Accessory gearbox

An accessory gearbox for a ducted fan gas turbine engine, the engine having an engine core, a bypass duct, an engine principal rotational axis and a core annulus surrounding the engine principal rotational axis and radially disposed between the engine core and the bypass duct, wherein an engine radial direction is defined as perpendicular to and intersecting the engine principal rotational axis, wherein:

• the accessory gearbox is for location in the core annulus,
• the accessory gearbox has a sequence of spur gears or driving engine accessories,
• for each spur gear, the spur gear is mounted for rotation about a respective spur gear rotational axis that is non-parallel with the engine principal rotational axis, the spur gear rotating within a respective spur gear rotational plane perpendicular to the spur gear rotational axis, the spur gear rotational plane intersecting said spur gear, wherein the spur gear rotational plane is offset with respect to the engine radial direction.