Posted on 02/13/2020 7:01:34 AM PST by Enlightened1
This is reassuring:
“Inspections of some aircraft—Lockheed did not specify how many, or who had conducted the inspections—“indicated high levels of compliant fastener installations,””
I guess if you are not flying one of the ones with the inferior fasteners. In my non mechanical engineering mind, I would have to believe that fasteners are things that hold things together and that requiring sufficient strength and weight bolts for this critical job could be of some importance. Then again, I am not a government contractor either, especially one who may have to do an expensive inspection and replacement of inferior parts.
So if the lower cost and lower strength Titanium fasteners are sufficient, why were the more expensive fasteners spec’d in the first place? There had to be a reason, a margin, a service life, something. Those early F-35s do not have that. Will LM face a penalty, contract action, loss of fees?
If they’re worried about paint/coating on them maybe simply put each type of fastener in separate colored bins? Make it easy for the assembler to distinguish which was which? Maybe do a quick count (or weigh-in) at the end of each shift as a QA check that the right fasteners are being used at the expected rates...
I doubt that would make much difference to Bubba. I worked instruments in the Air Force. Right on the door for the compass transmitter was spray painted, "Use only non-ferrous fasteners". When a pilot would complain that the compass system was screwy, the first thing we'd check were those screws for the compass transmitter and many, many times the problem was because Bubba used the wrong screw(s).
I looked up how they work and I figure they would be extremely difficult to remove.
Oops.
L
This kind of “a mistake was made, but it doesn’t matter” should scream cover-up and who is getting paid off to allow the planes to fly uncorrected. If I were a pilot, I would be screaming bloody urder to have this fixed before I would fly this model of aircraft again.
So I need to take my F-35 back to the dealer? It better be covered under the warranty.
At $122,000,000.00 each I would expect better quality control.
Yes they are. And often in areas that once the assembly is complete very hard to access.
I read the article.
You missed the point.
LM is now trying to cover for their mistake by acting like either bolt is good enough. If true, they should have designed with the lighter, less expensive option. The spokesman’s comment makes no sense.
Been there....USAF 81-09.
I have said before that lockheed should be stricken from the list of qualified military contractors.
If the strength of inconel was not necessary at four times the cost of the alternative it would not have been specified. I have seen engineering specifications “reasoned” away because the repair is too expensive or too hard. It never goes well.
The designs were done in a time of deliberate and rational thought and supposedly rightfully subjected to focused criticism. Reversing this under pressure is almost always wrong.
Whatever competence lockheed had and may still have has been buried by unethical management. James Comey ring any bells?
Compromise is for politics and not for engineering. This will get out of hand and people will get killed but more importantly our war fighting ability with this bastard of an airplane that we have put all our eggs into is also compromised.
Just another excuse for failure.
Hilarious
There’s a reason that procedures are written
Occasionally some of the geniuses on the line could stop joking around and read the damn procedure, identify the part (it’s not hard, they’re marked) and use it. And where was the Quality guy checking their work? They’re supposed to look for exactly this.
Just sloppy, and usually dismissed with “oh don’t worry, those bolts are good enough”.
The fact that the Margin of Safety is > 1 (FS=2) in this case is irrelevant, that’s what the design calls for and the performance of the parts around it depends on those margins for both current operation and long term reliability as they are subjected to cyclic stress, corrosion and thermal cycling.
In a just world LM would be bankrupt.
As I’ve read regarding the building of the SR-71, which used titanium extensively, they had to mandate that NO chromium or cadmium plated tools could be used. Evidently even incidental contact would render the titanium brittle. They therefore had to create all titanium tools.
Are titanium ONLY tools mandated fro the 35? It would seem to me that if you’re going to titanium bolts in critical areas you don’t want anything that could render the metal brittle. And apparently these bolts are indistinguishable from any other bolt where the use of plated tools is not so critical.
Then again, I suppose the metallurgy has improved to the point where it is no longer an issue.
Post hoc value engineering.
At first I thought, as far as the costs go, $5 vs $20, no big deal.
Except there are supposed to be about THREE THOUSAND SIX HUNDRED Inconel ($20) bolts PER AIRPLANE!
We don’t know how many times per plane that the wrong bolts were used. 1% or 100% of the time. A lot more of them per plane on carrier aircraft.
How often has there been any failures of either type of bolt? Ever? Common?
This problem requires a LOT more study or the release of studies already undertaken.
These are not the bolts you are looking for.
Happens more often than you’d think. Lockheed will undoubtedly pay to have the fasteners replaced (not an easy task - holes probably get oversized).
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