Hundreds of F-35s have wrong fasteners

It was announced today that most of the F-35 fleet has the wrong fasteners installed in "critical locations". The aircraft are supposed to have Inconel fasteners installed, but instead have titanium fasteners. The Inconel fastened are used to resist corrosion, and the titanium are used to save weight. Lockheed says that nothing will need to be done, but the JPO will make the final decision and issue any directive.

www.airforcemag.com...

a reply to: Zaphod58

Imagine buying a Lamborghini and they tell you they used the wrong lug nuts...

Sounds like the company in charge of this mistake should eat the cost of replacing the fasteners with what the tax payers paid for.

Oops. Sounds like that could be a costly undertaking. I'm a little surprised that they're considering leaving them as is. I would think they would at least tear one down and double check the Titanium bolt strength. Lockheed is saying they're made double the strength of acceptable grade.

Ti bolts $5 Inconel $20 surely they weren't shaving cost? Which would be peanuts with their budget.

a reply to: mtnshredder

They may choose to leave them in place until each affect goes through PDM. They'll be torn down then and it will be a lot easier to do then.

originally posted by: Zaphod58
a reply to: mtnshredder

They may choose to leave them in place until each affect goes through PDM. They'll be torn down then and it will be a lot easier to do then.

That would make sense barring a higher than normal premature fastener failure. Do you know the hr intervals for PDM?

Just inspect them for corrosion.

Which is stronger?

Does Titanium have a corrosion problem?

a reply to: mtnshredder

Right now they're using a modification schedule, similar to the F-16, so they're looking at between 2 and about 6 years between visits.

a reply to: visitedbythem

Titanium is a strange metal. It's strong and light, but will corrode from the strangest things, such as grease pencils. So it'll depend on where they are, and what they're exposed to.

Thats a pretty big mistake even if the impact isnt.

The first few EFA Typhoon had carbon fiber laid incorrectly on their tail but IIRC it was between 3 and 6 and was caught before they flew.

Do you know if these were all fitted on the components the UK manufacture or across all sub assemblies?

Is it limited to a variant?

Could be just as simple as the faster supplier filling up the bins with the wrong fasteners on the assembly I suppose but I would have hoped there were QA checks on the bins occasionally.

Has this happened on commercial aircraft ever?

originally posted by: Bluntone22
a reply to: Zaphod58

Imagine buying a Lamborghini and they tell you they used the wrong lug nuts...

You know, Lamborghini uses Ti lug bolts, right???

a reply to: Forensick

Yes. Both wrong fasteners and incorrectly installed fasteners.

originally posted by: FlyingFox

originally posted by: Bluntone22
a reply to: Zaphod58

Imagine buying a Lamborghini and they tell you they used the wrong lug nuts...

You know, Lamborghini uses Ti lug bolts, right???

Nope.
Not really the point.

originally posted by: Bluntone22

originally posted by: FlyingFox

originally posted by: Bluntone22
a reply to: Zaphod58

Imagine buying a Lamborghini and they tell you they used the wrong lug nuts...

You know, Lamborghini uses Ti lug bolts, right???

Nope.
Not really the point.

Actually Lamborghini don't have lug nuts, they have straight bolts, you need to have a couple of guide bolts so when removing a wheel it doesn't fall when you remove them bolts...

The shear strength of Titanium is about 79,800 psi and Inconel is about 69,600 psi. So it should be OK in that area. Titanium has a nasty habit of work hardening due to vibration. That can make it brittle, which could be an issue.

a reply to: JIMC5499

The biggest concern is going to be corrosion, especially on the C, which has over twice as many inconel fasteners as the other two versions.

a reply to: Zaphod58

Yep. That sea air will do it all of the time. 28 day is going to suck on that thing.

I’m fairly sure inconel is stronger than the same weight of titanium alloy and much more heat resistant. But after reading the post about their relative shear strengths I’m not sure I know what I’m talking about.

I guess it's naive of me to wonder how such a simple mistake makes it this far into the process.

Didn't they put lights on the damn thing that don't comply with FAA regulations at one point?

Titanium work hardens and also gets harder with heat but yes Inconel is better for Corrosion resistance..Grease pencils and carbon pencils are a big nono with Ti...
If they are HiLoks its going to take some time to replace them..Cherry Maxes,well Id have a good mental support crew for the workers Taper Loks no dont even ask...