Ground Reference, Part 1

We arrive at the airport at 10 a.m. for our third lesson with Walt Blumenthaller in his Challenger. In the first two we did basic turns, climbs, and glides, and learned how to use the trim to make the plane fly hands-off.

Today, Walt says we're going to do "ground reference maneuvers" and learn to fly the plane over a precise path across the ground. In the earlier lessons we were at altitude and didn't pay all that much attention to what we were flying over.

And today, the wind is up. Walt says it's about 10 mph and from the south at altitude, but it doesn't seem that strong on the ground.

1. Crosswind Takeoff

“Davidson County traffic, Challenger niner Whisky Bravo departing on Runway 24 Davidson County.”

We pull onto Runway 24 and line up on the center line. We've just completed the runup and mag check and set the altimeter to the field elevation of 700 feet. We are ready to take off. From the back seat, Walt explains ...

“We've got a bit of a wind coming from our left, so this will be a crosswind takeoff. What I like to do in a wind like this is to keep all three wheels firmly on the ground until we reach about 40 mph. That's about 5 mph faster than what we normally do. Then, pull the nose up fairly quickly and lift the plane into the air. Don't jerk it; be smooth, but be smooth without delay.

“It'll probably take a bit more right rudder than usual because the wind from the left, blowing against our tail, tends to make the plane weathervane to the left. Ya ready?”

“Yep, ready in the front.”

“Let's go!”

We release the brakes and push the throttle forward, smoothly, all the way. The nose immediately starts to the left as the plane begins to roll, but right rudder stops it. The plane picks up speed quickly. We keep the stick neutral rather than exerting the backpressure to take the weight off the nose.

As the airspeed passes through 35, moving toward 40, we get ready. When it hits 40, a quick but smooth backward movement of the stick causes the plane to jump off the ground. As it comes off the ground, the nose swings left abruptly as it weathervanes into the wind. More right rudder to keep it straight ...

“Let it swing to the left!” says Walt as we feel him override our right rudder. “And not too high too quick ... lower your nose and get your airspeed up.”

Releasing the back pressure a bit lets the airspeed climb up to 55 mph. The plane is crabbed a few degrees to the left but is traveling straight down the runway as it gains altitude quite rapidly. The “lumpy air” causes the wings to bob up and down more than normal, but small movements of the stick are all that is required to keep them level.

“Walt, shall we trim it out?”

“Nah, no need to bother. We're only going up to about 500 feet above the ground. You can make the radio call for a straight-out departure if you wish.”

“Davidson Country traffic, Challenger niner Whisky Bravo departing straight out from Runway 24, Davidson County.”

Soon the altimeter is approaching 1200 feet. We ease the nose forward and as the airspeed starts building, we pull the power back to 5700 RPM. In just a fraction of a minute, the airspeed stabilizes at about 65 mph. We're now straight and level.

After flying a couple of miles out from the airport, Walt says, “Let's turn 90 degrees to the right, and when you get established on that heading, you can practice your turns just to get the feel of this thing again.”

2. Coordination Practice

Right stick and right rudder simultaneously causes the plane to roll to the right. Once the angle of bank reaches about 30 degrees, we neutralize the controls and apply stick or rudder only as required to maintain the angle of bank and to keep the skid ball centered. And, a bit of backpressure on the stick keeps the nose from dropping. We don't want any more of that graveyard spiral business we had in our first lesson. We roll out headed toward the northwest practice area.

Walt says you don't have to make a full 90 degree turn to the left or right when practicing coordination. For example, set up a turn to the left and once the turn is established, roll the plane out of the turn and go immediately to a bank to the right. Then roll it to the left again.

Considerable fore and aft stick pressures are required to stay level while doing this. In a bank, backpressure is required to hold the nose up, but when the plane rolls back level, the backpressure must be released or the nose will climb.

After we sort of get the hang of this, we note that the nose of the plane seems to follow a half circle hanging down from the horizon. When we use the stick and rudder to make the nose move along this circle, the skid ball stays in the center and the plane seems to be “comfortable.”

Walt says, “Enough turns for now ... level it out and then make it go up and down like a roller coaster. Start out easy.”

