[altrus]

> There are always going to be leaks.

As this seems to be something that's given quite a bit of thought, do you have an idea on what the maximum diameter hole through the fuselage to safely maintain sufficient cabin pressure during cruise flight at, say, PL390? More specifically, what's the maximum rate of pressurization that the cabin pressurization system is designed to support?

[WalterBright]

I have no idea, as I didn't work with the tin benders (structures guys).

But I do know that there can be a hole the size of a quarter and nobody will notice a pressure drop. You're not going to knock an airliner down by punching holes in the fuselage, either (some people think a bullet hole will cause it to pop like a balloon, nothing of the sort will happen).