DOT&E Problems with F-35B and Risks of Excessive Concurr

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spazsinbad

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Unread post13 Jan 2012, 23:31

via initial 'maus92' headsup here: http://www.f-16.net/f-16_forum_viewtopic-t-16715.html

Joint Strike Fighter Test Report Shows Heightened Problems with F-35B and Risks of Excessive Concurrency Jan 13, 2012

http://pogoblog.typepad.com/pogo/2012/0 ... ncurr.html
Youse can read the bumpf on the above webpage. I have excerpted text that interest me (the graphic is in another thread: http://www.f-16.net/attachments/f_35fli ... 11_107.gif). So youse may imagine that other things in the report will interest youse. So go read it....

Read the section of the DOT&E's report on the JSF here: http://www.pogo.org/resources/national- ... eport.html
OR
PDF here: http://s3.documentcloud.org/documents/2 ... r-from.pdf (0.23Mb)
_____________________________________

DOTE Report Jan 2012 F-35 Section:

http://s3.documentcloud.org/documents/2 ... r-from.pdf (0.23Mb)

"Air System-Ship Integration and Ship Suitability Testing
• F-35B.
The program accomplished the first of two STOVL developmental test ship trials on the USS Wasp in October with test aircraft BF-2 and BF-4. The testing focused on developing initial short take-offs and vertical landings in the initial flight envelopes for deck operations, performing initial ship compatibility assessments, and collecting environmental data from instrumented ship locations. Seventy-two short take-offs and vertical landings were completed during the 19-day deployment in conditions of up to 33 knots of wind-over-deck and 10 knots of starboard crosswind. Some standard deck operations and maintenance activities were demonstrated, including fueling and defueling, aircraft tiedown, jacking, tire replacement, augmenter boost pump and door actuator replacements, and hydraulic servicing. Environmental data were collected to assess thermal stress to landing sites and shielded areas, and acoustic effects to ship personnel. Current plans place the second set of trials in August 2013.

• F-35C. The program began F-35C carrier landings, catapult take-offs, and jet blast deflector testing at the Lakehurst, New Jersey, test facility in July."
________________________

F-35B Flight Sciences
• The test team was able to improve the tempo of STOVL-mode flight test early in the year in order to open sufficient flight envelope and accomplish other shore-based build-up for the ship trials in October 2011. Test and engineering teams accomplished a significant amount of modifications to the test aircraft to bring about this needed increase in the pace of STOVL-mode flight test. To accomplish 2011 goals, the test team also worked to overcome the challenges of low aircraft reliability and parts shortages.

• The test team was able to conduct safe flight tests of the STOVL-mode and successfully completed initial ship trials using flight monitoring systems in SDD test aircraft. The program has not completed the final re-designs and plans to correct deficiencies through modifications of F-35B production aircraft intended for the fleet, which cannot be monitored in-flight because these aircraft are not instrumented. Production aircraft will be restricted from STOVL-mode flight operations until Service airworthiness authorities grant a flight clearance. A significant amount of flight test and development of system maturity of the final STOVL-mode door and propulsion system designs remains to be accomplished. A system mature enough for unmonitored STOVL-mode flight may be needed as early as late 2012 to coincide with the delivery of lot 4 F-35B aircraft to the Marine Corps at Yuma, Arizona. If testing of the changes is not complete and needed modifications are not installed by late 2012, aircraft at Yuma will fly in CTOL-mode only....
_____________

.....• The vertical lift bring-back requirement is a primary STOVL-mode attribute and is a Key Performance Parameter (KPP). It is the weight of a minimum fuel quantity and other necessary payload needed to safely recover the aircraft on the ship after an operational mission, plus a representative weapons payload. Managing aircraft empty weight growth is essential to being able to meet the vertical lift bring-back requirement. The F-35B aircraft weight management challenge is complicated by balancing available lift, thrust required, and vertical descent rates in the vertical landing mode. 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. This weight margin represents 0.71 percent of the current weight and allows for only 0.22 percent weight growth per year until the technical performance measurement assessment deadline, which is prior to the end of SDD. The program recently determined that allowing a greater descent rate to touchdown (7 feet per second) plus possible positive thrust margins available from the lift fan may add an additional 142 pounds of weight tolerance to the technical performance measure not-to-exceed weight. This additional weight increases the margin to 1.2 percent of current weight and allows for 0.36 percent weight growth per year. Managing weight growth with such tight margins for the balance of SDD will be a significant challenge, especially with over 70 percent of the scheduled F-35B flight sciences test flights remaining to be accomplished in the next 60 months. For comparison, weight growth on the F/A-18 E/F was approximately 0.69 percent per year for first the 42 months following first flight.

F-35C Flight Sciences
.• As F-35C flight sciences focused on preparation for and execution of carrier launch and landing testing at Lakehurst, a limited amount of other envelope expansion occurred in 2011. The F-35C flight sciences test points accomplished thus far are approximately 15 percent of the total expected in SDD.

