Cabin Atmosphere Control Systems (Refer to Figure 14.) One hour after an oxygen system was charged for a leakage check, the oxygen pressure gauge read 460 PSI at 63°F; 6 hours later the temperature was 51°F. (A 5 PSI change is the maximum allowable in a 6-hour period.) What pressure gauge readings would be acceptable to remain within the allowable limits? a. 445 to 450 PSI. b. 446 to 450 PSI. c. 455 to 460 PSI. The