structure.
- Bob Cox
More from Inside Defense
JSF Report: Helmet Display Less Functional Than Current Technology
InsideDefense.com: December 13, 2011 -- A Defense Department report analyzing the concurrency-related risks to the Joint Strike Fighter program concludes that the aircraft's next-generation helmet display continues to suffer from deficiencies that make it less functional than legacy equipment, and a proper corrective action has yet to be identified.
The Generation II Helmet-Mounted Display System (HMDS), which is being developed by Lockheed Martin subcontractor Vision Systems International, is one of five areas of the F-35 "where major consequence issues have been identified, but root cause, corrective action or fix effectivity are still in development," according to the Nov. 29 DOD report, "F-35 Joint Strike Fighter Concurrency Quick Look Review." The report, provided to InsideDefense.com by a non-DOD source, was authored by five officials from the Office of the Secretary of Defense after a two-week review conducted late this fall.
Some findings of the document were first reported by Bloomberg on Dec. 6.
The report calls the HMDS a "program-level high development risk" and picks out three major problems: night-vision acuity, display jitter and Electro-Optical Distributed Aperture System (EO DAS) image display latency. Collectively, the report says, they amount to a major technical risk requiring modifications to the overall system architecture.
"The HMD system is integral to pilot safety, situational awareness, and tactical effectiveness and faces hardware/architecture changes to meet full requirements," the report reads. The helmet display has previously been identified as a key challenge of achieving F-35 cost and schedule limits by DOD's lead tester, Michael Gilmore.
According to the document, the F-35's display system provides poor night vision acuity, worse even than the quality provided by legacy night-vision goggles (NVGs). The night-vision camera on the HMDS is able to provide roughly 20/70 acuity, the report states, while NVGs provide approximately 20/25 acuity. JSF program officials are considering a secondary helmet display system that would utilize NVGs in place of a camera; this would provide acceptable night-vision acuity, but would be totally lacking in other areas, such as DAS video capability, the report states. Alternatively, an upgrade to the HMDS camera is being developed, but it is still not expected to achieve legacy quality and is not yet available for testing.
The poor vision acuity on the HMDS is negatively affecting F-35 testing progress by limiting what kind of test points pilots can go after. In a Dec. 6 interview with InsideDefense.com, Lt. Col. Hank Griffiths, the Air Force's lead JSF test pilot, said the program had yet to start flying at night, and that when it does begin night flights in 2012, it will have to stay away from "military utility" operations until a night-vision capability becomes available. In the meantime, the test envelope will involve operations like flying at night to analyze the F-35's interior lighting.
Grrifiths said the JSF program's acuity requirement on the HMDS is 20/40.
A second key issue on the HMDS is display jitter caused in part by worse-than-expected vibrations known as aircraft buffet, and buffet is likely to prove to have an increasingly detrimental effect as the F-35's test envelope is expanded to include more stressful maneuvers like high-angle-of-attack operations.
The report states that aircraft buffet induces display jitter, "making symbology unreadable under those conditions." Problematically, those conditions could be present while pilots react to air-to-air or surface-to-air threats as well as during weapons employment operations. A potential fix, a new part called a Micro Inertial Measurement Unit, has not yet been tested.
The report identifies buffet as one of several areas where potentially major consequences are likely to be discovered through further testing. Buffet not only causes a bumpier ride for pilots, but can put increased stress on the F-35's airframe and require structural retrofits or an increased rate of inspections; the full extent of buffet issues will not be known until 2014. Griffiths said last week that testing has shown that some unplanned loads and buffeting are occurring under certain conditions.
The third HMDS issue raised in the report is latency, essentially delays in the download and appearance of images, on the Northrop-Grumman-built EO DAS that is "detracting from mission capability." The report explains that the HMDS is not meeting latency requirements, and that a full-motion simulator study to be conducted in 2012 to characterize the effects of these delays will be only marginally useful because it cannot account for the effect of buffeting and G-forces experienced in flight. As such, "the effects of latency may not be fully understood until the chosen corrective action is flight tested."
According to Griffiths, pilots at Edwards Air Force Base, CA, have not experienced major latency issues during daytime operations.
