SECTION VI. TAKEOFF

TM 1-1520-240-10 7-6-1 SECTION VI. TAKEOFF 7-6-1. Description. The takeoff chart, figure 7-6-1, defines distances re- quired to clear obstacles of 50 feet, 100 feet, 150 feet, and 200 feet based upon maximum hover height capabil- ity and true airspeed. The procedure for takeoff is the level flight acceleration technique. NOTE The maximum hover heights shown are indica- tive of helicopter performance capability and do not imply that this hover height must be main- tained through takeoff. 7-6-2. Use of Chart. The primary use of the chart is illustrated by the exam- ples. a. To determine the distance required to clear an obstacle, it is necessary to know maximum hover height (hover capability), obstacle height, and climbout true airspeed. Calculation of maximum hover height is described in Section V, Hover. Enter the chart for the required obstacle height, move right to desired true climbout airspeed, then down and read distance required to clear obstacle. b. A hover check should be made prior to takeoff to verify hover capability. If winds are present, hover capability will be greater than predicted since the hover chart is based on calm wind conditions. 7-6-3. Conditions. a. The takeoff chart is based on calm wind conditions. Since the surface wind velocity and direction cannot be accurately predicted, all takeoff planning should be based on calm air conditions. Takeoff into the wind will improve takeoff performance. CAUTION A tailwind during takeoff and climbout will increase the distance for obstacle clearance and may prevent a successful takeoff. b. Takeoff performance data are based on the use of maximum torque available at 100% RRPM.