The Hidden Troubles of the F-35 [DefenseNews]

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spazsinbad

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Unread post12 Jun 2019, 10:38

Holy Moly - too much to digest for this hoomanunit: https://www.defensenews.com/smr/hidden-troubles-f35/

Thanks goodness - a summary of the troubles here:
The Pentagon is battling the clock to fix serious, unreported F-35 problems
12 Jun 2019 Valerie Insinna

..."The 13 deficiencies include:

• The F-35’s logistics system currently has no way for foreign F-35 operators to keep their secret data from being sent to the United States.

• The spare parts inventory shown by the F-35’s logistics system does not always reflect reality, causing occasional mission cancellations.

• Cabin pressure spikes in the cockpit of the F-35 have been known to cause barotrauma, the word given to extreme ear and sinus pain.

• In very cold conditions — defined as at or near minus 30 degrees Fahrenheit — the F-35 will erroneously report that one of its batteries have failed, sometimes prompting missions to be aborted.

• Supersonic flight in excess of Mach 1.2 can cause structural damage and blistering to the stealth coating of the F-35B and F-35C.

• After doing certain maneuvers, F-35B and F-35C pilots are not always able to completely control the aircraft’s pitch, roll and yaw.

• If the F-35A and F-35B blows a tire upon landing, the impact could also take out both hydraulic lines and pose a loss-of-aircraft risk.

• A “green glow” sometimes appears on the helmet-mounted display, washing out the imagery in the helmet and making it difficult to land the F-35C on an aircraft carrier.

• On nights with little starlight, the night vision camera sometimes displays green striations that make it difficult for all variants to see the horizon or to land on ships.

• The sea search mode of the F-35’s radar only illuminates a small slice of the sea’s surface.

• When the F-35B vertically lands on very hot days, older engines may be unable to produce the required thrust to keep the jet airborne, resulting in a hard landing....

...The list of deficiencies as a whole is in some ways encouraging, the currently serving aviator said, because it looks like the issues are being identified by the engineers and technicians working on the program.

“I think what you see in that document is an airplane that fell behind schedule, that was rushed to get back up to schedule under immense political and industry pressure. They had a lot of next-gen[eration] technologies all at once, and they’re working through what all of that looks like together,” the aviator said.

“I don’t see anything in that document that makes me say: ‘Holy sh--, what did we buy?’ If the questions is, ‘Why does the aircraft have all these problems?’, I don’t know, it may sound trite, but it’s a really f--ing complicated machine.”"

Source: https://www.defensenews.com/air/2019/06 ... -problems/
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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quicksilver

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Unread post12 Jun 2019, 11:32

Hatchet job in front of the FRP/MY decision. Jet is probably doing too well in OT and the DOT&E weenies needed something to whine about, so they leak a Cat 1 DR list. Few in the public domain understand ‘deficiencies’ in a test context because they tend to understand jets like they understand cars; my wife in the kitchen — “...why would we buy something with ‘deficiencies’...?” DefNews editor needs some click hits so he or she tags the story with ‘previously unreported.’ Unreported to whom? The items made the DR list for bleeps sake.

Reminder: some DRs are never resolved. There are fighters flying around in service today after decades in service with still-unresolved DRs. I’m surprised some of the F-35 list are CAT 1s — eg the sea search mode. And, stealth coating stuff? Sounds like the tailplane heating when you spend lotsa time in max AB.

New aircraft always have stuff like this that you have to handle with for a while. Anyone who has flown new designs in the fleet early in the their design life knows this because they’ve lived it.

Cue POGO hysteria — 3, 2, 1...
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marsavian

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Unread post12 Jun 2019, 13:07

More detail on the more serious problems.

Supersonic speeds could cause big problems for the F-35′s stealth coating

https://www.defensenews.com/air/2019/06 ... h-coating/

Both deficiencies were first observed in late 2011 following flutter tests where the F-35B and F-35C both flew at speeds of Mach 1.3 and Mach 1.4. During a post-flight inspection in November 2011, it was discovered the F-35B sustained “bubbling [and] blistering” of the stealth coating on both the right and left sides of the horizontal tail and the tail boom.

During similar tests of the F-35C in December 2011, “thermal damage” that compromised the structural integrity of the inboard horizontal tail and tail boom were apparent.

Vice Adm. Mat Winter, who leads the F-35 program on behalf of the Pentagon, told Defense News that the department has taken steps to mitigate the problem with an improved spray-on coating, but added that the government will not completely fix it — instead accepting additional risk.

As justification for the decision, Winter noted that the issue was documented while the jet was flying at the very edge of its flight envelope. He also said the phenomenon only occurred once for both the B and C models, despite numerous attempts to replicate the conditions that caused the problem.

“We have put into place what we believe are the appropriate technical fix to ensure that our F-35Cs have the full envelope and capability to do the high-speed mission, if needed. That’s where we are. Right now, our United States Navy and Marine Corps flying the sea agree with that,” he said.

The new coating, which was introduced in Lot 8, allows the jet to withstand hotter temperatures caused by the afterburner, the documents stated. Winter characterized the material as able to withstand “what we call the thermal shock wave,” but declined to specify how the coating works or how much protection it provides.

“It may be some future advanced materials that can withstand the pressure and the temperature,” Winter said. “Then we see that, and we go, ‘Hey, look, we've got this on the book,’ [and] we do a test check to see if that new material solves that problem.”

The Defense Department has also instituted time limits on the number of seconds the F-35B and F-35C can fly at speeds in excess of Mach 1.2 while at full afterburner.

However, those restrictions are somewhat complicated, and it is unclear how pilots are expected to monitor their compliance to the limits while in flight.