Griffiths added that testers at other locations have had a problem with the fit of the helmet, but that complaint has not been cited at Edwards AFB. Poor helmet fit was one of several issues -- including buffet and problems with camera hardware -- described by Gilmore in testimony before the Senate Armed Services Committee in May, but it is not included in the report.
"Problems [on the HMDS] include integration of the night vision capability, symbology jitter, and latency," Gilmore wrote at the time. "These stem in turn from problems with camera hardware, insufficient computer processing power, inaccurate head position tracking, and poor helmet fit, complicated by vibration-inducing airframe buffet experienced at high angles-of-attack in some dynamic maneuvering regimes." -- Gabe Starosta
Some findings of the document were first reported by Bloomberg on Dec. 6.
The report calls the HMDS a "program-level high development risk" and picks out three major problems: night-vision acuity, display jitter and Electro-Optical Distributed Aperture System (EO DAS) image display latency. Collectively, the report says, they amount to a major technical risk requiring modifications to the overall system architecture.
"The HMD system is integral to pilot safety, situational awareness, and tactical effectiveness and faces hardware/architecture changes to meet full requirements," the report reads. The helmet display has previously been identified as a key challenge of achieving F-35 cost and schedule limits by DOD's lead tester, Michael Gilmore.
According to the document, the F-35's display system provides poor night vision acuity, worse even than the quality provided by legacy night-vision goggles (NVGs). The night-vision camera on the HMDS is able to provide roughly 20/70 acuity, the report states, while NVGs provide approximately 20/25 acuity. JSF program officials are considering a secondary helmet display system that would utilize NVGs in place of a camera; this would provide acceptable night-vision acuity, but would be totally lacking in other areas, such as DAS video capability, the report states. Alternatively, an upgrade to the HMDS camera is being developed, but it is still not expected to achieve legacy quality and is not yet available for testing.
The poor vision acuity on the HMDS is negatively affecting F-35 testing progress by limiting what kind of test points pilots can go after. In a Dec. 6 interview with InsideDefense.com, Lt. Col. Hank Griffiths, the Air Force's lead JSF test pilot, said the program had yet to start flying at night, and that when it does begin night flights in 2012, it will have to stay away from "military utility" operations until a night-vision capability becomes available. In the meantime, the test envelope will involve operations like flying at night to analyze the F-35's interior lighting.
Grrifiths said the JSF program's acuity requirement on the HMDS is 20/40.
A second key issue on the HMDS is display jitter caused in part by worse-than-expected vibrations known as aircraft buffet, and buffet is likely to prove to have an increasingly detrimental effect as the F-35's test envelope is expanded to include more stressful maneuvers like high-angle-of-attack operations.
The report states that aircraft buffet induces display jitter, "making symbology unreadable under those conditions." Problematically, those conditions could be present while pilots react to air-to-air or surface-to-air threats as well as during weapons employment operations. A potential fix, a new part called a Micro Inertial Measurement Unit, has not yet been tested.
The report identifies buffet as one of several areas where potentially major consequences are likely to be discovered through further testing. Buffet not only causes a bumpier ride for pilots, but can put increased stress on the F-35's airframe and require structural retrofits or an increased rate of inspections; the full extent of buffet issues will not be known until 2014. Griffiths said last week that testing has shown that some unplanned loads and buffeting are occurring under certain conditions.
The third HMDS issue raised in the report is latency, essentially delays in the download and appearance of images, on the Northrop-Grumman-built EO DAS that is "detracting from mission capability." The report explains that the HMDS is not meeting latency requirements, and that a full-motion simulator study to be conducted in 2012 to characterize the effects of these delays will be only marginally useful because it cannot account for the effect of buffeting and G-forces experienced in flight. As such, "the effects of latency may not be fully understood until the chosen corrective action is flight tested."
According to Griffiths, pilots at Edwards Air Force Base, CA, have not experienced major latency issues during daytime operations.
Griffiths added that testers at other locations have had a problem with the fit of the helmet, but that complaint has not been cited at Edwards AFB. Poor helmet fit was one of several issues -- including buffet and problems with camera hardware -- described by Gilmore in testimony before the Senate Armed Services Committee in May, but it is not included in the report.
