What is the standard sea level atmospheric pressure expressed in inches of mercury and in pounds per square inch?

• A. 29.92 inches of mercury and 14.69 pounds per square inch.
• B. 29.92 inches of mercury and 15.00 psi.
• C. 30.00 inches of mercury and 14.69 psi.
• D. 29.50 inches of mercury and 14.50 psi.

Answer: (A)

At sea level the standard atmospheric pressure is defined as 1 atmosphere, which equals 1013.25 hPa. In aviation terms this is commonly expressed as 29.92 inches of mercury and about 14.69 pounds per square inch. The option that lists exactly these values matches the standard reference pressure used for altimeter settings and the standard atmosphere. The other choices pair values that are either higher or lower than the standard, so they don’t represent the accepted sea‑level pressure.