Q-code - system developed when air-to ground communication was
by wireless telegraphy, enabling many routine phrases and questions to
be reduced to three letters. Now largely redundant, except these:
- QDM - magnetic bearing to a direction-finding station.
- QDR - magnetic bearing from the station.
- QFE - atmospheric pressure at aerodrome elevation. With its
sub-scale set to the aerodrome QFE an altimeter will indicate height
above that airfield.
- QFU - magnetic orientation of runway in use.
- QNE - reading in feet on an altimeter set to 1013.2 millibars
(standard pressure) when the aircraft is at aerodrome elevation.
- QNH - altitude above mean sea level based on local station
- QTE - true line of position from a direction-finding station.
- QUJ - true bearing
QFI - Qualified Flying Instructor. Also QHI, qualified
Quadrantal Rule - system of cruising altitudes used in UK
uncontrolled airspace below FL250.