"Problems [on the HMDS] include integration of the night vision capability, symbology jitter, and latency," Gilmore wrote at the time. "These stem in turn from problems with camera hardware, insufficient computer processing power, inaccurate head position tracking, and poor helmet fit, complicated by vibration-inducing airframe buffet experienced at high angles-of-attack in some dynamic maneuvering regimes." -- Gabe Starosta
Report: F-35C Arresting Hook Problems Could Require Aircraft Redesign
InsideDefense.com: December 13, 2011 -- The arresting hook system on the carrier variant of the F-35 Joint Strike Fighter is too short to reliably grab the cable on carrier decks upon landing and will require extensive modifications to fix -- and the aircraft may need a structural redesign if those don't work, according to an internal report on JSF concurrency dated Nov. 29 and provided to InsideDefense.com by a non-Defense Department source.
The report, "F-35 Joint Strike Fighter Concurrency Quick Look Review," was authored by five senior defense officials. Some findings of the document were first reported by Bloomberg on Dec. 6.
The report paints a stark picture of a program still fraught with major risks after years of setbacks.
Among them is the arresting hook system (AHS) for the F-35C, which failed on all eight attempts to connect with the cable in recent roll-in arrestment testing at Naval Air Warfare Center Aircraft Division Lakehurst, NJ. And, with rolling engagements looming in April leading into full carrier suitability demonstrations of the F-35C, the report states that the program doesn't know how significant of a redesign will be needed.
"There are significant issues with respect to how the CV variant's AHS interoperates with aircraft carrier-based MK-7 arresting gear," the report states. "Root cause analysis identified three key AHS design issues: (1) the aircraft geometry has a relatively short distance between the aircraft's main landing gear tires and tailhook point (when lowered), (2) tailhook point design was overemphasized for cable-shredding features versus ability to scoop low-positioned cables, and (3) tailhook hold-down damper performance is ineffective to support damping of small bounces relative to runway/deck surface profiles."
At the heart of the issue is the fact that the F-35C's main landing gear to tailhook point distance is just 7.1 feet -- less than half as long as that of the F/A-18E/F Super Hornet, which stretches out to 18.2 feet. This is a problem because when the landing gear of the aircraft rolls over the cable on the carrier deck, the cable "lies nearly flat on the deck," the report notes. The more distance between the landing gear and the trailing tailhook, the more time the cable has to respond and flex back into its original position, allowing the tailhook to more easily scoop up the cable.
An additional problem has to do with how the hold-down damper was designed, which causes the tailhook to "bounce excessively," further contributing to the poor performance of the arresting gear.
Program officials are scrambling to modify the tailhook to solve the issues, and they hope to have a fix in place once rolling engagements begin at Lakehurst in April, according to the report.
"The proposed hook redesign . . . both reduces the blunt-face geometry with a more pointed front end and lowers its apex point by 0.5 inches (68 percent) such that it is now below the arresting gear cable centerline to better enable scooping performance," the report states. "The proposed hold-down damper redesign will consist of modifications to the AHS actuator damper such that a lesser number of orifices will temper tailhook bounce dynamics."
The program will conduct a probability-of-engagement analysis of the redesigned components sometime this month, and following a successful design review, "the plan is to manufacture the redesigned components and then conduct rolling engagements" at Lakehurst, the report adds.
However, the report notes that a redesign of just the tailhook may not be possible, and, in a worst-case scenario, a major structural redesign of the aircraft would be necessary.
"With corrective action still in development, the AHS is considered an area of major consequence," the report notes. "If the proposed redesigned components do not prove to be compatible with MK-7 arresting gear, then significant redesign impacts will ensue. Accordingly, the program is conducting a formal trade study to assess options beyond AHS redesign."
The report states that one of the options is to adjust the location of the AHS on the airframe, but "since arrestment loads are significant and the aircraft has certain constraints with respect to engine location and survivability considerations, any readjustment of AHS location will have major, direct primary and secondary structure impacts."
