What is QNH?

• A. The local altimeter setting that yields altitude above mean sea level.
• B. The local altimeter setting that yields height above the local airfield.
• C. The standard pressure setting of 29.92 inHg.
• D. The altimeter setting not used in flight.

Answer: (A)

QNH is the local altimeter setting that, when dialed in, makes the altimeter indicate your altitude above mean sea level. It’s the sea-level-adjusted pressure for the area, so on the ground it shows roughly the field’s elevation above MSL, and in flight it gives your true height above sea level. This is different from QFE, which is the pressure setting that makes the altimeter read height above the airfield (field elevation) on the ground, and from QNE, which is the standard pressure setting (29.92 inHg or 1013 hPa) used to read flight levels independent of local pressure. The statement about an altimeter setting not used in flight is incorrect; altimeter settings are used throughout flight.