r.p.m. with the throttle. Throughout the maneuver, maintain a desired groundspeed and ground track with the cyclic, a constant heading with antitorque pedals, the desired altitude with the collective, and proper operating r.p.m. with the throttle. To stop the forward movement, apply aft cyclic pressure to reduce forward speed. Simultaneously lower the col- lective to initiate a descent to hover altitude. As  forward motion stops, return the cyclic to the neutral posi- tion to prevent rearward movement. When at the proper hover altitude, increase the collective as necessary. A "hover taxi" is used when operating below 25 feet AGL. [Figure 9-5] Since hover taxi is just like forward, sideward, or rearward hovering flight, the technique to perform it will not be presented here. An "air taxi" is preferred when movements require greater distances within an airport or heliport bound- ary [Figure 9-6] In this case, you basically fly to your new location; however you are expected to remain below 100 feet AGL, and to avoid overflight of other aircraft, vehicles, and personnel.  A "surface taxi," for those helicopters with wheels, is used whenever you wish to minimize the effects of rotor downwash. [Figure 9-7] Before starting, determine the appropriate airspeed and altitude combination to remain out of the cross-hatched or shaded areas of the height-velocity diagram. Additionally be aware of crosswind conditions that could lead to loss of tail rotor ef fectiveness. Pick out two references directly in front of the helicopter for the ground path desired. These reference points should be kept in line throughout the maneuver. Begin the maneuver from a normal hovering altitude by applying forward pressure on the cyclic. As move- ment begins, attain the desired airspeed with the cyclic. Control the desired altitude with the collective, and The helicopter should be in a stationary position on the surface with the collective full down and the r.p.m. the same as that used for a hover. This r.p.m. should be maintained throughout the maneuver. Then, move the cyclic slightly forward and apply gradual upward pres- sure on the collective to move the helicopter forward 9-9 TECHNIQUE TECHNIQUE SURFACE TAXI AIR TAXI COMMON ERRORS HOVER TAXI 1. Erratic movement of the cyclic, resulting in improper airspeed control and erratic movement over the surface. 2 . Failure to use antitorque pedals properly, result- ing in excessive heading changes. 3. Failure to maintain desired altitude. 4. Failure to maintain proper r.p.m. 5. Overflying parked aircraft causing possible dam- age from rotor downwash. 6. Flying in the cross-hatched or shaded area of the height-velocity diagram. 7. Flying in a crosswind that could lead to loss of tail rotor effectiveness. Figure 9-7. Surface taxi. Figure 9-6. Air taxi. Figure 9-5. Hover taxi. Hover TaxiGLYPH<.notdef> (25 Feet or Less) Poor Surface Conditions or Skid Type Helicopters Air TaxiGLYPH<.notdef> (100 Feet or Less) Faster Travel Surface Taxi Less Rotor Downwash