Originally Posted by
1peter
Very basic question from a student: GA pilots are urged to fly 5,000 or below at night, in order to preserve night vision. As many large transport jets can not pressurize to anywhere near 5,000, why do transport pilots get to fly at night? Is night vision less important in transport flying? Example: Boeing 767, 6,900' cabin pressure at 39,000'.
You aren't urged to stay at 5000' or below at night, just recommended to have oxygen for vision above those altitudes. "Urged" is a pretty strong word and black things at night are usually the earth at some ground level. Transport can pressurize to 5000', if it's within the max differential PSI for the altitude they are flying, but they may pressurize at a higher cabin alt if flying higher where the max differential does not allow. Also, a lot of GA pilots, probably more-so than airline pilots, may be smokers, not very fit, from sea level, etc. due to less regulation and they don't usually experience going up to 8000 PA like some airline pilots do every day. Lastly, transport category aircraft have much more redundancy, two pilots, following GS down on the approaches, always on airways or segments with minimum altitudes for terrain clearance, etc. Equipped with TAWS.