US Patent 11015532 Parallel starter/generator and air turbine starter

A system for starting a turbine engine is provided. The system may comprise a gearbox, an electric starter, and an air turbine starter. The gearbox may have a gearbox input shaft. The gearbox may be coupled to the turbine engine. The gearbox input shaft may be coupled to a spool of the turbine engine. The electric starter may have an electric-starter shaft. The electric-starter shaft may be coupled to the gearbox input shaft. The air turbine starter may have an air-turbine-starter shaft. The air-turbine-starter shaft may be coupled to the gearbox input shaft. The electric-starter shaft and the air-turbine-starter shaft may be radially displaced, circumferentially displaced, or both radially and circumferentially displaced, with respective to an axis of the turbine engine, from one another. The electric starter may be a starter-generator connected alternatively between an auxiliary power source and an auxiliary load.