Originally Posted by
megan
At night the USN required oxygen above 5,000, 10,000 day, if my aging memory recalls correctly.
Not sure your recall is up to scratch this morning.
The requirement for unpressurized aircraft in the NATOPS is 10,000' and above. Our usual ceiling / limit even with oxygen for unpressurized cockpits was 25,000 feet.
*scratches head*
Not sure where you got the 5,000 from, but if you flew jets with the USN back in the very old days there may have been a rule (type specific to the A-4 perhaps?) about that in one of the manuals.
If I can find an old T-45 NATOPS (I used to have one in e-form some years ago) I'll see if I can find a ref to "get your O2 mask on by 5,000 because ..." I don't recall that being in the brief on the few occasions I got to fly in one.