Final answer:
In suspected icing conditions, the Altitude Hold function of the autopilot should be turned off to allow the pilot to manually control the aircraft and respond to changes in performance caused by the ice accumulation.
Step-by-step explanation:
If icing is suspected, it is generally advisable for a pilot to turn off the Altitude Hold function of the autopilot. This is because ice accumulation can alter the weight and balance of the aircraft, as well as affect the aerodynamic properties, which can lead to unreliable performance when altitude hold is engaged. Icing conditions can cause significant changes in the aircraft's performance, and the autopilot might struggle to maintain a constant altitude, potentially leading to a dangerous situation.
In the interests of safety, the pilot would need to switch to manual control to better manage the aircraft's response to the changing conditions. The pilot will need to monitor airspeed and make appropriate control adjustments to maintain safe flight. It is worth noting that when disabling autopilot, all other functions, including heading hold and yaw damp, might also be disengaged, depending on the aircraft type and the situation.