Forgive me for my ignorance, but I understand that the only bolts which have been checked are those which secure door plugs. The checks have found that in many cases they are not tightened to spec.
I imagine there are hundreds of thousands if not millions of bolts on an airliner. How is it that the industry has confidence in the rest of them, and that the investigations are limited to the plug door bolts?
A convincing explanation I saw is that usually all doors are loosely attached by the subcontractor, since Boeing needs to remove them to build the interior. Then puts them back to specs.
A miscommunication probably happened where the plug doors were not tightened to specs same as every other doors, but Boeing didn't touch them (or checked) for their usual interior setup.
The whistleblower said they don't usually do that but had to open this door (not remove it) and merely opening the door doesnt require someone to signoff on the bolts being put back in place
You may have seen my comment. I was quoting my neighbor's speculation, who was career QA/QC at Boeing.
Since then, we have the whistleblower's account.
TLDR: A bureaucratic snafu where the record keeping didn't match the actual work. The repair of the plug's air seal was miscategorized ("reopen" vs "removal") in the system, so did not trigger the required post-repair inspection, which would have (most likely) spotted the missing nuts.
My neighbor said he'll look into the whistleblower's account, though he admitted it was plausible.
Also:
IIRC, castle nuts, which use cotter pins, are used for the plug's bolts. Meaning no tightening or torquing. The pressure differential keeps the plugs sealed. The bolts just keep the plug in place.
You probably know more about these details than me, I was referencing Real Engineering's video [0] on the subject.
If the whistleblower's information is true, then it's an even bigger fuckup than expected. But I'm worried it could lead to the management throwing a random worker under the bus to cover their dangerous practices.
For one, the door plugs are installed not by Boeing but by Spirit Aerosystems. Alaska’s maintenance will be focused on that specific vendor’s performance.
Secondly, other bolts will be checked far more frequently as part of standard maintenance. Door plug fitments typically are only checked during heavy checks (which occur every few years depending on type and interval) unless there’s a specific incident that demands an immediate assessment.
I imagine there are hundreds of thousands if not millions of bolts on an airliner. How is it that the industry has confidence in the rest of them, and that the investigations are limited to the plug door bolts?