by rimunroe | 2025-09-12 15:25:50+00:00
> Well OK, but you starting out by discussing the B-52, so I responded in kind.

...because you used B-52s as an example in your argument that fridges could be made to run maintenance free for decades.

> Unless the documentary I watched was wrong, and of course it could be, that isn't "just replace things because". Instead, it's "if those components need replacement".

Yes, that's how maintenance works. Why would you have thought I was saying it was just for fun? The every-four-years maintenance (PDM) involves a deep inspection of the whole aircraft and replacing parts that are fatigued or otherwise showing signs of wear. I would assume they're doing this because they've found that four years is a good rate to find and replace parts that are going to fail well before they're likely to. Airplane parts wear out after use. Frames experience stress from flying and become fatigued.

Similarly, refrigerant can leak when seals fail. I imagine that on the span of decades outgassing might be a problem too. I haven't dealt with compressor failures personally, but they're mechanical components and I assume eventually lubrication gets to be a problem. Rubber gaskets degrade over time. Fungus/algae can grow in the lines used to drain condensation to the evaporation pan and eventually block them, causing the fridge to build up ice and eventually leak water. Fans will fail over time because bearings wear or insulation on windings degrade.

> My point is, some of those B-52s are being inspected, but not having much done to them, where as others a lot more.

That inspection involves nearly complete disassembly. Which documentary did you watch? Aerodynamic surfaces and structural elements get replaced from fatigue and wear. Parts get removed because of corrosion (airplanes get exposed to a lot of moisture). New components get introduced because systems get upgraded. This is normal and expected, but it's all maintenance. From an article[0]:

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> Foreman said it typically takes a B-52 between 220 and 260 days to go through depot maintenance, depending on parts availability and whether a bomber has any age-related stress fractures or corrosion that need to be repaired. The Air Force is still trying to figure out how much more time the upgrades might add to that schedule, he said.

> Cracking and other structural issues are common on the six-decade-old B-52, Foreman said, and sometimes require components to be replaced. But the Air Force is used to catching and fixing those problems, he said, and the aircraft should be able last well into the 2050s — perhaps to 2060 — without more in-depth structural upgrades.

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> So you can see why I was specifying how this can be mitigated.

No, I can't, not to the degree you claimed. I don't think your argument about being able to make a maintenance-free-for-decades fridge--pardon the pun--holds water[1], much less without significantly increasing the cost. If you're expecting them to do all the work of discovering issues upfront, why would the cost of doing that not inflate the price significantly? Also, ongoing inspections of the fridge would cost money.

If your argument is that eventually we would be able to make humanoid robots where the maintenance costs are negligible, then sure, maybe. That seems within the realm of possibility.

But again, you said we could make fridges which didn't need maintenance for several decades. I don't think that's within the realm of possibility. You used something (the B-52) which needs regular maintenance as an example of why we should be able to make something else (a fridge) which needs almost none. This is what I was responding to.

[0] https://defensenews.com/air/2024/02/20/tinker-air-force-base...