Earlier quoted context omitted.
To be fair it seems there is an image of some of the loose bolts: https://nitter.net/ByERussell/status/1744460136855294106 I think this should stick out to an assembly person as not quite right.
That lock nut may not have lined up correctly for some reason and was backed off a bit to get the pin in? That could make it torqued under spec. But also, it doesn't look like that bolt clamps anything so it may not matter if it was a little "loose"..
United finds loose bolts on plug doors during 737 Max 9 inspections
311–320 of 773 posts
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#312Makes you wonder if there was malice involved?
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#313Earlier quoted context omitted.
IIRC every bolt's torque value needs to be logged any time it's (re)fastened. At least that's true for aircraft engine maintenance, not sure if it applies to the assembly process of the airframe, I'd sure hope so!
Which doesn't rule out, say, a design flaw that allows the bolt to loosen over time under certain circumstances.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#314Earlier quoted context omitted.
They generally don't disassemble the entire plane every time they get inspected...
IIRC every bolt's torque value needs to be logged any time it's (re)fastened. At least that's true for aircraft engine maintenance, not sure if it applies to the assembly process of the airframe, I'd sure hope so!
So how did this happen if they we checked so recently?
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#315So, about that Max 10 on which you were hoping to get fast-track approval...
Airbus must be having a fantastic week.
https://www.bloomberg.com/opinion/articles/2024-01-08/alaska...
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#316Earlier quoted context omitted.
They do disassemble the entire plane for heavy maintenance checks every 6-12 years. The MAX 9 has been in operation for just a few weeks though...
That’s pretty incredible. After a heavy maintenance breakdown, what percentage of the plane gets replaced? Or is everything already on a routine maintenance schedule so the intention is to visually identify unexpectedly failing parts?
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#317Earlier quoted context omitted.
Shouldn't the bolts be safety wired after being torqued?
Does wiring bolts actually help? I feel like if a bolt is going to come loose enough such that the wire is all that is holding it in then you have a big problem already. The wire is just delaying the inevitable. A bolt is either fastened or it isn’t. If the wire is all that’s left to hold it, then it isn’t fastened and your parts are being held together with a very weak piece of wire.
https://fastenerengineering.com/what-is-a-castellated-nut-an...
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#318Earlier quoted context omitted.
If Boeing has insufficient competition, they don't have to care because their customers have limited alternatives. If they don't have to care then they don't have to care if their subcontractors care. They also have limited fear of regulators because the US government will be wary about damaging the country's sole supplier in an important industry. Break them up and it's easier for both the market and the government…
And how would you break up Boeing to create more competition for civil airliners exactly?
They all have the rights to the existing designs, and can create derivatives, but they don't automatically get the rights to the others' derivatives, so they have the incentive to specialize or develop new designs to find a niche, for the same reason the Boeing 737 isn't an exact clone of the Airbus A320 or vice versa.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#319Earlier quoted context omitted.
There are mutual recognition agreements between the regulators and if the europeans try something like that, the americans can create counter measures to even the field in a mutually undesired spiral. At this moment, the biggest enemy of Boeing is Boeing itself.
I’m not sure I understand what you are getting at. I’m assuming that the US is less likely to demand costly changes to aircraft produced by Boeing because of the implications it would have for their own economy. I wouldn’t trust France to preemptive ground a series of Airbus planes either.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#320Earlier quoted context omitted.
Shouldn't the bolts be safety wired after being torqued?
Does wiring bolts actually help? I feel like if a bolt is going to come loose enough such that the wire is all that is holding it in then you have a big problem already. The wire is just delaying the inevitable. A bolt is either fastened or it isn’t. If the wire is all that’s left to hold it, then it isn’t fastened and your parts are being held together with a very weak piece of wire.
You're much better off with a loose bolt, than a missing one. It'll hopefully make itself known somehow (maybe even just visual inspection) while still remaining somewhat attached, which is better than nothing.