General Aviation pilots in unpressurized aircraft are required by the FAA to use oxygen above approx. 12,000 feet.
AND ABOVE ONLY
5,000 ft at night !!!
The retina is very sensitive to lower O2 pressure. Because color vision at night begins to deteriorate above just 5,000 ft, the FAA recommends general aviation pilots in non-pressurized aircraft use O2. Most do not.
I once had an arguement with an old pilot in the front row when I was giving a medical talk about hypoxia. He stated that he never had a problem landing at night at his usual place. That's the problem, add a new situation, like new runway, odd lighting around the airport, bad weather, etc, and it might not be so easy. I could not get him to stop badgering me during my talk, so I finally resorted to the line from Top Gun, where Charlie ( Kelli McGinnis) tells Maverick (Tom Cruise), "The Pentagon sees to it that I know more than you."
Brought the house down.
