ALTITUDE PRESELECT PANEL.

In the approach mode, the light and sound remind the pilot that he is approaching the selected altitude irrespective of the autopilot being engaged or not. If the autopilot is engaged, the APS can be set in AUTO and the aircraft will automatically level off at the desired altitude. The autopilot will revert to ALT HOLD and maintain the altitude. The APS will simultaneously trip to MAN and to the deviation mode. With the APS set to MAN, the pilot has to perform the level-off.

When the aircraft has reached the pre-selected altitude (in AUTO or MAN), the system switches over to deviation mode and will alert the pilot if the aircraft deviates from the selected altitude. The APS is always in MAN during this mode and consequently not connected to the autopilot.

FAIL LIGHT

- Comes on flashing to indicate power failure.
- Comes on flashing when altitude preselect light is pushed for test.

APS switch.

- AUTO. Provides altitude alert and capture of selected altitude. The altitude preselect light on L/P main panel, will come on steady and the the audio tone will sound for 2 s at 700 ft from selected altitude.
The altitude preselect light will come on flashing and the audio tone will sound for 2 s if the aircraft deviates from the selected altitude by 200 ft.
- MAN. Provides a reminder for manual level-off at selected altitude.

ALT KNOB.

Before setting a new altitude - always press the ALT knob to prevent nuisance warnings.
Pressing the knob will also reset the system and trip the APS switch to MAN.

BARO KNOB

Turn to set pressure as applicable. The autopilot will level-off at the altitude set according to this pressure, NOT the pressure set on the altimeter.