the same time as the gas turbine starter engine is acceler-ating, the exhaust gas is being directed, via nozzle guide vanes, onto the free-power turbine to provide the drive to the
main engine. Once the main engine reaches self-sustaining speed, a cut-out switch operates and shuts down the gas turbine starter.
As the starter runs down, the clutch auto-matically disengages from the output shaft and the main
engine accelerates up to idling rpm under its own power.