Oxygen Question

[Headwind]

If you must wear the mask above 410 and above 350 if a crew member must vacate their station - what about a single pilot jet flying at 370 or390? Is there a REG to cover this?

 

[Andy Neill]

Since you appear to be talking Part 91 Operations, I would guess the same section from which you got the numbers in your question:

91.211 Supplemental oxygen.
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(b) Pressurized cabin aircraft. (1) No person may operate a civil aircraft of U.S. registry with a pressurized cabin --
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(ii) At flight altitudes above flight level 350 unless one pilot at the controls of the airplane is wearing and using an oxygen mask that is secured and sealed and that either supplies oxygen at all times or automatically supplies oxygen whenever the cabin pressure altitude of the airplane exceeds 14,000 feet (MSL), except that the one pilot need not wear and use an oxygen mask while at or below flight level 410 if there are two pilots at the controls and each pilot has a quick-donning type of oxygen mask that can be placed on the face with one hand from the ready position within 5 seconds, supplying oxygen and properly secured and sealed.

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From what I see, if I were flying single pilot under Part 91 at FL390, I would need to wear the mask at all times at that altitude.