Altimeter Setting
The altimeter setting is the barometric pressure value (in inches of mercury or hectopascals) set on the Kollsman window of an altimeter to produce a reading of true altitude above MSL at that location. In Canada, the altimeter setting is referred to as QNH.
QNH vs. QNE vs. QFE
- QNH: Local sea-level pressure; set below the transition altitude (18,000 ft in Canada); makes the altimeter read MSL altitude
- QNE: Standard pressure setting 29.92 inHg (1013.2 hPa); set at and above FL180; makes the altimeter read pressure altitude (flight levels)
- QFE: Pressure at aerodrome elevation; makes the altimeter read zero on the ground; rarely used in Canada
Getting the Setting
Current altimeter settings are available from ATIS, AWOS, FIC, and ATC. In cruise flight, request updated settings from ATC or FIC. At uncontrolled aerodromes, use the most recent setting from a nearby reporting station.
On the TC Written Exam
Know QNH, QNE, and QFE; the transition altitude in Canada; and the consequence of flying with an incorrect altimeter setting — a primary cause of CFIT (controlled flight into terrain).
Related Terms
See also: Altimeter, Altitude, Pressure Altitude.