Hummm .... Wonder what's up now? OK. Stick forward, gently, and the nose drops below the horizon. The airspeed begins to build up. Then back stick causes the nose to rise, and the airspeed drops back down. Forward pressure again, and the nose comes back down.

“Be a little more aggressive with it,” says Walt over the intercom.

So, stick forward, nose moves down, and we feel the plane picking up speed. Then backpressure, and the nose comes up. This time, we feel a slight G force as we pull the nose up, and the nose goes up considerably higher than before. Stick forward, and the nose goes down again, and we feel a slight floating sensation as the plane goes over the top.

“OK, so far,” says Walt, “but you're still holding back a little. Put the nose way down, and then pull it way up. When you go nose down, reduce the power a little, and when you pull up add a bit of power. This will keep your airspeed from varying so much.”

Oh boy. Here we go. Nose down ... reduce power. The nose goes way down.

“Now pull up, but keep it smooth!”

And we pull the nose up and feel the G forces as the nose rises back to the horizon. Add power. Nose goes up, way up! Airspeed is dropping quickly.

“Now get the nose back down before you stall!”

Forward on the stick ... We suddenly feel light in the seat ... and release the forward pressure because we don't like the floating feeling.

“Nose down, or you're gonna stall!”

So, forward pressure again ... the floating feeling ... and the nose comes down level with the horizon. Reduce power back to normal.

“Not bad,” says Walt. “Try it again now, and be smooth with it all the way.”

This time, we expect the G forces as we pull the nose up, and the floating feeling as we go over the top. Everything happens as we expect it to. It's almost fun!

“Hey Walt, what's the purpose of this?”

“Ain't got no purpose. It's just fun to do. But now do the roller coaster thing at the same time you do a turn.”


“As you lower the nose into a dive, do a turn to the left. As you raise the nose, roll out of the turn to the left and enter a turn to the right. Ya got that? Nose down, turn left; nose up, turn right. Start out easy. ... Well, go ahead!”

Here we go. Nose down, bank to the left, reduce power. As the nose gets down “far enough,” we begin to roll back to the right and pull the nose up. Add power and enter a bank to the right. After the nose is way up, the airspeed begins to drop, so we begin to lower the nose and roll back to the left. When the nose gets back to the horizon, we level the wings and return the power to normal.

“Hey Walt, how was that? The ground really moves around doesn't it!”

“It was awful. Your coordination was totally out of whack. Almost made me sick!


And Walt continues, “In doing this, the amount of rudder you have to apply is constantly changing because the airspeed is constantly changing. You have to stay with it the whole time. Try it again.”

A few more tries at this and the plane seems a lot more comfortable. We note that it takes a lot more rudder when the plane slows down. Less rudder when it is going fast. It's more apparent when reversing the bank while going over the top.

“Enough of this!” says Walt. “I can't stand it any more! !! “

Then he adds, “That is good coordination practice. If you can keep the ball centered while doing that, you're pretty good. Or even better, don't even look at the ball but keep the plane feeling comfortable. The seat of your pants is a better indicator than the ball anyway.”

3. Tracking a Power Line

“We're supposed to be doing ground reference maneuvers. Go down a couple hundred feet and follow that power line over there. Stay right above it. Don't let the wind blow you off to either side.”

“Hey Walt, which way is the wind blowing?”

“Don't you know? Any pilot worth his gas always knows which way the wind is blowing.”

We look around ... it was blowing from the south, but which way is south? You can't tell which way it's blowing once you're in the air.

Walt adds, “Look around for a column of smoke. You can often see smoke rising from a fire or something, and you just see which way the smoke blows.”

We look all around. There is no smoke anywhere to be seen.

“I don't see any smoke, Walt.”

“OK. Don't worry about it. Just go fly along the power line.”

We turn gently to the right and line up with the power line. It's long and straight for miles. Easy to see where it goes through the woods. We level off about 300 feet above it.

“Hey Walt, isn't this kinda low?”

“Well, yeah, a little bit. But we'll be OK if you keep this thing nice and level.”

As we begin to fly along the power line, the plane seems to drift to the left. We bank and turn slightly to the right to get back over the power line, and then line up with it again.

