Aviation
Although the majority of the Q codes have slipped out of common use, several remain part of the standard ICAO radiotelephony phraseology in aviation.
Altimeter Settings
| Code | Meaning | Sample use |
|---|---|---|
| QFE | Atmospheric pressure at sea level, corrected for temperature and adjusted to a specified datum such as airfield elevation. When set on the altimeter it reads height. | Runway in use 22 Left, QFE 990 millibars |
| QFF | Barometric 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, 1013.25hPa 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) |
| QDL | Series of bearings taken at regular intervals | |
| QDR | Magnetic bearing from a station | (callsign) request QDR (callsign) |
| QFU | Magnetic bearing of the runway in use | Runway 22 in use, QFU 220 |
| QGE | Distance | |
| QTE | True bearing from a station | True bearing, True bearing, (callsign) request QTE (callsign) |
| QTF | Position in relation to a point of reference or in latitude and longitude | |
| QUJ | True bearing to a station |
Radio Procedures
| Code | Meaning | Sample use |
|---|---|---|
| QGH | controller-interpreted DF let-down procedure, on UHF or VHF |
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