Sudden Disruption in Flight Controls

[Hester40MT]

@DrearyCoyote453

while flying autopilot with Altitude Hold. I tried to increase or decrease the altitude by turning the adjusting knob but not effect.

Depending on aircraft:

1. Set AP to ON
2. Increase/Decrease target altitude as required, using the ALT knob.
3. Select the AP ALT mode to ON. Nothing happens at this point.
4. Select the AP VS mode to ON. Still nothing happening.
5. Increase/Decrease Vertical Speed using the “NOSE UP” / “NOSE DN” buttons on the MFD to increase/decrease climb rate - whether your target altitude is above or below current altitude.