Aircraft gas turbine engine with control vanes for counter rotating low pressure turbines

An aircraft gas turbine engine assembly comprising:

• a high pressure rotor including a high pressure turbine drivingly connected to a high pressure compressor by a high pressure shaft and rotatable about an engine centerline,
• a low pressure turbine having a low pressure turbine flowpath and located aft of said high pressure rotor,
• said low pressure turbine including counter rotatable low pressure inner and outer shaft rotors having low pressure inner and outer shafts respectively which are at least in part rotatably disposed co-axial with and radially inwardly of said high pressure rotor,
• said low pressure inner shaft rotor including first low pressure turbine blade rows disposed across said low pressure turbine flowpath and drivingly connected to a first fan blade row by said low pressure inner shaft,
• said low pressure outer shaft rotor including second low pressure turbine blade rows disposed across said low pressure turbine flowpath and drivingly connected to a second fan blade row by said low pressure outer shaft,
• at least one booster drivingly connected to one of said low pressure inner and outer shafts and axially located between said first fan blade row and said high pressure rotor,
• said first and second fan blade rows disposed within a bypass duct radially outwardly bounded by a fan casing,
• said first low pressure turbine blade rows including at least one first interdigitated turbine blade row disposed between at least one second pair of adjacent ones of said second low pressure turbine blade rows,
• said second low pressure turbine blade rows including at least one second interdigitated turbine blade row disposed between at least one first pair of adjacent ones of said first low pressure turbine blade rows, and
• at least one row of non-rotatable low pressure vanes disposed across said low pressure turbine flowpath between a third pair of adjacent ones of said low pressure first and second turbine blade rows.