Program officials don't have complete information on the problem and won't know just how significant the AHS issue is for some time because the April rolling engagements are just the initial stages or arrestment testing before carrier suitability demonstrations, according to the report.
"This issue represents a major concurrency risk which would have a significant retrofit impact to [low-rate initial production] aircraft already delivered, a large re-adjustment to the current F-35C production process build-up flow and, in many respects, invalidate previously obtained developmental test and evaluation data," the report states. -- Dan Taylor
The report paints a stark picture of a program still fraught with major risks after years of setbacks.
Among them is the arresting hook system (AHS) for the F-35C, which failed on all eight attempts to connect with the cable in recent roll-in arrestment testing at Naval Air Warfare Center Aircraft Division Lakehurst, NJ. And, with rolling engagements looming in April leading into full carrier suitability demonstrations of the F-35C, the report states that the program doesn't know how significant of a redesign will be needed.
"There are significant issues with respect to how the CV variant's AHS interoperates with aircraft carrier-based MK-7 arresting gear," the report states. "Root cause analysis identified three key AHS design issues: (1) the aircraft geometry has a relatively short distance between the aircraft's main landing gear tires and tailhook point (when lowered), (2) tailhook point design was overemphasized for cable-shredding features versus ability to scoop low-positioned cables, and (3) tailhook hold-down damper performance is ineffective to support damping of small bounces relative to runway/deck surface profiles."
At the heart of the issue is the fact that the F-35C's main landing gear to tailhook point distance is just 7.1 feet -- less than half as long as that of the F/A-18E/F Super Hornet, which stretches out to 18.2 feet. This is a problem because when the landing gear of the aircraft rolls over the cable on the carrier deck, the cable "lies nearly flat on the deck," the report notes. The more distance between the landing gear and the trailing tailhook, the more time the cable has to respond and flex back into its original position, allowing the tailhook to more easily scoop up the cable.
An additional problem has to do with how the hold-down damper was designed, which causes the tailhook to "bounce excessively," further contributing to the poor performance of the arresting gear.
Program officials are scrambling to modify the tailhook to solve the issues, and they hope to have a fix in place once rolling engagements begin at Lakehurst in April, according to the report.
"The proposed hook redesign . . . both reduces the blunt-face geometry with a more pointed front end and lowers its apex point by 0.5 inches (68 percent) such that it is now below the arresting gear cable centerline to better enable scooping performance," the report states. "The proposed hold-down damper redesign will consist of modifications to the AHS actuator damper such that a lesser number of orifices will temper tailhook bounce dynamics."
The program will conduct a probability-of-engagement analysis of the redesigned components sometime this month, and following a successful design review, "the plan is to manufacture the redesigned components and then conduct rolling engagements" at Lakehurst, the report adds.
However, the report notes that a redesign of just the tailhook may not be possible, and, in a worst-case scenario, a major structural redesign of the aircraft would be necessary.
"With corrective action still in development, the AHS is considered an area of major consequence," the report notes. "If the proposed redesigned components do not prove to be compatible with MK-7 arresting gear, then significant redesign impacts will ensue. Accordingly, the program is conducting a formal trade study to assess options beyond AHS redesign."
The report states that one of the options is to adjust the location of the AHS on the airframe, but "since arrestment loads are significant and the aircraft has certain constraints with respect to engine location and survivability considerations, any readjustment of AHS location will have major, direct primary and secondary structure impacts."
Program officials don't have complete information on the problem and won't know just how significant the AHS issue is for some time because the April rolling engagements are just the initial stages or arrestment testing before carrier suitability demonstrations, according to the report.
"This issue represents a major concurrency risk which would have a significant retrofit impact to [low-rate initial production] aircraft already delivered, a large re-adjustment to the current F-35C production process build-up flow and, in many respects, invalidate previously obtained developmental test and evaluation data," the report states. -- Dan Taylor
_____________________________
Winslow T. Wheeler
Director
Straus Military Reform Project
Center for Defense Information
301 791-2397 (home office)
301 221-3897 (cell)
Winslow T. Wheeler
Director
Straus Military Reform Project
Center for Defense Information
301 791-2397 (home office)
301 221-3897 (cell)
No comments:
Post a Comment