Square Dancing

Ground reference maneuvers, introduced early in the private pilot training curriculum, are often treated as purposeless exercises. They're not. Flying precisely through the rectangular patterns, S-turns across a road, and circles around points on the ground does have a purpose.

Flying a rectangular pattern introduces you to the tasks associated with flying in a traffic pattern at your airport.

S-turns along a road teach you how to plan for the effects of the wind on your turn radius. You can't use the same bank angle throughout the entire turn.

The turn around a point requires a continual circle of a constant radius. The size of your circle will depend on the speed of your aircraft.

Like slow flight, coordination exercises, and blind radio announcements, learning to perform these ground reference maneuvers will prepare a student pilot for more complex tasks that use similar skills. New students can't jump into the rapid-fire sequence of a traffic pattern right after learning the four fundamentals of flight. The technique of placing the aircraft in neatly squared-off descending legs leading to and from the runway must be approached like eating an elephant--one bite at a time.

Before the introduction of ground reference maneuvers, most of the flight training out in the practice area probably had been done at 1,500 feet or more above ground level (agl), with heavy emphasis on holding a specific heading, airspeed, or altitude. Up to this point, the use of outside references has been limited to watching for other traffic, holding the correct attitude relative to the horizon, and making clearing turns before maneuvering. But now there's an additional responsibility--flying while looking at specific targets on the ground.

This requires the student to divide his or her attention among the instrument panel, the natural horizon, and the reference points on the ground. Juggling these tasks is exactly what's needed to bring the aircraft back to the airport runway, when it has to follow a precise ground track. As a student, this is when you learn that setting power and attitude allows the airplane to fly itself for a few seconds while you look for a road or reference point--it's not necessary to stare at the gauges every second.

By learning to shift attention in and out of the cockpit, students can adapt to the demands of a traffic pattern or other micro-navigation tasks. For effective training, all ground reference maneuvers must be done at approximately 1,000 feet agl, to replicate the perspective of the airport traffic pattern. Almost without fail, newly soloed students will practice them at an excessively high altitude, the familiar height used for steep turns and stalls, until they're reminded to descend to pattern altitude.

Why fly so low? Because it enlarges the landscape that forms the focus of your attention when performing ground reference maneuvers. Obviously, you should choose a practice area where an airplane at pattern altitude won't bother persons on the ground. Rising terrain or tall obstructions, and a suitable place for an emergency landing, must be given consideration as well.

Square dancing

I normally introduce students to the rectangular pattern first, hopefully on a day with winds of 10 knots or more blowing perpendicular to the longer side of the rectangle. For the average training aircraft, a set of roads a mile apart is ideal. I fly along a lengthy stretch of road while pointing out that the crosswind is blowing us to the left, toward the rectangle, which should be paralleling the road. I then transition to a crabbed heading that holds our track parallel to the road. It's like a boat attempting to reach a dock directly across a swiftly flowing river, I explain; you have to point the bow of the boat upstream, against the current, to get where you want to go.

It's best to position the airplane slightly to the right of the road, so the pilot seated on the left has a clear view. As we approach an intersection, I explain that we'll be turning left to follow the upcoming road. After rounding the crossroads onto a downwind heading, it will be noted that we are moving across the ground at a much faster clip than before because of the tailwind. However, a glance at the airspeed indicator (ASI) shows no change--the ASI shows only speed through the air, not across the ground.

The mile goes by quickly. We soon approach another road intersection, where a left turn will bring us onto the next leg, dominated by a crosswind. I ask, "Will this turn be 90 degrees, less than 90, or more than 90?" and the usual answer is "90 degrees," anticipating the right angle to be made. No, I remind the student; we'll have to turn more than 90 degrees, in order to set up the crab angle needed to stay on the crosswind track. These low-level maneuvers are all about learning to plan ahead; anticipating one's next move is a vital part of flying traffic patterns.

With the arrival of yet another intersection, it's time to turn upwind to fly back to the original road. As seen out the window or by the GPS, the groundspeed now drops to a relative crawl, as the headwind extracts its toll from the unchanging airspeed. Again, we stress that indicated airspeed is just that--speed through the air, not across the ground. Now, it's time to anticipate the next turn; will it be 90 degrees, less or more? This time, the student correctly answers "less than 90," showing understanding of the need to crab into the wind.

