TRANSMISSION AND METHOD FOR CONTROL OF BOOST SPOOL

A gas turbine engine (10) includes a first spool (16) rotationally coupled to a plurality of accessories via a first gearing (224, 226) and a second spool (12) rotationally coupled to a third spool (14) via a second gearing (210, 212). The first gearing (224, 226) and the second gearing (210, 212) rotate independently and are enclosed within a housing of an accessory gearbox. A method of operating the gas turbine engine (10) includes supplying a first fuel flow rate to a primary combustor (70) associated with the first and third spools and supply a second fuel flow rate a secondary combustor (84) associated with the second spool (12) based on a power lever angle within an intermediate power level range.