Category A: less than 169 km/h (91 kt) indicated airspeed (IAS) Category B: 169 km/h (91 kt) or more but less than 224 km/h (121 kt) IAS. Category C: 224 km/h (121 kt) or more but less than 261 km/h (141 kt) IAS. Category D: 261 km/h (141 kt) or more but less than 307 km/h (166 kt) IAS.