L-1011 Autoflight: Localizer Arm, Capture and Track (22-30)

Localizer mode also allows an early switch from VOR to ILS guidance when the terrain surrounding the airport is such tat the localizer beam is usable a substantial distance out, while avoiding the possibility of a high altitude glideslope capture.

Either heading mode, heading select or heading hold (CWS), can be used to established the localizer intercept angle.

Engage localizer mode by tuning the ILS frequency on the desired VHF NAV receiver and dialing in the corresponding inbound front course in the window of the NAV MODE Panel.

When localizer capture maneuvering guidance starts, the LOC ARM message on the AFCS MODE annunciator changes to LOC. If heading select was used for pre-capture guidance, the mode is released and the HDG SEL message is removed. Any active pitch axis mode, in this case altitude hold, is retained.

Localizer capture maneuvering is automatically programmed. The maximum bank angle is 28º and the maximum roll rate is 4º per second.

Localizer capture is complete when the bank command becomes less than 5º and at least 25 seconds have elapsed since initiation of capture. The status will change to localizer track, but there will be no annunciation of the change.

The maximum bank angle during localizer track is 10º. The vertical speed mode with an appropriate descent rate set can be used to conduct the remainder of the approach.