Anon Boeing engineer reveals why the 737 door blew off (opens in new tab)

The doors are very heavy, the pressure keeps them in place in only one direction. Without the bolts, only friction from the pressure would hold them up.

I guess presumably because the plug does double-duty as a door depending on the floor plan.

It's up to chance that the door plug could bounce up, and thus ready to open when the pressure builds.

https://www.youtube.com/watch?v=5FcyvFfHsjQ

What seems odd is the springs that assist opening an emergency exit are left in place. Might not have made a difference.

That said, I worked in commercial aircraft engine component repair for years and everything I read in this is 100% plausible to me.

One time we shipped a part back to the customer before it was even done being repaired. It had labels and stickers marking stuff that needed to be done still on it. When the customer got it they emailed us some photos of the markings and said "It doesn't look done to us...". We had to tell them to send it back so we could finish it. Whoops!

Still sounds like a clear case of an unbelievable amount of bad quality from Spirit, and Boeing not pressing the issue until something finally slips through the cracks

> has in the past 365 calendar days recorded 392 nonconforming findings on 737 mid fuselage door installations

which prompted my comment.

then it says that the door in question was re-worked by Spirit employees. It implies that the bolts were removed and not re-fitted, but I don't see evidence that they were ever fitted. Perhaps they were, but then removed by people working for a company that day to day doesn't fit bolts, or perhaps they were never there and the people working for the non-bolt-fitting company didn't see the problem with that.