1. S-TEC 55X --OUT OF BOX FAILURES-- VERIFICATION PROCEDURES

2. OBF’S Steps to handle suspected OBF’s…
Check A/P seating in the tray…
Does computer movement cause a change in operation?
Does computer “feel” loose?
Are LCD segments or backlighting flickering on/off?
Is there a yellow message across the top of the PFD – “NO COMMUNICATION WITH A/P”?
If any of the above symptoms exist
Re-rack the computer.
Check for obstructions in the tray that might prevent full engagement.
Check for pushed back pins in A/P tray connector wiring.
Reboot PFD

3. OBF’S Steps to handle suspected OBF’s… Power up problems…
There are no “error codes” that appear on display.
6 or 7 that appears momentarily in the right corner is normal.
Does a “RDY” annunciation appear after 1 to 2 minutes of power application?
If no “RDY” annunciation check for correct power applied to Turn Coordinator and it’s proper operation. (2 separate C/B’s)
If “RDY” appears but only flashes upon A/P engagement check A/P disconnect circuit to include Stall Warning Module, Stall Warning switch, A/P disconnect switches and circuitry.

4. OBF’S Steps to handle suspected OBF’s… SRV – SR Autopilot (PFD only)
Pitch and Roll problems…
Ensure Heading System placard matches aircraft system installed
PFD A/C – King KCS 55A
Older HSI type display – EDO NSD 360A
Ensure proper part number has been installed.
Pitch and roll gains are different per aircraft type/model.
SRV – SR Autopilot (PFD only)
Pre- G3 aircraft – /
No pitch servo, no auto trim, no Flight Director outputs, no VS mode select on PFD.
Post G3 aircraft T-30 /
A/C 1886 & subs
Includes pitch servo and auto trim.

5. OBF’S Steps to handle suspected OBF’s… SR20 – 55X Autopilot (PFD only)
Pitch and Roll problems, cont…
SR20 – 55X Autopilot (PFD only)
Pre- G3 aircraft – P /
No pitch servo, no auto trim.
Post G3 aircraft T-30 /
A/C 1886 & subs
Includes pitch servo and auto trim.
SR22 – 55X Autopilot (PFD only)
All, except with Roll Servo STC T-30 /
With roll servo installed T-30 /

6. OBF’S Steps to handle suspected OBF’s… Faults that warrant A/P removal
Fail message on computer display.
LCD digits come up garbled or randomly change.
Continuous disconnect tone being emitted.
Switch functions fail to operate.
Backlight inop.
Pitch or roll function not working, perhaps accompanied with smoke from the unit indicates a blown fuse.
CAUTION!! A computer replaced for being INOP in PITCH or ROLL modes usually indicates an external fault. The pitch or roll fuses may immediately blow upon installation of replacement computer, rendering it also inoperative. The pitch servo, pitch and roll trim motors and all associated wiring should be thoroughly checked for shorts prior to installing another computer.