A Pinnacle is an area from which the surface drops away steeply on all sides. A Ridgeline is a long area from which the surface drops away steeply on one or two sides, such as a bluff or precipice. The absence of obstacles does not necessarily lessen the difficulty of pinnacle or ridgeline operations.Updrafts, downdrafts, and turbulence, together with unsuitable terrain in which to make a forced landing, all contribute to present extreme hazards.
If you need to climb to a pinnacle or ridgeline, do it on the upwind side, when practable, to take advantage of any updrafts. The approach flight path should be parallel to the ridgeline and into the wind as much as possible.
Load, altitude, wind conditions, and terrain features determine the angle to use in the final part of an approach.
As a general rule, the greater the winds, the steeper the approach needs to be to avoind turbulent air and downdrafts. Groundspeed during the approach is more difficult to judge because visual references are farther away than during approaches over trees or flat terrain.
If a crosswind exists, remain clear of downdrafts on the leeward (downwind) side of the ridgeline. If the wind velocity makes the crosswind landing hazardous, you may be able to make a low, coordinated turn into the wind just prior to terminating the approach.
When making and approach to a pinnacle, avoid leeward trubulance and keep the helicopter within reach of a forced landing area for as long as possible.
On landing, take advantage of the long axis of the area when wind conditions permit. Touchdown should be made in the forward portion of the area. Always perform a stability check, prior to reducing rotor RPM, to ensure the landing gear is on firm terrain that can safely support the weight of the helicopter.
A pinnacle takeoff is a airspeed over altitude maneuver made from the ground or from a hover. Since pinnacles and ridgelines are generally higher than the immeadiate surrounding terrain, gaining airspeed on the takeoff is more important than gaining altitude. The higher the airspeed, the more rapid the departure from the slopes of the pinnacle. In addition to covering unfavorable terrain rapidly, a higher airspeed affords a more favorable glide angle and thus contributes to the chances of reaching a safe area in the event of a forced landing. If a suitable forced landing area is not available, a higher airspeed also permits a more effective flare prior to making a autorotative landing.
On takeoff, as the helicopter moves out of ground effect, maintain altitude and accelerate to normal climb airspeed. When normal climb speed is attained, establish a normal climb attitude. Never dive the helicopter down the slope after clearing the pinnacle.
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Page Last Updated on: Nov-06-2017