Boeing is having a rough time of it right now, with parts falling off its planes left, right and center. Just last week, a wheel came loose and smashed through a car, and earlier this year the door from a 737 Max aircraft broke off mid-flight. That mid-air disaster sparked an audit from the Federal Aviation Administration, which has gone far from well.
Not to me. Absence of QA allows faulty parts to make it into a plane, it does not explain why there are faults in the first place. For doors and wheels popping off there have to be either lethal part design mistakes, parts made from play doh instead of aluminium/steel, or the people on the assembly line throwing fasteners in the bin instead of putting them on. It’s not like a door pops of because its seal touched soap once and somebody poked an unverified piece of plastic at it. Especially in aviation, where you need to have redundancies.
I think it’s an issue of tolerance. They should be using gauges to test the fit, because hotel keycards can vary in thickness. Gauges are stupid cheap compared to the cost of the plane. It’s evidence of cost-cutting bullshit.
Same with using dish soap as a lubricant. It’s the wrong material for the job. Soap leaves a residue, and dissolves other lubricants. If there’s supposed to be lubricant in the door, the soap is a bad choice. If there isn’t supposed to be a lubricant in the door, then soap is a bad choice. It’s like Schrodinger’s lubricant. You won’t know if it’s a problem until it’s a problem.
No manufacturing process or material design is perfect. You get as close as possible, and then QA catches the mistakes.
For Boeing, it sounds like they didn’t try very hard to perfect their processes, and then didn’t bother with QA.