Dual input drive AGB for gas turbine engines

An aircraft gas turbine engine comprising:

• at least a main shaft driven by a turbine rotor;
• a tower shaft disposed at a non-zero angle with respect to and operatively connected to the main shaft and first and second bevel gears mounted on the tower shaft, the tower shaft rotating together with said first and second bevel gears at a first rotational speed;
• an accessory drive gearbox including co-axially disposed first and second shafts, the first and second shafts defining a common rotational axis intersecting a rotational axis of the tower shaft, a third bevel gear mounted on the first shaft and meshing with the first bevel gear on the tower shaft, and a fourth bevel gear mounted on the second shaft and meshing with the second bevel gear on the tower shaft, the first shaft rotating at a second rotational speed lower than the first rotational speed and the second shaft rotating at a third rotational speed higher than the first rotational speed;
• at least one accessory device driven at a rotational speed lower than the second rotational speed by the first shaft through a pair of spur gears;
• and
• an integrated starter generator located outside of and mounted to the accessory drive gearbox, the integrated starter generator being driven by the second shaft at the third rotational speed during engine operation.