P-ceiling vs. T-ceiling

[Sapper]

Originally Posted by Paul Sharp

My 1967 T337B has factory O2 and is certified to 33K feet. I don't think that a demand diluter system is actually required above 25K feet, but it is highly recommended.

I think the most limiting factor these days for the T models is the 25K ceiling more or less implemented by the new RVSM regs.

RVSM is FL290 - FL410, so you could go up to FL280.