Functions of the Automatic pilot.

1 PITCH SELECTOR Provides desired operation mode in the pitch axis. MACH HOLD The Mach number existing at the time of engagement is maintained by corrections in pitch attitude. IAS HOLD The speed existing at the time of engagement is maintained by corrections in pitch attitude. VERT SPEED Aircraft vertical speed is controlled by the vertical speed wheel. When other modes are selected, the vertical speed wheel synchronizes to the existing vertical speed. Desired vertical speed is selected by the wheel and the detent position functions as "altitude hold". G/P EXT Reduces glide path signal gain (the A/P reacts somewhat slower). PITCH HOLD The pitch attitude existing at the time of engagement is maintained. 2 VETICAL SPEED WHEEL. In the ALT HOLD (detent)position, existing altitude will be maintained. Vertical speed is selected by moving the wheel towards CLIMB or DESCEND as applicable. 3 TURN KNOB. When the knob is displaced from its detent, the aircraft will bank in the corresponding direction. Bank angle will be proportional to knob displacement and any other lateral control mode will be disengaged. Maximum bank angle 30-35 degree. 4 HDG SEL SWITCH. In ON position, the A/P will steer the aircraft to the heading selected on the left RDI provided the turn knob is in detent position. The heading select mode can be used with either NAV-LOC or ILS mode armed. When beam capture starts, the switch will automatically revert to OFF. 5 SERVOS LEVER. Provides simultaneous engagement and disengagement of the pitch and roll axis. 6 NAV SELECTOR. Provides selection of desired heading or radio NAV mode. R NAV.Previously DOP. Couples the RNAV system to the autopilot. DOP (doppler) was used on the DC8. NAV-LOC. Provides automatic capture of selected VOR-LOC beam. Turn knob must be in detent position. TURN KNOB. Position permits manual change of aircraft heading by means of the turn knob or heading select. ILS. Provides automatic capture of the LOC and GP beams. MAN G/P. Will force the autopilot into GP capture mode. Most often used to bypass the 10 seconds capture phase. During this, the aircraft will descend with 900ft/min. A little bit to high speed and the aircraft will be above the G/P when the real capture occur, resulting in a jerk.