Steep Spiral

Steep Spiral

Description

Objective: To improve pilot techniques for airspeed control, wind drift control, planning, orientation, and division of attention.

Here is Harry's YouTube video showing/explaining how to do this maneuver:



Before Flight: This maneuver is also valuable for remaining over selected spot in preparation for landing, especially emergencies. Review appropriate aircraft performance information. Steepest bank will be no more that 60°. Altitude must be such that will allow three 360° turns. Maneuver should not continue below 1000′ AGL. Throttle should be advanced occasionally to prevent excessive engine cooling or spark plug fouling. Constant airspeed should be held throughout the maneuver.

During Flight: Point on ground should be selected prior to entry. Throttle should be closed and a constant-radius circle should be drawn around the selected ground point. Roll-out should be made on a selected heading or toward a selected reference point.

Completion Standards: The lesson is complete when the student demonstrates knowledge through a written or oral exam and is able to perform steep spiral descents to the satisfaction of the instructor and in accordance with the current Practical Test Standards for the student’s stage of training.

Common errors in the performance of steep spirals are:
• Failure to adequately clear the area.
• Failure to maintain constant airspeed.
• Poor coordination, resulting in skidding and/or slipping.
• Inadequate wind drift correction.
• Failure to coordinate the controls so that no increase/decrease in speed results when straight glide is resumed.
• Failure to scan for other traffic.
• Failure to maintain orientation.

The steep spiral can also be used for an emergency descent. Click on the emergency descent link below for some thoughts on the emergency descent.


CommercialPilot, ComLP, CFILP, PvtLP
Detailed Information
Detailed Description
The objective of this maneuver is to improve pilot techniques for airspeed control, wind drift control, planning, orientation, and division of attention. The steep spiral is not only a valuable flight training maneuver, but it has practical application in providing a procedure for dissipating altitude while remaining over a selected spot in preparation for landing, especially for emergency forced landings. A steep spiral is a constant gliding turn, during which a constant radius around a point on the ground is maintained similar to the maneuver, turns around a point. The radius should be such that the steepest bank will not exceed 60°. Sufficient altitude must be obtained before starting this maneuver so that the spiral may be continued through a series of at least three 360° turns. The maneuver should not be continued below 1,000 feet above the surface unless performing an emergency landing in conjunction with the spiral. Operating the engine at idle speed for a prolonged period during the glide may result in excessive engine cooling or spark plug fouling. The engine should be cleared periodically by briefly advancing the throttle to normal cruise power, while adjusting the pitch attitude to maintain a constant airspeed. Preferably, this should be done while headed into the wind to minimize any variation in groundspeed and radius of turn. After the throttle is closed and gliding speed is established, a gliding spiral should be started and a turn of constant radius maintained around the selected spot on the ground. This will require correction for wind drift by steepening the bank on downwind headings and shallowing the bank on upwind headings, just as in the maneuver, turns around a point. During the descending spiral, the pilot must judge the direction and speed of the wind at different altitudes and make appropriate changes in the angle of bank to maintain a uniform radius. A constant airspeed should also be maintained throughout the maneuver. Failure to hold the airspeed constant will cause the radius of turn and necessary angle of bank to vary excessively. On the downwind side of the maneuver, the steeper the bank angle, the lower the pitch attitude must be to maintain a given airspeed. Conversely, on the upwind side, as the bank angle becomes shallower, the pitch attitude must be raised to maintain the proper airspeed. This is necessary because the airspeed tends to change as the bank is changed from shallow to steep to shallow. During practice of the maneuver, the pilot should execute three turns and roll out toward a definite object or on a specific heading. During the rollout, smoothness is essential, and the use of controls must be so coordinated that no increase or decrease of speed results when the straight glide is resumed.
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