Propeller synchronization

In aviation, propeller synchronization is a mechanism that automatically synchronizes all propellers of a multiengine, propeller-driven aircraft so that they rotate at the same speed.

Propeller synchronization serves mainly to increase the comfort of crew and passengers, since its primary purpose is to reduce the “beats” generated by propellers that are turning at slightly different speeds. These beats can become very irritating to persons inside the aircraft after a time. Synchronization is not normally necessary for proper operation of the aircraft.