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FTA: > Had we gone just a few thousand more feet up (around 11,000-12,000 feet) we would have needed oxygen masks!

Really? I was roaming around at the top of Mauna Kea last summer (14K'), and hiked to the top of Mt Lassen too (10.5K'), but never felt the need for ozygen masks.

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Regulations require it, also air likes to cling to to the surface, plus you had a chance to acclimate and/or are experienced with such a thing.

The regulations actually don't require it. Under FAA rules for general aviation ("Part 91"), you need oxygen between 12,500 and 14,000 feet if you remain there for more than 30 minutes, and it's only once you climb above 14,000 feet that the pilot unequivocally has to have it. You need to get to 15,000 feet before the passengers have to have oxygen provided.

(More: http://www.faa.gov/pilots/safety/pilotsafetybrochures/media/...)

Yup this is right.

Additionally, a cold winter night means dense air which means more oxygen. As far as his lungs/brain are concerned, it's not 7,500 feet, it's more like 6,000 feet.

Ya when skydiving we always exited between 12 and 14k. Only at 15k did you need a mask on the ride up.

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