Wondering if the UAT (Ultimate Air Trap) should (or needs to be) replaced periodically ? Does the sack material break down in any way after a few years of being submerged in kero ? Thanks. Bob

I have had the same BVM uat in my Avonds F15 for years with no problems. Lost count of flights after around 800.
I think it will be the only jet I've had that will die of old age. Some of the wood formers are starting to crumble.

That sock is an automotive fuel pump filter sock. They last indefinitely submerged in gasoline in automotive applications. The only reason to replace it is if it becomes clogged or damaged.

Joe