In the preamble to the final Respiratory Protection Standard, OSHA discussed extensively its rationale for requiring that employees breathe air consisting of at least 19.5 percent oxygen. The following excerpt, taken from the preamble, explains the basis for this requirement: Human beings must breathe oxygen . . . to survive, and begin to suffer adverse health effects when the oxygen level of their breathing air drops below [19.5 percent oxygen].
- The Tu-144 supersonic transport was the fastest commercial jet plane at Mach 2.35 (1,555 mph, 2,503 km/h). It went into service in 1975, but soon stopped flying. The Mach 2 Concorde aircraft entered service in 1976 and flew for 27 years..
It depends on a number of factors such as the gravity of the planet it's flying on, the atmospheric composition like is the atmosphere made of methane or nitro-oxide. Also it depends on who is flying the plane. If it's a jihadist it is probably flying really fast (800 mph) because they are likely trying to crash the plane. If it is an old person the speed is probably low (250 mph) because they are old. If it is a woman chances are the plane never successfully took off because woman can't fly.