What? No more 10-14,000 for up to 30min without?
I can remember spending a lot longer than 30 minutes a bit highter than that on more than one occasion. I didn't like having to do it but really had no choice in the matter.
Only one a/c I flew on a regular basis had O2 equipment fitted and when the bottle ran out one day the CP wasn't interested in having it refilled in any great hurry.
You just did what you had to do.
