Thread by @TrentTelenko

I see this F-35 procurement problems post is getting traction thanks to @elonmusk .

Let's add the F-35 problem list with bolts AKA fasteners.

1/
F-35 Fastener Corruption🧵

I cannot begin to tell you all how fishy this passage from that article is:

"In addition to the F-35 production line at Ft. Worth, Texas, the commingling of the two types of bolts was also discovered at the Italian F-35

2/

... Final Assembly and Check-Out (FACO) facility, but not the one in Japan, the DCMA reported."

Spot checking of aircraft production and depot level maintenance facilities fastener bins is a standard operating procedure for DCMA everywhere it has quality personnel.

3/

Finding incorrect bolts in a fastener bin at the then E-Systems Greenville Texas aircraft depot level repair facility was one of my first written corrective action requests in 1991.

4/

Which makes this passage is such utter horses---t. I don't know where to begin:

"Both fasteners are called “eddie bolts” and are similar in appearance except for a number stamped on them. The titanium bolts cost about $5 apiece, while the Inconel parts cost about $20 each. A Lockheed spokeswoman said the two parts are “very difficult to distinguish, visually.”"

5/

A simple perusal through these links will demonstrate how really different Inconel & Titanium bolts are. 

It isn't just a number on the end of the bolt.

6/
stindia.com/difference-bet…

This is a simplified visual of a bolt being installed in a metal structure.

7/
extreme-bolt.com/products-incon…

Inconel & Titanium bolts have different settings on the bolt huck guns that install them.  Inconel has higher tensile strength than Titanium. 

A huck gun set for a Titanium bolt WILL NOT install a high heat shear-resistant Inconel bolt.

8/

Again from the referenced 2020 article

"Inconel is an alloy of nickel and chromium, and is supposed to be used in places where greater strength and corrosion resistance are required, while the...

9/

...titanium bolts are used in areas where its strength and lightness helps reduce weight. Titanium, however, has a lower shear strength than Inconel."

Short form:

Inconel bolts are used in the F-35 engine compartment because of their high heat shear strength vs titanium.
10/

What that article carefully left out was titanium bolts were used inside the F-35 engine compartment in lieu of inconel.

The F-35 JPO did not do a fleet inspection to ferret out which F-35's were affected.

Inconel is magnetic. Titanium isn't. Using magnetic LED flashlights on bolt heads is easy
11/

Every production operation on an aircraft in foreign object-controlled (FOD) areas has an electronic worksheet listing tools, their settings, parts, where parts are installed, the order of installation, and sign off boxes for operations completed. 
12/

Materials and tools going into a FOD controlled area are accounted for whenever you enter and leave the area and at the end of the shift.

13/

These operations sheets are built around and feed the electronic "Build of Materials" that automatically purchases fasteners and all the other parts required for that operation on a plane.

14/

The chances of $5 Titanium bolts being 'accidentally' commingled and used in lieu of $20 Inconel bolts from start of F-35 production to Nov 2019, without detection by anyone, is so low as to be laughable.

15/

There were a whole lot of reasons that DCMA was ordered to put very large teams of inspectors inside the FT. Worth production line for the F-35 in 2020.

It certainly wasn't about trust.

16/

The 2022 DCMA stop of F-35 production acceptance happened because the discovery of Chinese rare earth metals in the F-35 engine structure.

This shows how utterly screwed F-35 pilots really are.


17/17

P.S.

"According to the DCMA, there are more than 48,000 fasteners of the two types on an F-35 fighter. The Air Force's F-35As have 848 Inconel bolts out of 48,919 total fasteners, or about 1.7 percent of the total. The Marine Corps' F-35B model has 877 Inconel fasteners out of 50,603, also 1.7 percent. The Navy's F-35C carrier-capable model, though, which has to endure the shock of repeated hard landings on an aircraft carrier, and is larger and heavier than the other two variants, has 51,353 fasteners, of which 1,813, or 3.5 percent, are made of Inconel."

airforcemag.com/lockheed-poten…

@threadreaderapp unroll please