What is the significance of 29.92 inHg (1013.25 hPa) in aviation?

• A. It is the standard sea-level pressure for all flights.
• B. It is the local pressure at the airport.
• C. It is the standard sea-level pressure (QNE) used for flight levels above the transition altitude.
• D. It is the maximum allowable pitot pressure.

Answer: (C)

29.92 inHg (1013.25 hPa) is the standard sea-level pressure used as the reference for altitude when flying at higher levels. This pressure setting, called QNE, is used above the transition altitude so the altimeter is set to a fixed reference instead of local conditions. When you set the altimeter to this standard pressure, the instrument shows flight levels—constant pressure altitude—so aircraft maintain uniform vertical separation regardless of variations in sea-level pressure at different locations. It’s not the local airport pressure, and it’s not a limit on pitot pressure; it’s the standardized reference used to keep high-altitude traffic organized and safe.