Again, the plane drifts to the left. Another turn back to the right to get back to where we need to be. And it drifts back to the left.


Ah, yes. The obvious. We set up a crab to the right to offset the drift to the left. Now the plane tracks straight down the power line, but it seems to be flying sort of sideways. That must be the wind!

“Hey, Captain, which way is the wind blowing?”

“It's coming from our right, Sir.”

“Very good!”

4. Flying a Rectangular Track

After flying a mile or so along the power line, Walt says to turn left and fly up toward those two water towers on the horizon. Those are the Churchland “twin towers.” Easy to spot from miles away. We climb back up to about 500 feet above the ground.

Just before we get to the towers, we come upon a large smooth-looking field. Walt says to fly around this field. But fly a rectangular track with straight sides and sharp corners. We will make left turns around the field.

We begin by entering straight in on one of the long sides. We're now headed almost due north, about a quarter mile, or maybe less, from the field. Airspeed is 65 mph. Soon we're to the point where we turn left to go across the field. We set up a 30 degree bank, just like in a traffic pattern, and bring the plane around until we're headed almost due west, a quarter mile from the end of the field.

Uh oh! The plane is drifting away from the field. We turn left to get back on track, but the drift comes in again when we try to fly due west.


Oh yes, the obvious again. How could we forget? The wind from the south is blowing us away from the field. Soon it's time to make another turn to the left.

We bank our standard 30 degrees and turn parallel to the field. Now we're headed due south and straight into the wind. No crab necessary this time, but our ground speed is obviously much slower than what it was. This part is easy.

Now it's time to turn across the field. We set up the turn and roll out headed exactly perpendicular to the field, but the wind is blowing us toward the field. We turn back to the right and set up a crab to offset the wind.

Walt comes on and says, “See what you're doing? You're making your turn and then, later, after you get blown around all across the sky, you set up your crab. Why not do it all at once, now that you know which way the wind is blowing?

“Once you make this next turn, which way will you be headed? Due north, down the long side of the field. You've got to turn actually more than 90 degrees because of the crab you now have. So, make this turn a little steeper. That will help you cut a sharp corner over the ground.”

At this point it's time to start the turn, so we really get into it. Angle of bank goes up close to 40 degrees. And it takes a lot of backpressure to keep the nose from dropping off. But the Challenger turns sharply, almost on a dime! We roll out flying parallel to the field. That's good!

“Airspeed!” says Walt.

Lo and behold, the airspeed is all the way down from 65 to 45 mph! The engine RPM is still at 5700. And we're level; didn't climb in the turn. Don't want to put the nose down to gain airspeed because that would cause us to lose altitude.

“What do I do to get the airspeed up, Walt?”

“Well right now, don't do anything. Just watch it.”

And the airspeed builds back up to 65 mph, which is normal for 5700 RPM in straight and level.

“What caused the airspeed to drop?”

“When you were in the turn, fairly steep, you were pulling a lot of backpressure. This produces more lift from the wings, and more drag. The extra drag caused your airspeed to drop.

“Normally, when we do a steep turn, we add power while we're in the turn to keep the airspeed from dropping. Any time the bank gets over 30 degrees in a level turn, you can expect to need extra power.

“You've got another turn coming up here shortly, and it'll need to be steep as well because you're now going downwind, and you've got to turn more than 90 degrees to set up the crab. Try adding a couple of hundred RPM as you roll into the turn.”

Fairly aggressive stick and rudder action puts the Challenger in a 40 degree bank. As the turn develops, we add power smoothly up to about 5900 RPM as we apply the stick backpressure. The plane turns quickly and the airspeed drops very little, if at all. We let the plane turn on into the crab before rolling out. As we roll out, we release the stick backpressure and reduce the power back to 5700 RPM.

“Ah, very good,” says Walt. “In this next turn you'll be turning upwind and less than 90 degrees. It calls for a shallower bank than normal.”

Sure enough, with about 20 degrees of bank, the plane comes around and turns the corner just about as sharp as with the 40 degree bank earlier. Also, our ground speed is much less going into the wind.

As we work our way back toward the other end of the field, Walt says, “What about this next turn? What are you going to do?”

