Hypoxia in pressurized cabin

[AngelAtTheTomb]

This is a very, very minor issue, but I've noticed something I believe is not accurate to the aircraft.

 

I keep forgetting to switch on the oxygen when doing a cold start (I know, I know), and start noticing the "hypoxic" blur effect at about 22-24,000 feet.

 

However, the F-14 has a pressurized cockpit. According to the NATOPS manual (page 2-165), the pressure altitude up to 25,000 feet should be 8,000 feet (where obviously hypoxia is not an issue), and then increases to a 5psi differential. With an intact, pressurized canopy, you really shouldn't see hypoxia develop until the aircraft is up around 50,000 feet.

 

Yes, I know I should just remember to turn on the oxygen.

[RustBelt]

You set the air source to "BOTH"? If not, you aren't in a pressurized cockpit.

And also technically your gun could catch on fire.

[Golo]

Its the mask, you cant breath normally when you have mask on without oxygen flow (so ive heard in one F/A-18 forum topic) and since we can not remove mask make sure you have oxygen on even if the cockpit is pressurized.

[RustBelt]

Ahhhhh neat!

[WarthogOsl]

I recall reading about someone who actually died because their O2 wasn't flowing and they couldn't get their mask off (or perhaps passed out before they realized what was happening).

[RustBelt]

Yea there’s been a number of Hypoxia issues due to the OBOGS systems in F/A-18s and I think Strike Eagles not actually generating (concentrating really) Oxygen. So pilots were breathing oxygen poor air that “felt” like the system was working, right up until they passed out.

Boeing insists it’s a maintenance problem because Boeing can do no wrong as we all know.

[KlarSnow]

Strike eagles don't have OBOGS, they have MSOGS, different system. The strike eagle issue which was a few years back was due to a spate of faulty valves in the regulators, MSOGS worked and works fine.

The solution to all of these problems btw is to do what aviators have pretty much always done, drop your mask and breathe normally as long as the cabin altitude isn't too high. 

The issue where someone suffocated was a familiarization flight, so somebody in a jet who was not familiar with the mask, helmet and regulator.

[AngelAtTheTomb]

This is all very interesting for the real world, but I don't think it really pertains to the issue at hand.

 

I've tried a few other DCS jets with pressurized cockpits (F-18, F-16) and the pilot doesn't exhibit a hypoxic effect when the cabin alt is below about 18,000 feet. The F-14 has a cockpit alt gauge right there, reading 8,000 feet, and the pilot still goes hypoxic.

 

I know this is a pretty niche bug, but with a more complete damage model - oxygen system failure with an intact canopy, say - it could become important.