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..
By average commercial airline plane, I assume you are referring to large passenger jetliners such as Boeing and Airbus products. The takeoff speed of such aircraft varies quite a bit, depending on the takeoff weight and the use of high-lift devices like flaps (2) and slats. However, a good average speed range is about 160 mph (260 km/h) to 180 mph (290 km/h). Some typical takeoff speeds for a variety of airliners are provided below. But you might be wondering just how these speeds are determined.