Supplemental O2

[Murdoughnut]

Was studying today and ran across something I hadn't considered.

When the regs say supplemental O2 is required after 30-minute above 12,500 cabin pressure altitude ... is that 12,500 based on my baro setting read off the alitimeter, or is that 12,500 based on a pressure altitude setting of 29.92?

 

[Roger Roger]

Pressure altitude is by definition based off an altimeter setting of 29.92

 

[ppragman]

Was studying today and ran across something I hadn't considered.

When the regs say supplemental O2 is required after 30-minute above 12,500 cabin pressure altitude ... is that 12,500 based on my baro setting read off the alitimeter, or is that 12,500 based on a pressure altitude setting of 29.92?

your body cares about the pressure, however I never flew for a 135 where we routinely masked up above 10k if we weren’t there for more than 30min. Pressure altitude be damned.

I think the FAA recommends that you go onO2 above 8k at night? I never saw anyone in the 1900 or king air go on air, even though we may have had a 10,000’ cabin at 250

i did see guys occasionally smoke, at night, at 250… so yeah