In a properly functioning quality and safety management system, there's no awkward in-the-middle. The "open door plug" procedure is a planned part of the construction, inspection and maintenance of the airplane. And even if there was a doubt, the thing to do in that case is stop and document the doubt, and then document the process of discussion of the doubt, and then document the decision, including whatever change to the quality system may be needed to avoid this doubt arising the next time.

The problem here is not that Boeing does not know how to run both the original quality system and the system to modify it if necessary. The problem is the quality culture that puts "implementing the quality system" above "make line go up" is degraded.

> they did not design it such that it could be safely “opened” and “closed” without special care

Silly take. There is nothing wrong with the design of the door plug, which as I understand it is over twenty years old with no other reported failures. "Special care" is standard procedure in aviation.

By this logic the wings/engines/etc. are all faulty because if you don't install the bolts, they might fall off.

The failure here is that the door was not reinspected after the bolts had been removed to “open” it. A reinspection would be required if had been “removed”, and I’d bet that wings are always inspected for proper construction and installation (because there’s no way to “open” the wings).

I don’t believe the parent comment is saying the design is poor, it’s about the process during assembly and maintenance.

> "Special care" is standard procedure in aviation.

Does not compute

Old, established design does not equal good. You should know that from the software world. It seems obvious now that a door plug design that has the same failsafe at pressure of the actual doors would be a good improvement.

I think we'd be having a similar discussion if a door opened unexpectedly during flight.

I think the message of the rest of the comment thread is that a door has two states, "open" and "closed", and the processes around those states know about both of them and handle them appropriately.

Whereas a door plug can't be opened and only has one state, "installed", but the internal processes treated it as if it were a door, generating the documentation that would be appropriate for opening and closing a door (nothing) rather than the documentation that would be appropriate for removing and reinstalling a structural element.

Then, when the door plug wasn't reinstalled correctly, there was no system checking whether it had been "closed", because that concept doesn't apply to door plugs. Whereas an actual door, if it had been left open, would still have generated no relevant documentation, but the plane wouldn't have taken off in that state because the problem would have been obvious.

Oh the process and procedure for generating that documentation exists, it was just not followed.

The process for checking that the door plug bolts are correctly installed was simply skipped, as nominally no work had been done on it due to it not being marked as worked on. So it was not re-inspected.

I’m sure the process exists. But I can understand how an employee could mess it up. If some fairly common work on an airplane involves opening a door, I imagine it’s okay to open and close the door without documenting it. (Just like (I imagine) turning on and off some lights or locking and unlocking a door, etc.) But now there’s a special kind of door (that’s really a plug but works a bit like a door and is literally called a “door plug”), and opening it involves removing four bolts but does not involve removing it completely from the fuselage. So, in a culture where there isn’t a checklist that gets followed for everything, they think “I opened the door (plug)” instead of “I partially removed the door (plug)”, and then they access the rivets (and document that!), and then they sloppily “close the door (plug)” and it is indeed “closed”. But they might not be thinking “I reinstalled the door (plug),” and they don’t check the checklist or fill out the form, and no one ever tracked those four bolts, and a near-catastrophe occurs.

So one might argue that calling this thing a door (plug) and “opening” it is a mistake. And one might argue that a design that “closes” a bit like a door but isn’t correctly installed when it looks closed is a poor design.

It is not the rivets, but the door plug gasket that got damaged while dealing with the damaged rivets.

That gasket got changed, but they did not mark that they had done work on the door, requiring reinspection.

Because closing a door doesn't mean working on it, right?

You can't normally open a regular door in flight as the air pressure prevents it. This is a good feature!

I honestly think the flaw is in the name. It's /not/ a door. It's a temporary hole in the airframe that's used when the interior is installed, and it can be _converted into a door_ if the airline/regulations require additional entry/egress points.

Now they call it a "door plug", and the technician working on it searched the QA SOP document for the right procedures and searched for "door" and "open" and got the SOP for "opening a door", which requires zero documentation after the work is done.

I'l know it's contrived, but it's so stupid that it might just be what happened.