For example, an F-35C can only fly at Mach 1.3 in afterburner for 50 cumulative seconds, meaning that a pilot cannot clock 50 seconds at that speed, slow down for a couple seconds and then speed back up. However, the time requirements reset after the pilot operates at military power — an engine power setting that allows for less speed and thrust than afterburner — for a duration of three minutes.

The F-35B can fly for 80 cumulative seconds at Mach 1.2 or 40 seconds at Mach 1.3 without risking damage.

But for both the C and B models, flying at Mach 1.3 over the specified time limits poses the risk of inducing structural damage to the aircraft’s horizontal stabilizer.

It is infeasible for the Navy or Marine Corps to operate the F-35 against a near-peer threat under such restrictions, the documents acknowledge.

“Pilot observed timers are not practical/observable in operationally relevant scenarios,” one document read. Another document said that “pilots will be unable to comply with time limit in many cases due to high mission workload, resulting in lost missions due to aircraft damage.”

And when those timer violations occur, they will result in “degradation of [stealth], damage to [communications, navigation and identification] antennas, and/or significant [horizontal tail damage],” one document explained.




F-35B/C have oscillation problems when above 20 degree AOA but software fixes coming ...

https://www.defensenews.com/smr/hidden- ... s-erratic/


So why didn't the F-35A suffer from either of these problems ?


More on the cabin pressure/blown tyre issues.

https://www.defensenews.com/air/2019/06 ... ting-pain/

https://www.defensenews.com/smr/hidden- ... -failures/
Last edited by marsavian on 12 Jun 2019, 13:15, edited 2 times in total.
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quicksilver

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Unread post12 Jun 2019, 13:12

It gets above those Mach numbers more easily.

In training, the reality about supersonic flight is you don’t spend much time above those numbers anyway because you don’t have the airspace (as in you will run out of the area or you have to turn around w a turn radius the size of New Jersey).
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mixelflick

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Unread post12 Jun 2019, 13:24

This was my favorite..

After doing certain maneuvers, F-35B and F-35C pilots are not always able to completely control the aircraft’s pitch, roll and yaw

Um... that's pretty important, don't you think? Flight control software? Or a structural issue??
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marsavian

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Unread post12 Jun 2019, 13:56

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quicksilver

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Unread post12 Jun 2019, 13:59

mixelflick wrote:This was my favorite..

After doing certain maneuvers, F-35B and F-35C pilots are not always able to completely control the aircraft’s pitch, roll and yaw

Um... that's pretty important, don't you think? Flight control software? Or a structural issue??


What exactly does ‘not completely control’ mean? In what context did this occur in flight test? That’s journalist language, not flight test language.
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quicksilver

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Unread post12 Jun 2019, 14:03

marsavian wrote:Software fixes coming.

https://www.defensenews.com/smr/hidden- ... s-erratic/


‘Modal confusion’

...that would get someone a new call sign if ever used in a fleet ready room. Something like, “MC” — modally confused.
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quicksilver

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Unread post12 Jun 2019, 14:31

Finally, somebody is talking about how ‘deficiencies’ are defined.

https://www.defensenews.com/smr/hidden- ... hortfalls/
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krieger22

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Unread post12 Jun 2019, 15:59

The authors are all claiming that this was done in the interest of "transparency", but yeah, it's a hatchet job whether they meant to or not.

Lots of material for the second coming of the basement dweller stupidity thread, but I don't want to monopolize submissions there now :wink:
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SpudmanWP

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Unread post12 Jun 2019, 16:18

The heat blistering the stealth coatings has only happened once on the F-35B/C and more importantly, they have not been able to replicate it even after trying multiple times.

The biggest issue I have with this hit-piece is that they keep throwing around "unreported" which is a demonstrable lie.
"The early bird gets the worm but the second mouse gets the cheese."
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marsavian

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Unread post12 Jun 2019, 16:25

The heat blistering on the stealth coating is not the most important issue especially as they changed the coating since, it is the damage to the F-35C tail structure and its antennas which implies a design fault. LMT has had 8 years to find the root issue, instead the solution is high Mach in both the F-35B and F-35C is time restricted which is a band-aid fix.
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Unread post12 Jun 2019, 17:59

marsavian wrote:The heat blistering on the stealth coating is not the most important issue especially as they changed the coating since, it is the damage to the F-35C tail structure and its antennas which implies a design fault. LMT has had 8 years to find the root issue, instead the solution is high Mach in both the F-35B and F-35C is time restricted which is a band-aid fix.


So, what is your solution?
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marsavian

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Unread post12 Jun 2019, 18:11

LMT have to eventually fix it, free of charge. The F-35 program will give them decades of profit, the buyers of the F-35C product, USN, are owed a product built to full product specification.
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zerion

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Unread post12 Jun 2019, 18:17

LMT response

Lockheed Martin Comments on Defense News Reporting
Lockheed Martin // June 12, 2019

Below, please find comments from Lockheed Martin on improvements underway addressing the items identified in Defense News’ June 12 article series.

Overall Comment

The F-35s today are meeting or exceeding performance specifications and delivering unprecedented capability and safety compared to legacy fighter aircraft. The feedback we receive from F-35 pilots is exceptional – and any pilot who has flown a legacy jet consistently relays back that if they are being sent in to harm’s way – they want the F-35, every time.

These issues are important to address, and each is well understood, already resolved or on a near term path to resolution. We’ve worked collaboratively with our customers and we are fully confident in the F-35’s performance and the solutions in place to address each of the items identified...

https://www.f35.com/news/detail/lockhee ... -reporting
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