The majority of the Q codes have slipped out of common use; for example today reports such as QAU ("I am about to jettison fuel") and QAZ ("I am flying in a storm") would be voice or computerized transmissions. But several remain part of the standard ICAO radiotelephony phraseology in aviation.
Altimeter Settings
Code Meaning Sample use
QFE Atmospheric pressure at a specified datum such as airfield runway threshold. When set, the altimeter reads the height above the specified datum. Runway in use 22 Left, QFE 990 millibars
QFF Atmospheric pressure at a place, reduced to MSL using the actual temperature at the time of observation as the mean temperature.
QNE Atmospheric pressure at sea level in the International Standard Atmosphere (ISA), equal to 1013.25 mbar or hPa and used as reference for measuring the pressure altitude. When flight levels are used as an indication of altitude, 1013.25 hPa is used as mean sea level (QNH).
QNH Atmospheric pressure at mean sea level (may be either a local, measured pressure or a regional forecast pressure (RPS)). When set on the altimeter it reads altitude. Request Leeds QNH
Radio Navigation
Code Meaning Sample use
QDM Magnetic heading to a station (callsign) request QDM (callsign)[12]
QDL Series of bearings taken at regular intervals
QDR Magnetic bearing from a station (callsign) request QDR (callsign)[12]
QFU Magnetic bearing of the runway in use Runway 22 in use, QFU 220[13]
QGE Distance
QGH Controlled Descent through Clouds (Royal Air Force use)
QTE True bearing from a station (callsign) request QTE (callsign)[12]
QTF Position in relation to a point of reference or in latitude and longitude
QUJ True heading to a station
Radio Procedures
Code Meaning Sample use
QGH controller-interpreted DF let-down procedure, on UHF or VHF[14]
Maritime[edit]
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