A preflight test is performed upon power application to the computer. This test is a sequence of internal checks that validate proper system operation prior to allowing autopilot engagement. The preflight test (PFT) sequence is indicated by “PFT” with an increasing number for the sequence steps. Successful completion of self test is identified by all display segments being illuminated (Display Test) and the disconnect tone sounding. Following the preflight test, the red P warning on the face of the autopilot may illuminate indicating that the pitch axis cannot be engaged. This condition should be temporary, lasting no more than 30 seconds. The P will extinguish and normal operation will be available. 1. PITCH AXIS, (P) ANNUNCIATOR - When illuminated, indicates failure of the pitch axis and will disengage the autopilot when the failure occurs and not allow engagement of the pitch axis. 2. AUTOPILOT ENGAGE/DISENGAGE (AP) BUTTON - When pushed, engages autopilot if all logic conditions are met. The autopilot will engage in the basic roll (ROL) mode which functions as a wing leveler and in the vertical speed (VS) hold mode. The commanded vertical speed is be displayed in the upper right corner of autopilot display area for three seconds after engagement or if either the UP or DN button is pressed. The captured VS will be the vertical speed present at the moment of AP button press. When pressed again, will disengage the autopilot. For software version 03/01 and later, the AP button must be pressed and held for 0.25 seconds to engage the autopilot. 3. ROLL AXIS (R) ANNUNCIATOR - When illuminated, indicates failure of the roll axis and will disengage the autopilot and not allow engagement. 4. HEADING (HDG) MODE SELECTOR BUTTON - When pushed, will arm the Heading mode, which commands the airplane to turn to and maintain the heading selected by the heading bug on either the DG or HSI. A new heading may be selected at any time and will result in the airplane turning to the new heading. Button can also be used to toggle between HDG and ROL modes. This button will engage the autopilot in units with software prior to software version 03/01. 5. NAVIGATION (NAV) MODE SELECTOR BUTTON - When pushed, will arm the navigation mode. The mode provides automatic beam capture and tracking of VOR, LOC or GPS as selected for presentation on the HSI or CDI. NAV mode is recommended for enroute navigation tracking. NAV mode may also be used for front course LOC tracking when GS tracking is not desired. 6. APPROACH (APR) MODE SELECTOR BUTTON - When pushed, will arm the Approach mode. This mode provides automatic beam capture and tracking of VOR, GPS, LOC, and Glideslope (GS) on an ILS, as selected for presentation on the HSI or CDI. APR mode is recommended for instrument approaches. 7. BACK COURSE APPROACH (REV) MODE SELECTOR BUTTON - When pushed, will arm the Back Course approach mode. This mode functions similarly to the approach mode except that the autopilot response to LOC signals is reversed, and GS is disabled. 8. ALTITUDE HOLD (ALT) MODE SELECT BUTTON - When pushed, will select the Altitude Hold mode. This mode provides tracking of the reference altitude. The reference altitude is the altitude at the moment the ALT button is pressed. If the ALT button is pressed with an established VS rate present, there will be altitude overshoot (approximately 10% of the VS rate), with the airplane returned positively to the reference altitude. This button will engage the autopilot in units with software prior to software version 03/01. 9. VERTICAL TRIM (UP/DN) BUTTONS - The action of these buttons is dependent upon the vertical mode present when pressed. If VS mode is active, the initial button stroke will bring up the commanded vertical speed in the display. Subsequent immediate button strokes will increment the vertical speed commanded either up or down at the rate of 100 ft/min per button press, or at the rate of approximately 300 ft/min per second if held continuously. If ALT mode is active, incremental button strokes will move the altitude hold reference altitude either up or down at 20 feet per press, or if held continuously will command the airplane up or down at the rate of 500 ft/min, synchronizing the altitude hold reference to the actual airplane altitude upon button release. (Note that the altitude hold reference is not displayed. The display will continue to show the altitude alerter reference.) 