Lesson 4f - Boxing the Wake

Lesson Objective

The lesson will allow the student to demonstrate manuvering behind the tow plane to different established positiong with regard to the tow plane's wake.  The maneuvers will be done in a fashion that is described by the FAA's Practical Test Standards: "Maneuvers the glider, while on tow, slightly outside the towplane’s wake in a rectangular, box-like pattern."

Regulatory Requirement

• Student Pilot §61.87(i)(12)
• Private Pilot Practical Test Standard IV(E)

Content

• Positions of the glider behind the towplane
• High and Low-tow positions (also see lesson plan 3a -- Hi-Low Tow Transition )
• Low-left, low-right, high-right, high-left

Procedures

There is no rush for this procedure. It is more important to take your time and get to all of the points on tow in a controlled and precise manner.  As a matter of convention and habit, Skyline Instructors and students usually combine the tasks of the Hi-Low Tow transition with the boxing of the wake with the following procedure:

• Before starting, as a courtesy, call the tow-plane on the radio, "4BY, this is 341 Kilo-Sierra, box the wake"
• Wait until the towplane has begun straight and level flight.
• Perform transition through the wake into low tow position, note visual reference when clear of wake.
• Proceed to low left tow position.  Hold briefly. 
• Proceed to high left tow position. Hold briefly.
• Proceed to high right tow position. Hold briefly.
• Proceed to low right tow position. Hold briefly.
• Proceed to center low tow position. Hold briefly.
• Return to normal high tow position, going back through the wake.

The maneuver can be in either a clockwise or counter-clockwise direction.  

NOTE: During the practical test the examiner may ask for you to perform the maneuvers of "High-Low Tow Transition" separately from "Boxing the Wake." In this circumstance, boxing the wake does NOT include transitioning through the wake at the beginning of the maneuver.  The candidate would maneuver around the wake without ever making contact with the tow plane's wake. 

If the box-wake maneuver is being performed separately from the Hi-Low Tow Transition, execute the following procedure. The following example is for clockwise direction. Either direction is possible. 

• Before starting, as a courtesy, call the towplane on the radio, and wait for it to attain straight and level flight. 
• Move from normal high tow position to the high-right tow position.  Pause for three seconds. 
• Move to low right tow position.  Pause for three seconds. 
• Move directly to low left tow position, without pausing at the low tow position.  Pause at the corner. 
• Proceed from low left tow position to high-left. Pause for three seconds. 
• Complete the maneuver by returning to the normal high tow position. 

Generally speaking, the low tow position behind the Pawnee is indicated when the horizontal stabilizer is lined up with the tow pilot's rear view mirror. Behind the Husky, the low tow position is achieved when the elevator is lined up with the wing. For both tow planes, the glider pilot knows that he has gone far enough to the side when the tail wheel and main wheels appear to line up. 

Completion Standards

The candidate must:

1. Exhibit knowledge of the elements related to boxing the wake (maneuvering around the wake).
2. Maneuver the glider, while on tow, slightly outside the towplane’s wake in a rectangular, box-like pattern.
3. Maintain proper control and coordination.

Prerequisite Study

• Glider Flying Handbook (2013), Chapter 7, page 7-12
• Soaring Safety Foundation -- "SSF PTS Boxing the Wake" (YouTube)

Hints

• You have reached low tow position when the horizontal stabilizer appears to cut through the rear-view mirror on the tow plane.
• You have gone out far enough to the side when the tail-wheel and the main wheel line up.
• A common error is to not maintain the horizontal position when moving from low-left to high-left and vice-versa.  Give a little bank to prevent getting pulled back to the center

Video Illustration

• Video of normal wake transition and boxing wake behind a Pawnee: Boxing the Wake 
• Video of normal wake transition and boxing wake behind the Husky: Boxing the Wake