Climbing is a segment of flight from the flight departure until reaching the desired altitude. The most important variables that are observed during the climb are: rate of climb, angle of climb, climb time and fuel consumption of the aircraft. Climb performance is strongly affected by the mass of the aircraft, the available engine power and meteorological conditions. Different regimes of climb can be determined by combining the values of previously mentioned factors. Within this study the differences between theoretical and actual speed of ascent, the angle of climb, climbing time and fuel consumption have been analyzed for the aircraft Dash 8 Q400.