If you are above FL350 single pilot and you only have a mask around your neck, you are in violation of 135.89.

I take my Citation I to FL410 every few flights and with the Pratt engines at that altitude it holds about an 8,000 foot cabin.

The Williams engines are a great upgrade. With a G1000 and the eagle fuel mod, it's a tough airplane to beat for the $.

If you are above FL350 single pilot and you only have a mask around your neck, you are in violation of 135.89.
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Okay, let's try 91.211 then.

When you are operating single pilot above 350, you must be on oxygen. It applies to part 91 operators as well.

Okay, let's try 91.211 then.

When you are operating single pilot above 350, you must be on oxygen. It applies to part 91 operators as well.

So if you are single pilot in this plane or say a new Mustang above 350 you are to have a mask on?

Yes and as every youtube video out there demonstrates everybody does wear one It's a solution in search of a problem. You can count on one hand corporate jet accidents attributed to sudden depressurization...I've often wondered how our old captain would have handled that. It really would have screwed with his smoking. But that was another world, far, far away.

We were two pilots with quick donning masks which we debriefed prior to departure.

I"ll bet that rule is always followed....... A few threads back jet pilots sounded like Boy Scouts about never busting balanced field t/o's, this has to be the same.

Nope, not the same. One is broken all the time, the other is not.

Hey, it's late over here !

Nope, not the same. One is broken all the time, the other is not.

I've heard rumor of the Feds checking 02 gauges on arrival in some instances.

Interesting...

I know of at least one pilot who demos a light jet for the manufacturer who is regularly checked by FAA folks. On multiple occasions they have looked at the O2 gauge and asked him why it was still full and when last service. He went ballistic when he found one guy had tucked his business card way into the mask. Had he pulled it out to quick don, it would have been an issue. His theory was that the inspector planned to look at the plane the next time it went back to that field and see if the card was still there...if so it would be "proof" the pilot wasn't using the mask above FL350. I don't know if he ever approached the inspector, but I do know he filed a report complaining that an inspector had messed with critical to flight safety equipment in a way that might have compromised safety had it not been noted during pre-flight...

I know of at least one pilot who demos a light jet for the manufacturer who is regularly checked by FAA folks. On multiple occasions they have looked at the O2 gauge and asked him why it was still full and when last service. He went ballistic when he found one guy had tucked his business card way into the mask. Had he pulled it out to quick don, it would have been an issue. His theory was that the inspector planned to look at the plane the next time it went back to that field and see if the card was still there...if so it would be "proof" the pilot wasn't using the mask above FL350. I don't know if he ever approached the inspector, but I do know he filed a report complaining that an inspector had messed with critical to flight safety equipment in a way that might have compromised safety had it not been noted during pre-flight...