Mechanical shear fuse for engine motoring system

A motoring system for a gas turbine engine comprising:

• a reduction gear train having an input and an output;
• an electric motor operably connected to the input;
• a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train;
• a mechanical shaft fuse operably connecting the output to the clutch, the mechanical shaft fuse in operation shears when torque on the mechanical shaft fuse is greater than or equal to a selected value, wherein the mechanical shaft fuse includes a plurality of through holes;
• a starter operably connected to the clutch, the starter having an output shaft;
• and
• an accessory gearbox operably connected to the output shaft of the starter.