An aerial vehicle that is operable to fly, the aerial vehicle having at least a first and second subsystem (250a,b) that are operably connected, wherein the first subsystem comprises a first flight module, first one or more effectors that are selectively operable to generate a first force sufficient to cause the aerial vehicle to fly; and the second subsystem comprises a second flight module, second one or more effectors that are selectively operable to generate a second force sufficient to cause the aerial vehicle to fly; such that the first or second subsystem (250a,b) can be selectively used to fly the aerial vehicle not relying on the one or more effectors of the other subsystem (250a,b) characterized in that, the first flight module comprises, a first switch; a first coordination unit for controlling the first switch; a first normal operation control unit that is operable to generate control signals for operating the first and second one or more effectors; a first emergency control unit that is operable to generate control signals for operating the first one or more effectors, wherein the first switch is configured such that it can be selectively switched by the first coordination unit between a first position where it passes the control signals generated by the first normal operation control unit to the first one or more effectors, a second position where it passes the control signals generated by the first emergency control unit to the first one or more effectors; the second flight module comprises, a second switch; a second coordination unit for controlling the second switch; a second emergency control unit that is operable to generate control signals for operating the second one or more effectors, and wherein the second switch is configured such that it can be selectively switched by the second coordination unit between a first position where it passes the control signals generated by the first normal operation control unit to the second one or more effectors, a second position where it passes the control signals generated by the second emergency control unit to the second one or more effectors. wherein the first subsystem comprises a first flight module, first one or more effectors that are selectively operable to generate a first force sufficient to cause the aerial vehicle to fly; and the second subsystem comprises a second flight module, second one or more effectors that are selectively operable to generate a second force sufficient to cause the aerial vehicle to fly; such that the first or second subsystem (250a,b) can be selectively used to fly the aerial vehicle not relying on the one or more effectors of the other subsystem (250a,b) characterized in that, the first flight module comprises, a first switch; a first coordination unit for controlling the first switch; a first normal operation control unit that is operable to generate control signals for operating the first and second one or more effectors; a first emergency control unit that is operable to generate control signals for operating the first one or more effectors, wherein the first switch is configured such that it can be selectively switched by the first coordination unit between a first position where it passes the control signals generated by the first normal operation control unit to the first one or more effectors, a second position where it passes the control signals generated by the first emergency control unit to the first one or more effectors; the second flight module comprises, a second switch; a second coordination unit for controlling the second switch; a second emergency control unit that is operable to generate control signals for operating the second one or more effectors, and wherein the second switch is configured such that it can be selectively switched by the second coordination unit between a first position where it passes the control signals generated by the first normal operation control unit to the second one or more effectors, a second position where it passes the control signals generated by the second emergency control unit to the second one or more effectors.