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Comment by jupp0r | Hacker News Reader

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!

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Which doesn't rule out, say, a design flaw that allows the bolt to loosen over time under certain circumstances.

That's why we have safety wire, which is all over aviation construction.

The Max 9 has been in service since 2018 though, I think if it was a design issue it would have occurred before now. This seems like a Manufacturing QA “escape” to me. Some bolt was either not installed properly or not tightened to the proper spec, QA did not catch it

> The Max 9 has been in service since 2018 though, I think if it was a design issue it would have occurred before now.

That's a bit of a leap. If the bolts are e.g. too soft and have worn out in use, that would be a design issue that would only show up after a period of use.

> IIRC every bolt's torque value needs to be logged any time it's (re)fastened.

So how did this happen if they we checked so recently?

Most likely they were either not installed properly in the first place, or there is some kind of design flaw.

Process issues

Man, if that's not automated how do they keep the numbers from being fudged? That's a lot of bolts, isn't it?

Most of the fasteners on the airframe are probably not bolts, e.g. rivets on aluminum airframes. But yes it's surely still a lot of bolts.

I'm not sure what the standard is in the aviation industry, but things like data-logging torque wrenches exist, and are used in other industrial applications.

They should put the bolt torque values on the blockchain. That'll fix it.

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