Pitch Operating Modes (Trim Prompting) - Century 4000 Pilots Operating Manual

Automatic 45-degree intercepts, selected angle intercepts, crosswind correction and tracking are as
described in the APR mode accept that response to radio signals is reversed.
NOTES
When using an NSD-360A, NSD-1000 or other HSI always set the radio course pointer to the inbound
front course localizer heading.
When using a DG, always set the heading bug to the final approach heading to the airport.
*PITCH OPERATING MODES
*ALTITUDE - ALT mode will cause the aircraft to maintain the pressure altitude present at the time of ALT
engagement.
*ALT may be engaged at maximum rate of climb or descent, but for passenger comfort, rate of climb or
descent should be reduced to 1,000 feet per minute or less prior to ALT engagement. Depressing either
the pitch UP or DN switch will shift the AP mode back to ATT mode.
*ATTITUDE - ATT mode places pitch command with the pitch UP and DN switches. Pitch is always
synchronized to the existing aircraft attitude after pitch modification. When engaging the autopilot or
when transferring the system to ATT from ALT, the aircraft will maintain its existing attitude.
*PITCH MODIFIER SWITCHES - The pitch modifier switches are momentary push-
button type, located on the right side of the Mode Programmer, used to modify the
airplane's attitude and to shift the AP from the ALT mode to the ATT mode.
*GLIDESLOPE COUPLING - In the presence of selected APR mode only and other enabling logic, the
glideslope function is fully automatic. Therefore, no GS engage switch is used.
*GS mode may be entered from either ATT or ALT mode, from either above or below the glideslope.
*Capture of the glideslope depends upon satisfying conditions which will complete the arming sequence.
After arming, capture will occur just before glideslope interception so as to rotate smoothly to interception.
This "anticipative capture" point is determined by the rate of closure satisfying a computer equation. In
order for the GS mode to arm, the following conditions must exist simultaneously:
1. No. 1 NAV radio channeled to localizer frequency.
2. Localizer deviation must be less than 90 percent either side of center.
3. A valid localizer signal (no flag).
4. A valid glideslope signal (no flag).
5. APR mode selected.
*When these conditions are met the GS annunciator will illuminate in conjunction with the active pitch
mode annunciator indicating glideslope is armed.
*When "anticipative capturing" occurs, the active pitch mode annunciator will extinguish leaving only the
illuminated GS annunciator to indicate that transition to the glideslope signal has occurred.
*The GS mode may be deactivated by selection of any other pitch mode (ALT, ATT) but automatic
recapture of the glideslope may occur in ALT or ATT modes.
NOTES
The NAV mode should be used when executing a holding pattern ton the localizer to prevent automatic
glideslope coupling.
When radio receiver is tuned to a localizer frequency, the coupler will operate with localizer (APR)
dynamics in the NAV mode.
*CWS MODE (Pitch Sync) - The system is equipped with a control wheel steering switch
located on the horn of the pilot's control wheel. When depressed, this switch will
disengage the roll and pitch servos to allow manual maneuvering.
*When released the system will re-engage in the lateral (roll) mode previously in use.
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