Settling with power. a. A flight condition when collective inputs are ineffective in arresting a rate of descent due to an unsteady airflow about the rotor system. (1) Induced velocity during hovering flight. The magnitude of the induced flow velocity is greatest at the tips of the blades and decreases toward the hub. (2) Variations in induced flow velocity prior to vortex ring state. (a) If the helicopter begins to settle, an upward velocity will be superimposed on the induced flow velocity. (b) Since the upflow is uniform across the rotor, its influence will first be felt at the hub. 3) Vortex ring state. (a) If the helicopter continues to descend with insufficient airspeed, it will enter the vortex ring state. (b) There is a portion of positive thrust on the outer portion of the rotor and an area of negative thrust at the center. (c) If not corrected, an extremely high rate of descent can develop. b. Necessary conditions. The following combination of conditions are likely to cause settling with power. (1) A vertical or near vertical descent at a high rate of speed. The actual rate would depend on the following variables: (a) Gross weight. (b) Rotor RPM. (c) Density altitude. (2) The rotor system must be using all or some of the available engine power. (3) Loss of translational lift (airspeeds near zero). c. Conductive flight situations. (1) Attempting to hover out-of-ground-effect at or above the hover ceiling of the aircraft. (2) Attempting to hover out-of-ground-effect within the hovering ceiling of the aircraft without maintaining precise altitude control. (3) Steep power approaches in which the airspeed is permitted to drop nearly to zero. d. Symptoms. (1) High rate of descent (minimum of 300 feet per minute). (2) High power consumption. (3) Loss of collective pitch effectiveness. (4) Vibrations. e. Corrective actions. (1) Establish directional flight. (2) Lower collective pitch. (3) Increase RPM if decayed. (4) Apply right pedal.
Posted on: Tue, 25 Jun 2013 08:12:48 +0000
Recently Viewed Topics
© 2015