Prior to conducting any Slope operations, you should be thouroughly familiar with the charistics of dynamic rollover and mast bumping, which are discussed in dynamic aerodynamics! The approach to a slpoe is similar to the approach to any other landing area. During slope operations, make allowances for wind, barriers, and forced landing sites in case of engine failure. Since the slope may constitute an obstruction to wind passage, you should anticipate turbulence and downdrafts.
You usually land a helicopter across the slope rather than with the slope. Landing with the helicopter facing down the slope (downhill) is not recommended because of the high probability of striking the tail rotor on the surface.
Please refer to the Figure below. At the termination of the approach, move the helicopter slowly towards the slope, being careful not to turn the tail upslope. Position the helicopter across the slope at a stabilized hover headed into the wind over the spot of intended landing (Frame 1). Downward pressure on the collective starts the helicopter descending. As the upslope skid or wheel touches the ground, hesitate momentarily in a level attitude, then apply lateral cyclic in the direction of the slope (Frame 2). This holds the skid against the slope while you continue lowering the downslope skid with the collective. As you lower collective, continue to move the cyclic towards the slope to maintain a fixed position (Frame 3). The slope must be shallow enough so you can hold the helicopter against it with the cyclic during the entire landing. A slope of 15 degrees is considered maximum for normal operation of most helicopters, However check the POH of the particular helicopter being flown for the manufacturer's recommended limitation.
You should be aware of any abnormal vibration or mast bumping, that signals maximum cyclic deflection. If this occurs, abandon the landing because the slope is too steep. In most helicopters with a counterclockwise rotor system, landings can be made on steeper slopes when you are holding the cyclic to the right. When landing on slopes using left cyclic, some cyclic input must be used to overcome translating tendancy. If wind is not a factor, you should consider the drifting tendancy when determining landing direction.
After the downslope skid is on the surface, reduce the collective to the full down position, and neutralize the cyclic and pedals (Frame 4). Normal operating RPM should be maintained until the full weight of the helicopter is on the landing gear. This ensures adequate RPM for immeadiate takeoff in case the helicopter starts sliding down the slope. Use antitorque pedals as necessary throughout the landing for heading control. Before reducing RPM, move the cyclic as necessary to check that the helicopter is firmly on the ground.
Failure to consider wind effects during the approach and landing.
Failure to maintain proper rotor RPM throughout the maneuver.
Turning the tail of the helicopter into the slope.
Lowering the downslope skid or wheel too rapidly.
Applying excessive cyclic control into the slope, causing mast bumping.
A slope takeoff is basically the reverse of a slope landing. Conditions that may be associated with the slope, such as turbulence and obstacles, must be considered during the takeoff. Planning should include suitable forced landing areas.
Please refer to the Figure below. Begin the takeoff by increasing RPM to the normal range with the collective full down. Then, move the cyclic towards the slope (Frame 1). Holding cyclic towards the slope causes the downslope skid or wheel to rise as you slowly raise the collective (Frame 2). as the skid or wheel comes up, move the cyclic towards the neutral position. If properly coordinated, the helicopter should attain a level atttude as the cyclic reaches the neutral position. At the same time, use antitorque pedal pressure to maintain heading and throttle to maintain RPM. With the helicopter level and cyclic centered, pause momentarily to verify everything is correct, and then gradually raise the collective to complete the liftoff (Frame 3).
After reaching a hover, take care not to avoid hitting the ground with the tail rotor. If an upslope wind exists, excute a crosswind takeoff and then make a turn into the wind after clearing the ground with the tail rotor.
SLOPE TAKEOFF
Technique
Common Errors
Failure to adjust cyclic control to keep the helicopter from sliding downslope.
Failure to maintain proper rotor RPM.
Holding excessive cyclic into the slope as the downslope skid or wheel is raised.
Turning the tail of the helicopter into the slope during takeoff.
Slopes can be tricky, the most important thing to remember is the limitation on your particular helicopter.
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Page Last Updated on: Nov-06-2017
