A Conair Aviation Convair CV-580 turboprop conversion 340-32 experienced a loss of directional control and subsequent runway excursion during landing at Manning Airport (CFX4), Manning, Alberta. The aircraft sustained significant damage, including nose gear collapse and fuselage damage, resulting in two sections separating. The pilots were incapacitated, and the aircraft landed off the runway, traveling across a ditch approximately 3000 feet from the threshold. No injuries were reported.A Conair Aviation Convair CV-580 turboprop conversion 340-32 experienced a loss of directional control and subsequent runway excursion during landing at Manning Airport (CFX4), Manning, Alberta. The aircraft sustained significant damage, including nose gear collapse and fuselage damage, resulting in two sections separating. The pilots were incapacitated, and the aircraft landed off the runway, traveling across a ditch approximately 3000 feet from the threshold. No injuries were reported.