Aeronautical Code signals
The Aeronautical Code signals are radio signal codes. They are part of a larger set of Q Codes allocated by the ITU-R during the International Telecommunication and Radio Conferences in Atlantic City 1947 in Appendix 9 "Miscellaneous Abbreviations and Signals to be used in Radiocommunications", and documenten in the International Radio Regulations, Section I. Q Code. The QAA–QNZ code range includes phrases applicable primarily to the aeronautical service, as defined by the International Civil Aviation Organisation.
First defined by ICAO in ICAO Doc-6100-COM/504/1" "Communication Codes and Abbreviations. Q Code" published 1952.April.01 and today superceeded by ICAO Doc-8400 "Procedures for Air Navigation Services, ICAO Abbreviations and Codes". The majority of the Q codes published in ICAO Doc-6100 have slipped out of common use; for example today reports such as QAU and QAZ would be voice or computerized transmissions. But several remain part of the standard ICAO radiotelephony phraseology in aviation.
| Code | Meaning | Sample use |
| QFE | The pressure set on the subscale of the altimeter so that the instrument indicates its height above the reference elevation being used | Runway in use 22 Left, QFE 990 hectopascals |
| QFF | Atmospheric pressure at a place, reduced to MSL using the actual temperature at the time of observation as the mean temperature. | |
| QNE | During conditions of exceptionally low atmospheric pressure it is not possible to set QFE or QNH on some aircraft altimeters. In these circumstances an aerodrome or runway QNE can be requested. The QNE is the reading in feet on an altimeter with the sub-scale set to 1013.2 hPa when the aircraft is at aerodrome or touchdown elevation. | - |
| QNH | The pressure set on the subscale of the altimeter so that the instrument indicates its height above sea level. | Request Leeds QNH |
| Code | Meaning | Sample use |
| QDM | Magnetic bearing to a station | request QDM |
| QDL | Series of bearings taken at regular intervals | |
| QDR | Magnetic bearing from a station | request QDR |
| QFU | Magnetic bearing of the runway in use | Runway 22 in use, QFU 220 |
| QGE | Distance | request QGE |
| QGH | Controlled Descent through Clouds | |
| QTE | True bearing/track from a station | request QTE |
| QTF | Position in relation to a point of reference or in latitude and longitude | |
| QUJ | True bearing/track to a station | request QUJ |
| Code | Meaning | Sample use |
| QGH | controller-interpreted DF let-down procedure, on UHF or VHF |