How do you explain the difference between LAFCS-RAFCS and COUPLED LEFT, COUPLED RIGHT?
Here is a few pointers on ENGAGE logic from a Honeywell quick troubleshooting guide (my comments in red):
SPZ-8000 Autopilot Engage Logic
What is needed to satisfy the engage mode:
Stall warning not active (2 on the 900)
TCS P/B not pushed
YD Quick-disconnect P/B not pushed
AP Quick-disconnect P/B not pushed
Go-around P/B not pushed
Manual Trim not active (Also, Emergency trrim in the pedistal on the 900)
Ground Engage Inhibit not active (no WOW engage allowed on the 900)
Servo Power Valid
What takes place when the A/P is engaged:
The FZ-800 is allowed to control the servos.
What components are part of the engage command:
YD Quick-disconnect P/B
AP Quick-disconnect P/B
Manual Trim P/B
What is need to satisfy the disengage mode:
To have any of the engage signals change state.
What takes place when the A/P is disengaged:
The FZ-800 is not allowed to control the servos.
What components are part of the disengage command:
Same as engage.