.• The lack of available flight envelope in the transonic regime currently constrains testing of F-35C aircraft handling qualities. In limited testing using flight control software that benefitted from F-35A and F-35B testing, the F-35C aircraft performance in the transonic flight regime demonstrated the predicted intensity of uncommanded rolls but higher buffet levels. The F-35C aircraft was expected to have the greatest challenge of the three variants in the transonic flight regime, which led to the decision to incorporate structural provisions for the installation of external spoilers in one test aircraft.

.• The carrier launch and landing testing at Lakehurst provided valuable lessons regarding the impacts of these dynamic environments on the aircraft early in the testing. Corrections and regression testing are needed as a result of the discoveries listed below. The program is also working to correct other performance problems such as excessive nose gear oscillations during taxi, excessive landing gear retraction times, and overheating of the electro-hydrostatic actuator systems that power the flight controls. The program will subsequently evaluate the need for modifications of production aircraft for these items.

Discoveries included:
- Flight test aircraft could not engage the arrestment cable during tests at the Lakehurst, New Jersey, test facility. 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.

- Hold-back bar and torque arm components, which keep the F-35C aircraft from moving forward when tensioned on the catapult at full power, require a redesign due to the use of incorrect design load factors. Actual loads are greater than predicted. The impact of these greater-than-predicted loads on strength and fatigue characteristics is under analysis by the program.

- Loss of inertial navigation and GPS inputs to pilot displays occurred during a catapult launch. Root cause analysis was in progress at the time of this report.

- The test team conducted initial testing in the transonic flight regimes with one version of air vehicle software on aircraft CF-2. Problems similar to the other variants were observed, such as excessive buffeting and roll-off, at times making the helmet-mounted displays unreadable.

- Higher than predicted temperatures exist in the electro-hydrostatic actuator system during flight testing of the aircraft in a landing configuration. This component provides the force to move control surfaces.
_______________

Mission Systems
• Discoveries included:
- The helmet-mounted display system is deficient. It is meant to display key aircraft handling/performance information as well as tactical situational awareness and weapons employment information on the pilot’s helmet visor, replacing conventional heads-up display systems.

-- Deficiencies include integration of the night vision capability, integration of Distributed Aperture System video for night vision, symbology jitter or swimming, and latency. These stem in turn from poor acuity with night vision camera hardware, limited 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.

-- The program began pursuing a dual path to resolve the technical shortfalls and provide a system that will enable flight test to proceed and meet operational mission needs. One path is to complete development of the original helmet-mounted display system by the end of SDD Block 3. The alternate path is to integrate a technically mature, existing helmet-mounted display system that addresses the symbology stability problems that have been discovered, but requires an additional night vision system (such as existing night vision goggles) to provide night combat capability, and does not display Distributed Aperture System imagery on the pilot’s visor. The impacts of these two paths on mission systems schedule cannot be measured until plans are integrated into the master schedule.

-- The program made several modifications to the helmet to be useful in daytime flight test and the benign initial training environment. Shimming and visor alignment changes have corrected some of the virtual heads-up display deficiencies for flight test and initial training; however, more work is needed for the existing helmet to support certain flight test missions in the near future (e.g. high angle-of-attack, elevated g-loading, weapons employment) and combat operations.

- Panoramic cockpit displays in the mission systems aircraft overheat during flight test. The program is pursuing modifications to test aircraft to increase cooling and decrease heat load so that testing can continue.

- While mission systems software has been stable during flight tests so far, startup time and startup stability is poor, usually taking more than 30 minutes to complete. The most recent Block 1B software improved startup times, but more improvement is needed for suitable operations.

- Radar anomalies in flight included loss of air target tracks without indicating radar faults or failure to the pilot. Root cause analysis was in progress at the time of this report.
__________________

Air System-Ship Integration and Ship Suitability Testing
• The F-35B initial ship trials on USS Wasp supported initial short take-off and vertical landing envelope expansion efforts for shipboard operations with data collected as planned across a portion of the wind-over-deck conditions. As expected, high starboard crosswinds produced the most challenging environment. One approach to hover prior to a vertical landing was waved off by the pilot due to turbulence in the ship’s airwake. A minimal nozzle clearance of 2 inches was observed at rotation during a short take-off with high starboard crosswinds when the pilot made an aggressive correction to maintain centerline. The test team demonstrated deck and hangar operations.

Although maintenance was completed while aboard the ship, limited support equipment was positioned on USS Wasp and no ALIS equipment supported the deployment aboard the ship. The test team created a virtual private network connection between the ship and the prime contractor in Fort Worth such that they were able to process maintenance actions as if operating at Patuxent River. Aircraft BF-2 diverted to Patuxent River twice during the deployment for maintenance – once for a fuel leak that could not be addressed at sea and once when the team elected to have upper lift fan door actuators replaced ashore. The upper lift fan door actuators on BF-4 had to be replaced twice during the trial period, once at Patuxent River and once at sea with an embarked maintenance team.

http://www.f-16.net/attachments/f_35fli ... 11_107.gif

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Last edited by spazsinbad on 14 Jan 2012, 02:18, edited 1 time in total.
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Unread post13 Jan 2012, 23:47

So, where are the 'heightened problems' with F-35B?
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popcorn

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Unread post13 Jan 2012, 23:49

- Flight test aircraft could not engage the arrestment cable during tests at the Lakehurst, New Jersey, test facility. 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.

