Common errors in the performance of level turns are:  direction. This causes an increase in total drag requiring an  increase in thrust (power) to balance the forces. An aircraft  can only sustain a climb angle when there is suffi cient thrust  to offset increased drag; therefore, climb is limited by the  thrust available.  [Figure 6-13] Instruction in level turns should begin with changing attitude  from level to bank, bank to level, and so on with a slight pause  at the termination of each phase. This pause allows the WSC  to free itself from the effects of any misuse of the controls  and ensures a correct start for the next turn. During these  exercises, the idea of control forces, rather than movement,  should be emphasized by pointing out the resistance of the  controls to varying forces applied to them.  Like other maneuvers, climbs should be performed using  outside visual references and flight instruments. It is  important that the pilot know the engine power settings  and pitch attitudes that produce the following conditions  of climb:  When an aircraft enters a climb, it changes its fl ightpath  from level flight to an inclined plane or climb attitude. As  discussed in chapter 2, weight in a climb no longer acts in a  direction perpendicular to the flightpath. It acts in a rearward  Descending Ascending Declined Plane Flight Path Inclined Plane Flight Path Figure 6-13. When a WSC aircraft stabilizes in a descent or a climb, the flightpath is a declined or inclined plane.  •  Failure to adequately clear the area before beginning  the turn.  •  Attempting to sit up straight, in relation to the ground,  during a turn, rather than riding with the aircraft. •  Failure to maintain a constant bank angle during the  turn. • Gaining proficiency in turns in only one direction.  •  Failure to coordinate the angle of attack to maintain  the proper airspeed. •  Failure to coordinate the use of throttle to maintain  level fl ight. •  Altitude gain/loss during the turn.  •   Normal climb—performed at an airspeed recommended  by the aircraft manufacturer. Normal climb speed is  generally the WSC best rate of climb (V$_{Y}$) speed as  discussed below. Faster airspeeds should be used for  climbing in turbulent air.  •   Best rate of climb (V$_{Y}$)—the airspeed at which an  aircraft will gain the greatest amount of altitude in a  given unit of time (maximum rate of climb in feet per  minute (fpm)). The V$_{Y}$ made at full allowable power  is a maximum climb. This is the most effi cient speed  because it has the best lift over drag ratio for the  aircraft. This speed is also the best glide ratio speed  used for going the greatest distance for the amount  of altitude, as discussed later in this chapter. Each  aircraft manufacturer is different but a good rule of  thumb is that the V$_{Y}$ is 1.3 times the stall speed. It  must be fully understood that attempts to obtain more  climb performance than the aircraft is capable of by  increasing pitch attitude results in a decrease in the   Climbs and Climbing Turns 6-12