more the lead). Generally, the lead is 10 percent of the climb rate. For example, if your climb rate is 500 feet per minute, you should lead the level-off by 50 feet.  To begin the level-off, apply forward cyclic to adjust and maintain a level flight attitude, which is slightly nose low. You should maintain climb power until the airspeed approaches the desired cruising airspeed, then lower the collective to obtain cruising power and adjust the throttle to obtain and maintain cruising r.p.m. Throughout the level-off, maintain longitudinal trim and heading with the antitorque pedals. Ground reference maneuvers are training exercises flown to help you develop a division of attention between the flight path and ground references, while controlling the helicopter and watching for other air- craft in the vicinity. Prior to each maneuver, a clearing turn should be accomplished to ensure the practice area is free of conflicting traffic. The rectangular course is a training maneuver in which the ground track of the helicopter is equidistant from all sides of a selected rectangular area on the ground. While performing the maneuver, the altitude and air- speed should be held constant. The rectangular course helps you to develop a recognition of a drift toward or away from a line parallel to the intended ground track. This is helpful in recognizing drift toward or from an airport runway during the various legs of the airport traffic pattern. A normal descent is a maneuver in which the helicop- ter loses altitude at a controlled rate in a controlled attitude. To establish a normal descent from straight-and-level flight at cruising airspeed, lower the collective to obtain proper power, adjust the throttle to maintain r.p.m., and increase right antitorque pedal pressure to maintain heading in a counterclockwise rotor system, or left pedal pressure in a clockwise system. If cruising  airspeed is the same as, or slightly above descending air- speed, simultaneously apply the necessary cyclic  pressure to obtain the approximate descending attitude. If cruising speed is well above descending airspeed, you can maintain a level flight attitude until the airspeed approaches the descending airspeed, then lower the nose to the descending attitude. Throughout the maneu- ver, maintain descending attitude and airspeed with the cyclic; descending power and r.p.m. with the collective and throttle; and heading with the antitorque pedals. For this maneuver, pick a square or rectangular field, or an area bounded on four sides by section lines or roads, where the sides are approximately a mile in length. The area selected should be well away from other air traffic. Fly the maneuver approximately 600 to 1,000 feet above the ground, which is the altitude usually required for an airport traffic pattern. You should fly the helicopter parallel to and at a uniform distance, about one-fourth to one-half mile, from the field boundaries, not above the boundaries. For best results, position your flight path outside the field boundaries just far enough away that they may be easily observed from either pilot seat by looking out the side of the helicopter. If an attempt is made to fly directly above the edges of the field, you will have no usable reference points to start and complete the turns. In addition, the closer the track of the helicop- ter is to the field boundaries, the steeper the bank necessary at the turning points. Also, you should be able to see the edges of the selected field while seated in a normal position and looking out the side of the helicopter during either a left-hand or right-hand course. The distance of the ground track from the edges of the field should be the same regardless of whether the course is flown to the left or right. All turns should be started when your helicopter is abeam the corners of the field boundaries. The bank nor- mally should not exceed 30°. To level off from the descent, lead the desired altitude by approximately 10 percent of the rate of descent. For exam- ple, a 500 feet per minute rate of descent would require a 50 foot lead. At this point, increase the collective to obtain cruising power, adjust the throttle to maintain r.p.m., and increase left antitorque pedal pressure to maintain heading (right pedal pressure in a clockwise rotor system). Adjust the cyclic to obtain cruising airspeed and a level flight atti- tude as the desired altitude is reached. Although the rectangular course may be entered from any direction, this discussion assumes entry on a  9-14 1. Failure to maintain constant angle of decent dur- ing training. COMMON ERRORS TECHNIQUE NORMAL DESCENT RECTANGULAR COURSE COMMON ERRORS GROUND REFERENCE MANEUVERS 2. Failure to lead the level-off sufficiently, which results in recovery below the desired altitude. 3. Failure to adjust antitorque pedal pressures for changes in power. 1. Failure to maintain proper power and airspeed. 2. Holding too much or too little antitorque pedal. 3. In the level-off, decreasing power before lower- ing the nose to cruising attitude.