US Patent 10301031 Synchronization of aircraft engines

Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.