Crabbing Around A Point
A New Twist On An Old ManeuverEnter your turns around a point in the downwind direction...nah. Upwind direction...nah. Enter turns around a point in a crosswind direction on either the upwind side or the downwind side. Now you're talking!
Teaching primarily in gliders as I do forces some tight time constraints on performing ground reference maneuvers, because any time you are low enough to the ground for them to be meaningful, a landing is only a few minutes away. As a result, students need to get the maneuver right from the outset and thoroughly understand it before attempting to fly it. (As a side note, a turn around a point in a glider is really a descending spiral, but all the theory is the same and can be directly applied to performing the maneuver in a powered aircraft.)
The authors of the FAA's Flight Training Manual suggest that you enter a turn around a point in a downwind direction. The traditional reasoning is that you will have the fastest groundspeed and require the steepest bank angle during this portion of the maneuver. You must guess at the distance from the point, get into the steepest part of the turn immediately as you are passing the point, and then continually reduce the bank until you are heading upwind.
To paraphrase this process, first you guess at the distance from the point, then guess at the maximum angle of bank, put in the steep bank instantly, then guess at the amount to reduce the bank in order to cause the airplane to crab toward the point, and then guess at the crab angle needed to hold the radius. All this is nearly impossible for any but the most experienced pilots to do with acceptable results. It's so hard that this maneuver always reminds me of the old joke about the worker saying, "We pretend to work and they pretend to pay us." I submit that students pretend to do turns around a point and examiners pretend to accept them.
As the student maneuvers around the point, confusion sets in as to the quadrant that the airplane is in, causing great difficulty in achieving a constant radius. To set the proper angle, the student must change the bank and then wait for the position to change relative to the point, meaning the student is always a little behind the maneuver. Solution: Enter the turn on a crosswind leg!
Let me explain. I define turns around a point as a crabbing maneuver - as long as the crab angle is held perfectly, the outcome will be correct. At the precise moment the aircraft is traveling crosswind and is directly opposite the point, the perfect crab angle it is built right in. At this instant, the lateral axis of the airplane will point to a secondary point shifted from the actual point in a crosswind direction. This other point - let's call it point 2 - will be exactly the right place to keep the lateral axis of the airplane pointing all the way around the turn. Keeping the lateral axis on point 2 will automatically cause the pilot to always have the correct crab angle and cause the plane to carve a perfect circle around the original point.
Take a minute to compare the two methods of teaching and executing turns around a point.
Traditional method (entering the turn on downwind):
- Guess at the radius of the turn.
- Guess at the necessary bank angle.
- Guess at the proper crab angle.
My method (entering the turn on either crosswind):
- Guess at the radius.
- The crab angle is already fixed all the way around.
- Bank to keep the wing from falling behind or ahead of point 2.
Even with an excessively large radius, the principles still apply and still work. Try it with your students - you're sure to see improvement.
By Lawrence J. Minch