I dont think this issues will be a problem in the long run though. F35 project is to big to fail.
This is relatively minor issue all in all...and related to MRO (fairly downstream issue). These issues become more steady-state and reliable/baked-in (intrinsic numbers wise) only with a decade or more (from my experience in the industry on commercial side).
It pops up in newsfeed because of the scale of the program (and F-35 interest w.r.t military matters)...given inertia from the earlier (somewhat more serious) problems reported in news media many years ago.
Similar has happened in all previous engines with such scale (say F-16 i.e F-100...esp during 80s).
In fact I can go into some length at what the problems (and workarounds) were and are with F-100 at start, mid and current era.
There is famous legacy workaround with the afterburner for example...which came with lot of precise effort...so it works within confidence level needed (at some nth principle depending who you ask) so why fix it (at first principle at greater cost) etc.
The stall issues for the engine itself were notable (and their eventual fixes and workarounds)...there is a large body of papers concerning this I can refer anyone to if interested.
The MRO issues were also considerable during this time period, leading to USAF telling gen dynamics to change engine bay of F-16 to accept a GE engine to better hedge this. i.e It was such an issue that it trumped the earlier philosophy of (shared engine with F-15) economy of scale.
But would one project, at the time, the F-16 (in the 80s) to be a failure (or going to be one) given this? Would one do so in hindsight?
The (larger + upstream) issues can, have and will pop up in the sector in any engine (during development and early production/deployment given each engine has different characteristics from its geometry and materials available/incorporated, its not simple case of learning from one and you are good to go forever after it on the issue/principle at hand).
So smaller issues are even more inevitable when talking about the downstream (say 70%+ bulk done/proven) issues w.r.t MRO projected versus actually realised....especially with ambition/revolution level versus a more steady iteration churn.
i.e Overall it is not too surprising and even somewhat inevitable given what is being attempted at this thrust class (w.r.t size/role, performance, reliability and MRO logistics), that too with several extra notable features/innovations found nowhere else.
The larger+upstream development related problems were all fixed (engine screech etc), i.e the ones that got like 100 times more press-coverage drama than this one (after all given program costs, size and it being fundamental upstream issue etc)....but there is no inherent structural problem/flaw with engine now.
Current MRO issues simply is matter of producing+adding more engines+parts stockpiled + more maintenance team work-hours (i.e a cost increase to assure same level of capability) till the fixes are found and implemented.
Data and lessons from these issues will feed in to next iteration of engine development for both this platform, concurrent platforms and the next era of platforms.
BTW, Even 70% platform ready rate (at this scale + tech level especially) is something a Russian engine (arguably the only perceived peer competitor out there that is outside of the NATO+allies ecosystem) would literally kill for.
Russia took a big kick to its groin in this area (relative to its efforts+success in field during USSR era) during the 90s and 2000s (given the time+funds unable to spend here like they otherwise would have if say USSR didnt collapse and instead improved economy at some rate.
Compare the opportunity costs of that hypothetical w.r.t to the reality of Russia idling/atrophying and even carving out and cannibalising significant proportions of its sector here like ended up happening for nearly 2 decades.
Stuff gums up big time when you do not use it at scale needed to keep crucial things warm (like how you incorporate every day lessons from the process flow) compared to nominal idling or worse (skeletal+frozen).
The old adage of things getting rusty etc applies a lot in production+realised engineering feedback to RnD side. This is massive conversation to have just by itself.
Thus they (Russia) have (in my estimation based on others vastly more in the know than I am) maybe 10 - 20% of the assured+achieved RnD in mid and last tier production QC (compared to the west) due to these "lost" years (and being behind to begin with before it)...and most of it is from catch up in the recent decade.
This takes big toll on readiness rate and MRO.
I can say this range because I know the numbers in more minute level between PW-GE-RR in various sectors of the engine tech itself...we are almost always comparing with each other (this working knowledge), especially if you sample clients and the appropriate MRO guys working on and well experienced on competitor platforms.
The 3rd appearing (China) is very new entrant and would be some % ratio of Russia on these factors...as they are quite behind Russia in a number of the first and 2nd principles stuff still (though they have made lot of progress on it is my understanding).
The crucial thing China has compared to Russia is the vast bulk to fund more breakouts (especially sustainably) and also develop and incorporate knowledge from production at scale.
But nothing can really be projected or guaranteed when they will surpass Russia overall in this field...since things are held close to chest and are very opaque for time being (especially compared to whats "out there" and proven-deployed from NATO and Russia).
Both (Russia and China) thus need to have far more aircraft (and personnel engaged that then cant be engaged elsewhere) than they otherwise would (this takes costs too) per realised deployment + deterrence + power level.
Just to put some stuff into context for folks here....to think more in the larger paradigms involved...past more cursory media stuff.
At some point hopefully I cover more in my jet engine series, time has been scarce for it lately compared to what I originally thought and hoped. There's my own smaller case of realisation of earlier projection in play heh.
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