Theory and Practice of Aircraft Performance

CHAPTER 12Climb and Descent Performance

12.1 Overview

The last chapter dealt with takeoff and landing performances of aircraft. The next segment of a mission after takeoff to 35 ft is to climb away from the first segment takeoff procedure to cruise altitude. At the end of cruise, the aircraft descends to land. Climb and descent segments are carried out in the vertical plane of the aircraft. Since the equations of motions for climb and descent are similar, they are considered together in this chapter. Here we deal comprehensively with all aspects of the climb and descent segments of a mission, including both the point and integrated climb and descent performances. The values for distance covered, time taken and fuel consumed are required to obtain aircraft payload range. A methodology to establish a commercial aircraft climb schedule is shown.

Aircraft climb can be carried out in many ways depending on the flight planning. Civil and military climb schedules differ on account of differences in mission requirements. In civil applications, the aircraft climbs in a specified speed schedule for piloting ease, economy, and to clear any obstacle in the flight path. Military climb schedules demand faster climb rates and are more frequently required to clear an obstacle in low‐level operations. Physically, descent can be seen as the opposite to climb. Civil aircraft descent is with zero or partial thrust setting and is restricted by the cabin pressurization schedule. Military aircraft ...