GA 5,000' Hypoxia
#1
New Hire
Thread Starter
Joined APC: Nov 2016
Position: Student
Posts: 1
GA 5,000' Hypoxia
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'.
#2
Gets Weekends Off
Joined APC: Feb 2015
Position: Downward Dog
Posts: 1,877
That is a good question.
Depending on the aircraft cruise alt cabins can be kept between 5-6k. 5k is a general guideline, hypoxia will affect people in many different ways.
(Opinion) Also night vision unfortunately isn't as stressed in airplanes heading for class A airspace. Many of these cockpits are designed with lots of white light too. Night vision is important but not as import as in a c152 around 1000 feet.
Depending on the aircraft cruise alt cabins can be kept between 5-6k. 5k is a general guideline, hypoxia will affect people in many different ways.
(Opinion) Also night vision unfortunately isn't as stressed in airplanes heading for class A airspace. Many of these cockpits are designed with lots of white light too. Night vision is important but not as import as in a c152 around 1000 feet.
#3
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'.
#4
Disinterested Third Party
Joined APC: Jun 2012
Posts: 6,021
I grew up and learned to fly in a location where my house, let alone field elevation or any flight altitude, was above the FAA recommendation for oxygen at night. Were I to have adhered to that guideline, I'd have needed oxygen to go to bed at night, drive, or walk about town, let alone fly. That's a ridiculous notion.
Why do pilots in pressurized cockpits not utilize oxygen at cabin pressure altitudes of 5,000' or higher? Despite the FAA's extremely conservative recommendation, no regulatory requirement exists for oxygen at that altitude.
Why do pilots in pressurized cockpits not utilize oxygen at cabin pressure altitudes of 5,000' or higher? Despite the FAA's extremely conservative recommendation, no regulatory requirement exists for oxygen at that altitude.
#5
I would agree it depends on your personal physiology to a large degree. Altitude acclimation is a factor, and age, fitness, and smoking are big factors.
If you're doing the kind of flying where night vision could be critical (not most 121) then you might benefit from supplements, especially if you eat like crap.
If you're doing the kind of flying where night vision could be critical (not most 121) then you might benefit from supplements, especially if you eat like crap.
#6
Gets Weekends Off
Joined APC: Feb 2008
Posts: 19,273
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'.
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