the particular helicopter being flown. Normally, in heli- copters with low climb rates, 500 f.p.m. is appropriate, in helicopters capable of high climb rates, use a rate of 1,000 f.p.m. To enter a constant rate climb, increase power to the approximate setting for the desired rate. As power is applied, the airspeed indicator is primary for pitch until the vertical speed approaches the desired rate. At this time, the vertical speed indicator becomes primary for pitch. Change pitch attitude by reference to the attitude indicator to maintain the desired vertical speed. When the VSI becomes primary for pitch, the airspeed indica- tor becomes primary for power. Primary and supporting instruments for a stabilized constant rate climb are illus- trated in figure 12-19. Adjust power to maintain desired airspeed. Pitch attitude and power corrections should be closely coordinated. To illustrate this, if the vertical speed is correct but the airspeed is low, add power. As power is increased, it may be necessary to lower the pitch attitude slightly to avoid increasing the vertical rate. Adjust the pitch attitude smoothly to avoid over- controlling. Small power corrections usually will be sufficient to bring the airspeed back to the desired indi- cation.  The leveloff from a constant airspeed climb must be started before reaching the desired altitude. Although the amount of lead varies with the helicopter being flown and your piloting technique, the most important factor is vertical speed. As a rule of thumb, use 10 percent of the vertical velocity as your lead point. For example, if the rate of climb is 500 f.p.m., initiate the leveloff approxi- mately 50 feet before the desired altitude. When the proper lead altitude is reached, the altimeter becomes primary for pitch. Adjust the pitch attitude to the level flight attitude for that airspeed. Cross-check the altime- ter and VSI to determine when level flight has been attained at the desired altitude. To level off at cruise air- speed, if this speed is higher than climb airspeed, leave the power at the climb power setting until the airspeed approaches cruise airspeed, then reduce it to the cruise power setting. The leveloff from a constant rate climb is accomplished in the same manner as the leveloff from a constant air- speed climb.  A descent may be performed at any normal airspeed the helicopter is capable of, but the airspeed must be deter- mined prior to entry. The technique is determined by whether you want to perform a constant airspeed or a constant rate descent. If your airspeed is higher than descending airspeed, and you wish to make a constant airspeed descent at the descending airspeed, reduce power to the descending power setting and maintain a constant altitude using cyclic pitch control. When you approach the descend- ing airspeed, the airspeed indicator becomes primary for pitch, and the torque meter is primary for power. As you hold the airspeed constant, the helicopter begins to descend. For a constant rate descent, reduce the power ENTRY LEVELOFF  STRAIGHT DESCENTS (CONSTANT AIRSPEED AND CONSTANT RATE) 40 50 60 70 80 90 100 110 120 0 10 20 30 TORQUE PERCENT GLYPH<.notdef> SupportingGLYPH<.notdef> PowerGLYPH<.notdef> GLYPH<.notdef> Supporting Pitc hGLYPH<.notdef> and Bank Primary Bank Primary Power Primary Pitch Supporting Bank Figure 12-19. Flight instrument indications in a stabilized constant rate climb. 12-14