On the next circuit, we'll apply a wind correction during our turns. To demonstrate the principle, I first head upwind over a landmark, roll into a steady 30-degree banked turn for 360 degrees, and roll out on the entry heading. I point out that we have moved downwind during our turn, drifting across the ground to a displaced conclusion instead of returning to the original starting point. Once over the point again, I repeat the maneuver, but this time I begin by rolling into a shallow bank of perhaps 20 degrees, which keeps our ground track from moving downwind so fast. Upon reaching a crosswind position, I steepen slightly to a 30-degree bank; then when we reach a downwind heading I'll nudge the bank into an angle steeper than medium, say 40 degrees instead of 30 degrees. I explain that this is the time to add more back-pressure on the yoke, to prevent altitude loss from the steeper bank. As we round the downwind position we'll return to the medium bank angle and soon find ourselves back over the starting point--having seen that altering the bank angle works to offset the wind's drift during our turn.

Armed with this knowledge, another rectangular pattern is flown, this time using a shallow bank when turning from upwind to crosswind and a steep bank when turning from downwind to crosswind. This keeps the spacing from the rectangular course markers (roads or fence rows) even and on track. Like life, it's all about relationships; in this case, the airplane's relationship to a line on the ground.

You have now acquired the basic knowledge of how to maneuver in relation to a ground object, despite the wind's perfidy. Crab angle is the difference between the aircraft's heading and track; bank angle can be used to offset wind drift during a turn; and groundspeed is not the same as airspeed when wind is acting on the aircraft.

S-turns along a road

S-turns across a road require flying 180-degree turns on upwind and downwind sides of a line oriented perpendicular to the wind. The goal is to cross the road just as you roll wings level, going from one turn directly into another in the opposite direction. This requires advance planning, as well as knowledge of the wind's effect on turn radius. Entered on a downwind heading, a steep bank is established as the reference road is crossed. However, the steep bank is only needed until just past the halfway point of the 180-degree turn, where the bank is shallow to medium or less. Remember, you can't use the same bank angle through the entire 180 degrees of turn, because the wind's relationship to our flight path is changing.

Ideally, you'll roll out of the turn just as you cross the road, and without hesitation enter into a shallow bank in the opposite direction, necessary because of the headwind retarding forward progress during the first part of the turn. As the airplane passes the midpoint of the 180-degree turn, the bank must be steepened to a medium bank to increase the rate of turn, because groundspeed accelerates your progress toward the road. Rolling wings level just as you cross the road, the roll is continued into a steep turn in the opposite direction, to start the S-turn again.

The beauty of this maneuver is that it always gives the student an opportunity for a fresh start, even if mistakes are made on one attempt. Altitude deviations should be held within 50 feet or less, advance planning is required to cross the road axis exactly on cue, and the proper bank is needed in the proper place to maintain equal-size loops on both sides of the road. As I say to my students, "Keep one eye on the bank, one eye on the altitude, and one eye on the road."

'Round and 'round it goes

After mastery of the S-turn is achieved, it's time to make full circles around a point on the ground. Select two lines that intersect, like a crossroads or fence row crossing--I find those better than a lone tree, barn, or water tank. The crossing lines aid orientation if a wing tip blocks the view of the point you're circling. Try to select maneuvering points away from houses and fly no lower than traffic pattern height.

Entered on a downwind heading, the turn around a point is begun with a steep bank, which continues just past the crosswind position. Here a transition to a medium bank is made, continuing around the upwind side of the turn, when a shallow bank must be used to avoid drifting back over the point. Note that the wing tip does not continue to point directly at the spot being circled; the crab angle necessary to offset wind drift during the turn causes the nose of the airplane to point toward the outside of the circle on the upwind side of the circle and toward the inside on the downwind side. The reference point's position in relation to the wing tip changes accordingly.

This maneuver does not offer the periodic relief of the S-turn across the road, instead requiring a continuing turn. The size of the circle depends on the speed of the aircraft. A quarter-mile radius works well for a 95-knot airplane, with a half-mile easier to manage at 130 knots. Altitude is held constant.

Simple in design, yet complex in execution, the ground reference maneuvers can teach you much about planning 10 seconds ahead, dividing your attention among competing priorities, and flying while looking outside. They aren't going to be used every day of an ordinary flying career, but if you'll take the time to perfect them, they'll advance the skills you'll need to fly a good traffic pattern, takeoff, and landing--things you will use every time you fly.

LeRoy Cook has been an active flight instructor since 1965 and has had more than 1,350 articles published. He is also the author of 101 Things to Do With Your Private License and Flying the Light Retractables.

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