S-Turns

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OBJECTIVE: To develop the pilot's ability to compensate for drift during turns, orient the flightpath with ground references, and divide the pilot's attention

ELEMENTS:

A. How to select a suitable altitude. B. How to select a suitable ground reference line with suitable emergency landing areas. C. Orientation, division of attention, and planning. D. Configuration and airspeed prior to entry. E. Entry technique. F. Wind drifts correction. G. Tracking of semicircles of equal radii on either side of the selected ground reference line. H. How to maintain desired altitude and airspeed. I. Turn reversal over the ground reference line. J. Coordination of flight controls.

ASSOCIATED MANEUVERS:

SCHEDULE: Pre-flight instruction: 10 Minutes Travel to training area: 10 Minutes Instructor Demonstration: 10 Minutes Student Practice: 20 Minutes Return from practice area: 10 minutes Post-flight Review: 10 Minutes Total Time: 1:10

EQUIPMENT: Functional aircraft.

INSTRUCTOR’S ACTIONS: A. Conduct preflight training on the elements of S Turns. B. Demonstrate S Turns F. Conduct post flight briefing.

STUDENT’S ACTIONS: A. Ask questions, review homework. B. Perform preflight. C. Observe demonstrations. D. Perform IAW PTS.

COMPLETION STANDARDS: Student performs S Turns IAW the PTS.

COMMON ERRORS: A. Faulty entry technique. B. Poor planning, orientation, or division of attention. C. Uncoordinated flight control application. D. Improper correction for wind drift. E. A non-symmetrical ground track. F. Failure to maintain selected altitude or airspeed. G. Selection of a ground reference line where this is no suitable emergency landing area within gliding distance.

Introduction: Every time we turn the airplane we make adjustments for the wind. This is especially true for flying in the traffic pattern. In the pattern we want to maintain the same relative distance to the runway until we turn final. S-turns show us the effect that wind has on an airplane and how we compensate for that while in a turn. Basically we will do this about 1000 feet agl. We will use a road or some other clearly identifiable straight line on the ground. We will fly across the road with the wind, then turn back toward the road, level of in time to cross the road and then turn again towards the road. This makes an “S” pattern across the road. The object here is to maintain perfect half circles on either side of the road and to be wings level ONLY long enough to cross the road. You maintain your relative position by adjusting your angle of bank and hence your rate of turn. You need to keep your altitude and airspeed where you start the maneuver.

A. Lesson Requirements:

1. Task: Perform a S-turn.

2. Condition: Given a functional aircraft.

3. Standard: IAW the PTS.

a. Exhibits knowledge of the elements related to S-turns.

b. Determines the wind direction and speed.

c. Selects the reference line with an emergency landing area within gliding distance.

d. Plans the maneuver so as to enter at 600 to 1,000 feet (180 to 300 meters) AGL, perpendicular to the selected reference line, downwind, with the first series of turns to the left.

e. Applies adequate wind-drift correction to track a constant radius half-circle on each side of the selected reference line.

f. Divides attention between airplane control and the ground track and maintains coordinated flight.

g. Reverses course, as directed by the examiner, and exits at the point of entry at the same altitude and airspeed at which the maneuver was started.

h. Maintains altitude +- 100 feet (30 m) and airspeed +- 10 knots.

B. ELO 1: Understand the effects of wind on a flying airplane.

1. The air is more like the ocean than a solid mass. As the wind blows it will tend to push an airplane in the direction of airflow. This is just like an boat in a river as it flows in the direction of the stream. Pilots compensate for this by adjusting the crab angle in straight slight, and by adjusting the angle of bank in turns.

2. How do winds affect groundspeed? Moving downwind (with the wind) causes the airplane to have an increase in groundspeed. Moving upwind (against the wind) causes the airplane to have a decrease in groundspeed. In both cases the airspeed indicator may read the same.

3. How do winds affect the angle of bank and rate of turn? When traveling on the downwind side of the turn the airplane tends to increase speed and a greater rate of turn must be used to compensate for the increased airspeed. On the upwind side of the turn, the bank will be shallower because the airplane is moving slower.

4. Student Check:

What portion of the S-turn will have a steeper turn? _______ Where do you enter the S-turn relative to the wind? ______

C. ELO 2: Identify common errors in the S-turn.

1. Faulty entry technique.

2. Poor planning, orientation, or division of attention.

3. Uncoordinated flight control application.

4. Improper correction for wind drift.

5. A non-symmetrical ground track.

6. Failure to maintain selected altitude or airspeed.

7. Selection of a ground reference line where this is no suitable emergency landing area within gliding distance.

8. Student Check:

i. What is Vx on this aircraft? ________ ii. What is Vy on this aircraft? ________

D. ELO 3: Perform a S-turn.

1. Pick an appropriate entry altitude (700-1000 ft agl works well). NO LOWER than 500 feet agl.

2. Pick your reference line.

3. Enter the maneuver WITH the wind and perpendicular to the line. Once you cross the reference line, start a 180 degree turn.

4. Maintain the turn until you come about 180 degrees. This should be just as you are about to cross your reference line.

5. Once you cross the reference line begin a turn in the other direction to complete the S.

6. Maintain the turn until you come about 180 degrees. This should be just as you are about to cross your reference line.

7. Continue the maneuver until told to stop.