Gas turbine engine accessory gearbox

An accessory gearbox (60) for a gas turbine engine has a main gearbox housing (188) for receiving a plurality of gears (66) to drive a plurality of accessories. An input shaft (181) has a first bevel gear (180) at an outer end, and extends inwardly to transmit rotation to the plurality of gears (66). A tower shaft (184) has a second bevel gear (182) engaging the first bevel gear (180) to in turn drive the input shaft (181). A tower shaft housing (186) is fixed to the main gearbox housing (188). A method of removing a tower shaft is also disclosed.