During what conditions is engine synchronization disabled?

Engine synchronization is disabled when the aircraft is on the ground. This is primarily due to the fact that engine synchronization systems are designed to enhance performance and fuel efficiency during flight. When the aircraft is stationary on the ground, there is no need for the engines to work in tandem as they would during flight, where synchronization allows for balanced thrust production and smoother operation.

Aircraft systems particularly manage engine functions to prevent any unnecessary modifications to parameters while on the ground, as this could lead to complications during taxiing or pre-flight checks. The design of engine synchronization limits its operation to airborne conditions where the advantages of synchronized engine operation can be optimized for efficient flight performance.

In contrast, factors such as unbalanced torque could lead to synchronization problems during flight, but are not the reason for synchronization being disabled on the ground.