VOR CDI Centralise RNAV

In order to centralise the deviation needle, there must be no difference between the selected track and either the QDMQDM —Magnetic bearing from an aircraft to a beacon or station or the QDRQDR —Magnetic bearing from a beacon or station to an aircraft. This is because the deviation needle is centralised when you are directly on the selected track or on the reciprocal of the selected track.

A simple way to remember this is as follows: if you want to centralise the needle with a TO indication, set the QDMQDM —Magnetic bearing from an aircraft to a beacon or station as the selected track. If you want to centralise the needle with a FROM indication, set the QDRQDR —Magnetic bearing from a beacon or station to an aircraft as the selected track. To centralise with TO, set QDMQDM —Magnetic bearing from an aircraft to a beacon or station, with FROM, set QDRQDR —Magnetic bearing from a beacon or station to an aircraft.