Originally Posted by
Hogg
Anyone hear of this procedure?
No. I have been flying 500-series Citations (Bravo, Ultra, Encore) since 15 years and have never heard of that practice. On all the ones that I flew and still fly the oxygen tank shutoff valve is not accessible without using tools anyway, completely out of reach so to say.
Many of these aircraft still carry an emergency oxygen bottle in the cabin though (intended to be used for passengers with health issues). If the pilot of this flight had an issue with his oxygen system he might have tried to get to that emergency bottle. That might explain why he could not be seen in the cockpit.