10. ROTARY KNOBS - Used to set the altitude alerter reference altitude; or may be used immediately after pressing the BARO button, to adjust the autopilot baro setting to match that of the airplane’s altimeter when manual adjustment is required. (In some installations the baro setting is automatically synced to that of the altimeter.) 11. BARO SET (BARO) BUTTON - When pushed and released, will change the display from the altitude alerter selected altitude to the baro setting display (either IN HG or HPA) for 3 seconds. If pushed and held for 2 seconds, will change the baro setting display from IN HG to HPA or vice versa. Once the baro setting display is visible the rotary knobs may be used to manually adjust the baro setting if automatic baro correction is not available. 12. ALTITUDE ARM (ARM) BUTTON - When pushed will toggle altitude arming on or off. When ALT ARM is annunciated, the autopilot will capture the altitude alerter displayed altitude (provided the aircraft is climbing or descending in VS to the displayed altitude). When the autopilot is engaged, ALT arming is automatic upon altitude alerter altitude selection via the rotary knobs. Note that the alerter functions are independent of the arming process thus providing full time alerting, even when the autopilot is disengaged. 13. ALTITUDE ALERTER/VERTICAL SPEED/BARO SETTING DISPLAY - Normally displays the altitude alerter selected altitude. If the UP or DN button is pushed while in VS hold, the display changes to the command reference for the VS mode in FPM for 3 seconds. If the BARO button is pushed, the display changes to the autopilot baro setting in either IN HG or HPA for 3 seconds. NOTE: This display may be dashed for up to 3 minutes on start up if a blind encoder is installed which requires a warm up period. 14. ALTITUDE ALERT (ALERT) ANNUNCIATION - The ALERT annunciate is illuminated 1000 ft. prior to the selected altitude, extinguishes 200 ft. prior to the selected altitude and illuminates momentarily when the selected altitude is reached. Once the selected altitude is reached a flashing ALERT illumination signifies that the 200 ft. “safe band” has been exceeded and will remain illuminated until 1000 ft. from the selected altitude. Associated with the visual alerting is an aural alert (5 short tones) which occurs 1000 feet from the selected altitude upon approaching the altitude and 200 feet from the selected altitude on leaving the altitude. 15. PITCH TRIM (PT) ANNUNCIATION - A flashing PT with arrows indicates the direction of required pitch trim. A solid PT without an arrow head is an indication of a pitch trim fault. During manual electric trim operation (autopilot disengaged), detection of a stuck MET switch will be indicated by a solid PT. When the fault is corrected, the annunciation will extinguish. 16. PITCH MODE DISPLAY - Displays the active and armed pitch modes (VS, ALT, ARM, ALT and GS). 17. ROLL MODE DISPLAY - Displays the active and armed roll modes (ROL, HDG, NAV ARM, NAV, APR ARM, APR, REV ARM, REV, GS ARM). Also displayed will be flashing AP annunciation (5 seconds) at each autopilot disconnect accompanied by an aural tone (for 2 seconds). 18. AUTOPILOT ENGAGED (AP) ANNUNCIATION - Illuminates whenever the autopilot is engaged. Flashes during pilot initiated or automatic disengagement. Only applicable for software versions 03/01 or later. Note: VS command value will be displayed during Control Wheel Steering (CWS) and for three seconds following VS engagement or pressing the UP or DN button. Both altitude and vertical speed utilize the same display area. Altitude is always displayed except during vertical speed selection. If the VS command value is not displayed, pressing (and releasing) the UP or DN button will not change the indicated altitude reference but will display the VS command value. BARO setting - CHECK. depressing the BARO button will display the baro setting for three seconds. Upon successful completion of preflight test, the baro display will flash. 1. BARO setting - Enter barometric setting using the rotary knobs OR if correct as displayed, press BARO. Baro unit conversion The barometric pressure display can toggled between IN HG and HPA as needed by the pilot. 1. BARO button - Press and hold for two seconds. Note: The ALERT annunciation is illuminated 1000 ft. prior to the selected altitude, extinguishes 200 ft. prior to the selected altitude and illuminates momentarily when the selected altitude is reached. Once the selected altitude is reached, a flashing ALERT illumination signifies that the 200 ft. “safe band” has been exceeded and will remain illuminated until 1000 ft. from the selected altitude.