A surgical instrument, comprising: a housing assembly; a motor assembly operably supported in said housing assembly; at least one rotary drive system (300, 320) configured for selective operable engagement and disengagement with said motor assembly; a bailout system comprising: a bailout drive train supported by said housing assembly and configured for selective operable engagement and disengagement with said at least one rotary drive system (300, 320); and a bailout handle assembly selectively movable between a stored position within said housing assembly and an actuation position such that, when said bailout handle assembly is in said stored position, said at least one rotary drive system (300, 320) is retained in operable engagement with said motor assembly and when said bailout handle assembly is in said actuation position, said bailout drive train is in operable engagement with said at least one rotary drive system (300, 320), characterised in that said housing assembly further comprises a bailout access panel that is manoeuvrable between a closed position wherein said bailout handle assembly is completely enclosed within said housing assembly in said stored position and an open position wherein said bailout handle assembly is actuatable, wherein said at least one rotary drive system (300, 320) comprises: a system drive shaft rotatably supported by said housing assembly; a driven bevel gear axially movable on said system drive shaft between a first position wherein said driven bevel gear is in meshing engagement with a driver bevel gear of said motor assembly and a second position wherein said driven bevel gear is out of meshing engagement with said driver bevel gear; and a drive system biasing member for biasing said driven bevel gear into said second position and wherein a portion of said bailout access panel is configured to bias said driven bevel gear into said first position when said bailout access panel is in said closed position. a housing assembly; a motor assembly operably supported in said housing assembly; at least one rotary drive system (300, 320) configured for selective operable engagement and disengagement with said motor assembly; a bailout system comprising: a bailout drive train supported by said housing assembly and configured for selective operable engagement and disengagement with said at least one rotary drive system (300, 320); and a bailout handle assembly selectively movable between a stored position within said housing assembly and an actuation position such that, when said bailout handle assembly is in said stored position, said at least one rotary drive system (300, 320) is retained in operable engagement with said motor assembly and when said bailout handle assembly is in said actuation position, said bailout drive train is in operable engagement with said at least one rotary drive system (300, 320), a bailout drive train supported by said housing assembly and configured for selective operable engagement and disengagement with said at least one rotary drive system (300, 320); and a bailout handle assembly selectively movable between a stored position within said housing assembly and an actuation position such that, when said bailout handle assembly is in said stored position, said at least one rotary drive system (300, 320) is retained in operable engagement with said motor assembly and when said bailout handle assembly is in said actuation position, said bailout drive train is in operable engagement with said at least one rotary drive system (300, 320), characterised in that said housing assembly further comprises a bailout access panel that is manoeuvrable between a closed position wherein said bailout handle assembly is completely enclosed within said housing assembly in said stored position and an open position wherein said bailout handle assembly is actuatable, wherein said at least one rotary drive system (300, 320) comprises: a system drive shaft rotatably supported by said housing assembly; a driven bevel gear axially movable on said system drive shaft between a first position wherein said driven bevel gear is in meshing engagement with a driver bevel gear of said motor assembly and a second position wherein said driven bevel gear is out of meshing engagement with said driver bevel gear; and a drive system biasing member for biasing said driven bevel gear into said second position and wherein a portion of said bailout access panel is configured to bias said driven bevel gear into said first position when said bailout access panel is in said closed position. a system drive shaft rotatably supported by said housing assembly; a driven bevel gear axially movable on said system drive shaft between a first position wherein said driven bevel gear is in meshing engagement with a driver bevel gear of said motor assembly and a second position wherein said driven bevel gear is out of meshing engagement with said driver bevel gear; and a drive system biasing member for biasing said driven bevel gear into said second position and wherein a portion of said bailout access panel is configured to bias said driven bevel gear into said first position when said bailout access panel is in said closed position.