Boeing ... WTF ?

[rb1957]

From Flight today ...

USAF pauses KC-46 deliveries over structural cracks
3 Mar 2025

The US Air Force, which operates 89 of the 767-derived tankers, has paused delivery of new aircraft after the discovery of structural cracks in two recently assembled jets that Boeing was preparing to turn over.

They found cracks in the planes in the factory ?? "paused delivery" ... why not "grounded" ??

 

[SWComposites]

rb - my first guess is someone left the shims out of a joint and the installed fasteners pulled the gap closed causing cracks.

 

[3DDave]

Had production do that on expensive composite items. Shimming was a last step on a 3 point mount and someone thought that it was necessary to crank the fasteners down full torque before getting there. It jacked out potted in place threaded bosses. The alignment shims were right there in the plastic baggies awaiting the final precision alignment step. It would not have been so bad if they'd heard the crunchy sound of the potting getting broken and stopped with the first one, but they did a bunch of them.

As a side issue, not sure about other places, but from the design side I got annoyed by production holding up drawing sign-off for expensive items because they wanted to save 25 cents on a <100 qty part but then refused to require manufacturing engineering to pass their process back to engineering for approval before they did hundreds of dollars in damage or created thousands of dollars in scrap.

 

[SWComposites]

Yeah, that problem exists lots of other places. And Ops whines about Eng not accepting the damaged parts.

 

[IRstuff]

Production once burned through four $250k laser units because the power supply "gold" unit failed and they kept trying new lasers on the bad power supply until it dawned on them that maybe it wasn't the new lasers' problem, but too late. Cost almost as much as original price to R&R the damaged units.

 

[rb1957]

ok, sure ... but that'd be a "simple" liaison problem (RNC/NCR/MRB/etc) to fix ... it'd be found pretty much when done ... why "pause production" ?
unless they're hiding stuff and that'll never turn out well.

 

[3DDave]

If I were "hiding" some massive top secret production problem the last thing I would do was pause production. I would absolutely carry on (No, no I actually would not) as if there was no problem at all.

A pause in production is what one does to expose production problems. It freezes components in place, it stops people from messing with covering problems up. It helps follow back through the process to see where some error has been made and gives time for inspectors and others to review parts and processes in more detail without the distraction of keeping the line moving.
---
We stumbled on a case where a close look at the parts list showed that quarter inch screws were retaining footman loops with dia. 0.190 holes. Someone didn't read the specification sheet closely. It should have been caught on the prototype build.

Engineering called manufacturing asking if there were problems with this and they said "Nope. They all fit."

They all fit because someone couldn't install the first one, and went and got the whole box of them, took then to a drill press, and drilled them all out to the larger size. Thanks. Very f'n helpful. I wasn't part of dealing with the fallout - I imagine we had to create an altered item drawing to drill out a MIL-STD part for no good reason. The good news is the workers there were paid peanuts so it's not like it added a great deal to the cost.

Same assembly line was found using angle grinders at final assembly because manufacturing management decided that weld fixtures for complex parts were too expensive and, instead of inspecting and rejecting the distorted parts, they would have assemblers hammer what they could and grind what the hammer couldn't handle.

 

[rb1957]

yeah ... Operations "correcting" drawings ! happens all the time, then we get back to the drawing and think "how have we been making this for the past X years ?" ... oh, dear ...

 

[WKTaylor]

Hmmm... I wonder exactly/roughly-what parts appear to be affected?

PS: Sometimes, when production is interrupted by natural disasters, parts problems, holidays, strikes, etc... re-start is a painful process.

One particularly memorable event for me was a tornado-outbreak that forced evacuation of a chem-stripping facility, mid-week. The shop guys came back on Monday only to find several parts in different stripper bath solutions had been 'forgotten' and were left in the baths for 5+days... every part was a total loss due to violating chem soak times.