Procedure for NDB let down as given on approach charts.
A non-precision approach carried out with the help of an NDB (nondirectional beacon). The aircraft homes to the beacon and arrives overhead. It turns outbound and flies level for a specific period of time, depending upon the altitude, after which descent is commenced. At a precalculated time, the aircraft turns inbound and homes onto the beacon. It reduces its rate of descent at the check altitude and levels out at the break-off altitude. In some procedures, the aircraft carries out a procedure turn instead of the above procedure. On aeronautical charts, an NDB is shown by the symbol
. See also letdown