Could the fix be this simple? Hopefully so.
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Unread post14 Jan 2012, 01:03

Spaz, this is part of a larger annual end-of-the-year report from DOT&E. We are a very short time in front of the budget release here in the US and there are many who leak for the purpose of shaping opinion for political purpose (including both service and commercial interests). Do you have the rest of the report rather than just a pogo pdf of the F-35 section?
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Unread post14 Jan 2012, 01:29

quicksilver, AFAIK previous DOTE reports are divided into sections to concentrate on one piece of hardware. The F-35 bit would be important for the F-35 and no I don't have anymore. The entire report will be released soon enough I guess - it is anticipated. I'm not a serial leaker but may develop that problem in me old age. :D

You initially asked about the 'heightened F-35B issues'? These are in the report. My excerpts do not include all the material in the PDF report available for download or it can be read online at the URLs above.
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hcobb

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Unread post14 Jan 2012, 07:04

http://defense.aol.com/2012/01/13/f-35b ... sters-say/
testers found "the fuel tank inserting system is incapable of providing protection from threat-induced fuel tank explosions during some critical segments of combat missions when the aircraft is most likely to be hit."

Let's name the aircraft after something that has a bright flash and a loud boom. Any suggestions? :D
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Unread post14 Jan 2012, 13:31

spazsinbad wrote:quicksilver, AFAIK previous DOTE reports are divided into sections to concentrate on one piece of hardware. The F-35 bit would be important for the F-35 and no I don't have anymore. The entire report will be released soon enough I guess - it is anticipated. I'm not a serial leaker but may develop that problem in me old age. :D

You initially asked about the 'heightened F-35B issues'? These are in the report. My excerpts do not include all the material in the PDF report available for download or it can be read online at the URLs above.


There are no 'heightened F-35B issues' in the report -- none. DOT&E releases an Annual Report that covers a wide range of platforms (including some now in operational service). Some of the 'serial leakers' in the Pentagon have chosen to pdf just a part of it for political purpose, knowing full-well that the public doesn't understand developmental flight test (nor the difference between it and OT) and few have any reference for what is normal and what is not. Thus, a recounting of the previous year of developmental testing (with data that conveniently ends in November) looks like more 'bad news' on F-35. It is not -- it is simply a recounting of what happened, distributed virally and sensationalized by demagogues all over the blogosphere (not you Spaz) for political purpose. Folks shouldn't be naive.

There is nothing new in any of it -- nothing. And, the use of data that ends in November intentionally obscures a terrific year of flight test progress. Each F-35 variant exceeded test plan goals for flights and test point completion for the year. And to those who would ask why they were 'behind' in test point completion in November -- everyone who works in DT knows that credit for test point completion lags completion of the point in flight because some test points require more analysis than others.

And in other news, the Marines first two jets arrived at Eglin, 'Code 1' 8)
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Unread post14 Jan 2012, 19:28

Excessive concurrency is the name of the whole program!!!! :lol:
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Unread post15 Jan 2012, 20:30

Further to 'quicksilver' spot on response there is this LM response to news reports from here:

F-35 Showed ‘Mixed Results’ in Tests, Pentagon Report Says Jan13, 2012 By Tony Capaccio
--Editors: Steven Komarow, Jodi Schneider

http://www.businessweek.com/news/2012-0 ... -says.html

"...Lockheed’s Response
“The report recognizes the numerous accomplishments of the F-35 program in 2011 such as the outstanding results from F-35 ship trials, completion of F-35C structural testing and the fact flight sciences and flight testing either matched or exceeded plan in 2011,” Lockheed spokesman Michael Rein said today in an e-mailed statement.

Flight tests in the report covered only the period through November, he said. Through December, “the flight test team completed 7,823 test points, an increase of 1,744 test points over the number published.”

The F-35 flight-test plan for last year called for the accomplishing 6,622 test points, Rein said....

...Rein said “the individual technical issues cited in the report are known issues that have engineering solutions either identified, in work or are currently in flight test.”

The assessment follows a team of Pentagon test, systems engineering and structural experts who concluded in a Nov. 29 report that “no fundamental design risks” would preclude production of the jet for the Air Force, Navy and Marine Corps.

It identified 13 current or likely test issues of varying severity, the combined effect of which “results in a lack of confidence” in the aircraft’s “design stability.” The issues include the Navy version’s tailhook for aircraft carrier landings, the system for dumping extra fuel before landing and excessive aircraft shaking during flight."
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