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Rectangular Course

Introduction:

  • The rectangular course maneuver simulates the airport traffic pattern, demonstrating the effect of wind on an aircraft [Figure 1]
  • The maneuver assists the student pilot in perfecting:
    • Practical application of the turn
    • The division of attention between the flightpath, ground objects, and the handling of the airplane
    • The timing of the start of a turn so that the turn will be fully established at a definite point over the ground
    • The timing of the recovery from a turn so that a definite ground track will be maintained
    • The establishing of a ground track and the determination of the appropriate "crab" angle

Rectangular Course Procedure:

WARNING:
All procedures here are GENERALIZED for learning.
Fly the maneuver in accordance with the Pilot Operating Handbook (POH)
and/or current Standard Operating Procedures (SOPs)


  1. Note wind direction and strength, if able
    • Important for finding the downwind and anticipating ground speed
    • Can be determined by trees, water, flags, etc...
  2. Perform clearing turns looking for traffic and ground obstructions
  3. Pick a reference rectangle in an area where an emergency landing can be made if necessary
    • Fields or perpendicular roads are best as they provide reference lines
    • Distances should be about 1 mile in length and maintained at the same distance throughout the maneuver
  4. Establish and maintain downwind speed and 1,000' AGL (simulating traffic pattern) throughout the maneuver maintaining 1/4th to 1/2 mile of lateral distance from the rectangular edges
  5. Enter the maneuver on a 45° mid-field downwind
    • Ground speed will increase as you enter the pattern
  6. Turn base at boundary:
    • AoB: Steep AoB, not to exceed 45°, transitioning to medium bank as the turn progresses
    • GS: Decrease, due to lost tailwind
    • Degrees: Turn greater than 90°, to compensate for wind, so as you roll out you have established a crab
  7. Turn upwind at boundary:
    • AoB: Medium AoB, transitioning shallow as the turn progresses
    • GS: Decrease, you are now flying directly into the wind
    • Degrees: Turn less than 90°, due to the crab already set prior to your turn
  8. Turn crosswind at boundary:
    • AoB: Shallow AoB, transitioning to medium as the turn progresses
    • GS: Increase, due to the loss of the complete headwind component
    • Degrees: Turn less than 90° to allow for wind correction
  9. Turn downwind at boundary:
    • AoB: Medium AoB transitioning to a much steeper AoB than earlier, not to exceed 45°
    • GS: Increase, due to the increasing tailwind
    • Degrees: Turn more than 90°
  10. Depart the maneuver on a 45° mid-field downwind
  11. Upon completion of the maneuver, resume normal cruise speed
    • Trim as necessary
  12. Complete cruise checklist

Rectangular Course
Airplane Flying Handbook, Rectangular Course

Notes:

  • It is unusual to find a situation where the wind is blowing exactly parallel to the field boundaries so slight wind corrections on all legs may be required
  • It is important to anticipate the turns to correct for ground speed, drift, angle of bank (AoB), and turning radius
  • When the wind is behind the airplane, the turn requires a larger AoB due to the turn radius/rate and vice versa
    • Because of this, you will need to anticipate your turn at different points around the box pattern
    • The higher the ground speed, the earlier you must anticipate the turn
  • Altitude and airspeed should be held constant
  • Requires utilization of ground track with wind forming a "crab" angle to maintain an equidistant track from all sides of the rectangle
    • Approximately 1/4 to 1/2 mile away
    • For a Cessna, this will be when the edge of the rectangle bisects the wing strut
    • The closer you fly, the steeper the turns will have to be, the farther, the shallower
  • Establish crab angles as necessary to maintain a uniform distance from the area boundaries for each leg of the maneuver

Common Errors:

  • Failure to adequately clear the area
  • Failure to establish proper altitude prior to entry (Typically entering the maneuver while descending)
  • Failure to establish appropriate wind correction angle, resulting in drift
  • Gaining or losing altitude
  • Poor coordination (Typically skidding in turns from a downwind heading and slipping in turns from an upwind heading)
  • Abrupt control usage
  • Inability to adequately divide attention between airplane control and maintaining ground track
  • Improper timing to beginning and recovering from turns
  • Inadequate visual lookout for other aircraft

Airman Certification Standards:

References: