US Patent 11999495 Degraded mode operation of hybrid electric propulsion systems

A hybrid electric engine control module (ECU) can be configured to be operatively connected to a hybrid electric aircraft powerplant having a heat engine system and an electric motor system to control a torque output from each of the heat engine system and the electric motor system. The ECU can be configured to determine whether at least one of the electric motor system or the heat engine system are in a normal mode such that one of the electric motor system and/or the heat engine can provide a predetermined amount of torque. The ECU can be configured to switch to a degraded mode if either of the electric motor system or the heat engine system cannot provide the predetermined amount of torque. In the degraded mode the ECU can be configured to control the electric motor system and the heat engine system differently than in the normal mode or to not control one or both of the electric motor system or the heat engine system.