MAXIMUM PERFORMANCE TAKEOFF TECHNIQUE COMMON ERRORS RUNNING/ROLLING TAKEOFF 10-2 Figure 10-1. Maximum performance takeoff. For wheeled helicopters, a rolling takeoff is sometimes used to minimize the downwash created during a take- off from a hover.  To accomplish a safe running or rolling takeoff, the sur- face area must be of sufficient length and smoothness, and there cannot be any barriers in the flight path to interfere with a shallow climb.  A running takeoff in a skid-type helicopter or a rolling takeoff in a wheeled helicopter is sometimes used when conditions of load and/or density altitude prevent a sus- tained hover at normal hovering altitude. However, you should not attempt this maneuver if you do not have sufficient power to hover, at least momentarily. If the helicopter cannot be hovered, its performance is unpre- dictable. If the helicopter cannot be raised off the  surface at all, sufficient power might not be available to safely accomplish the maneuver. If you cannot momentarily hover the helicopter, you must wait for conditions to improve or off-load some of the weight. Before attempting a maximum performance takeoff, bring the helicopter to a hover, and determine the excess power available by noting the difference between the power available and that required to hover. You should also perform a balance and flight control check and note the position of the cyclic. Then position the helicopter into the wind and return the helicopter to the surface. Normally, this maneuver is initiated from the surface. After checking the area for obstacles and other aircraft, select reference points along the takeoff The angle of climb for a maximum performance take- off depends on existing conditions. The more critical the conditions, such as high density altitudes, calm winds, and high gross weights, the shallower the angle of climb. In light or no wind conditions, it might be necessary to operate in the crosshatched or shaded areas of the height/velocity diagram during the begin- ning of this maneuver. Therefore, be aware of the  calculated risk when operating in these areas. An engine failure at a low altitude and airspeed could place the helicopter in a dangerous position, requiring a high degree of skill in making a safe autorotative landing. To safely accomplish this type of takeoff, there must be enough power to hover, in order to prevent the helicop- ter from sinking back to the surface after becoming  airborne. This hover power check can be used to deter- mine if there is sufficient power available to accomplish this maneuver. A maximum performance takeoff is used to climb at a steep angle to clear barriers in the flight path. It can be used when taking off from small areas surrounded by high obstacles. Before attempting a maximum  performance takeoff, you must know thoroughly the capabilities and limitations of your equipment. You must also consider the wind velocity, temperature, alti- tude, gross weight, center-of-gravity location, and other factors affecting your technique and the perform- ance of the helicopter.  path to maintain ground track. You should also consider alternate routes in case you are not able to complete the maneuver. [Figure 10-1] Begin the takeoff by getting the helicopter light on the skids (position 1). Pause and neutralize all aircraft move- ment. Slowly increase the collective and position the cyclic so as to break ground in a 40 knot attitude. This is approximately the same attitude as when the helicopter is light on the skids. Continue to slowly increase the collec- tive until the maximum power available is reached. This large collective movement requires a substantial increase in pedal pressure to maintain heading (position 2). Use the cyclic, as necessary, to control movement toward the desired flight path and, therefore, climb angle during the maneuver (position 3). Maintain rotor r.p.m. at its maxi- mum, and do not allow it to decrease since you would probably have to lower the collective to regain it. Maintain these inputs until the helicopter clears the obstacle, or until reaching 50 feet for demonstration purposes (position 4). Then, establish a normal climb attitude and reduce power (position 5). As in any maximum performance maneuver, the techniques you use affect the actual results. Smooth, coordinated inputs coupled with precise control allow the helicopter to attain its maximum performance. 5. Failure to resume normal climb power and air- speed after clearing the obstacle. 4. Abrupt control movements. 3. Failure to maintain maximum permissible r.p.m. 2. Nose too low initially, causing horizontal flight rather than more vertical flight. 1. Failure to consider performance data, including height/velocity diagram.