“Hummm ... We'll be turning crosswind, less than 90 degrees to end up in a crab. Our ground speed is low. I think it calls for a shallow bank.”

“Well, go ahead when you're ready, and see what happens.”

Somewhat cautiously, we bank to 20 degrees, glancing down at the field. The Challenger comes around smoothly, and we roll out when we reach the crab angle we've found necessary to compensate for the wind drift. The corner was fairly sharp, and we're not drifting toward the field.

“It seemed to work, Walt.”

“Of course it did. You're a natural-born Aviator!”

Good ol' Walt. He always keeps you guessing. The next turn is downwind and more than 90 degrees. This calls for a steep turn, and a steep turn calls for power. We do it. Airspeed holds steady, the corner is fairly sharp, and we roll out headed exactly parallel to the field.

5. Turns about a Point

As we fly downwind parallel to the field, Walt says, “See the Churchland twin towers over there on the hill? Go over there and fly a circle around them. Stay the same distance from the towers, all the way around.

“Look at the towers, and mentally trace a circular track on the ground around the towers. All you gotta do is fly over this imaginary track.” Then he adds, “I shouldn't give away my secrets. Makes it too easy.”

Uh oh. When Walt says something is going to be easy, it usually isn't. OK, trace a path on the ground around the towers ... got it. Now, a slight turn to the left and we should intersect the track while going downwind, mostly.

As we arrive over the circular path, we roll into a 30 degree bank. The plane begins to turn just like in any other 30 degree bank, but the wind blows us way on past the circle on the ground. Oops. Steepen the bank to get back onto the track. We're holding backpressure, and we even remember to add power to keep the airspeed from dropping.

As we come back over the imaginary track on the ground, we lessen the bank to about 30 degrees, and reduce the power a tad. We're staying over the track pretty good now. We're halfway around the towers the first time. Now maybe, if we just hold everything still ...

As the plane works its way upwind and starts turning crosswind, it begins to drift toward the towers. As we go further around, the drift picks up speed and we get blown almost straight across the top of the towers. How embarrassing! What's Walt gonna say now?

This is a lost cause, so we roll out nearly level to get back over above the circular path on the ground. Then, a fairly steep turn from the downwind part to crosswind. We add power, hold backpressure, ... the whole bit. This time we don't get blown quite so far. In fact, we stay pretty well over the imaginary track.

As we work on around to where we begin turning onto the upwind side, we reduce the angle of bank back to about 30 degrees. So far, so good. We're now flying upwind, over the track. But here's where we lost it last time.

We're bound and determined not to get blown back over the towers. We reduce the angle of bank to something real shallow, like maybe 15 or 20 degrees. The nose of the plane is coming around very slowly, but we're still above the track on the ground. Must be the effect of the wind ...

Oops, as we get around to the downwind side of the circular track, we start overshooting the track on the ground. Overshooting, and by a lot! We steepen the bank to 40 degrees, pull backpressure, and the Challenger turns sharply. We're just slightly outside the track now, getting ready to reduce the bank back to normal ...


Uh oh. Airspeed is 45 mph. Forgot to add the power in the turn. Better late than never, so we run the RPM up long enough to get the airspeed back to near 65.

We're just sailing around this side of the circle! Gotta steepen the bank again to get back onto the track. This time, we add the power, as the nose comes on around.

Soon we're approaching the upwind side once again. We pull the power back to normal. This is the side where the bank is shallow. Glory Be! We're above the track. We continue on around, keeping the bank shallow, and then it's the steep turn downwind, with power, all over again.

We continue on around to the other side of the towers, flying upwind, when Walt comes on the intercom, “Well, have you had enough of this yet? Let's straighten up and fly back over the big field we flew around a while ago. Take a good look at it.”

6. Tailwind Landing

Now wonder what Walt's up to! As we fly straight across the field, we see a bunch of trees off to one side, and on the other side of the trees, a house with a swimming pool. “Nice place!”

“Yeah,” says Walt. “Look over next to the trees. What do you see?”

“There's an airplane parked down there!”

“Bingo,” says Walt. “It's an airstrip! And straight across the field from the plane, there's a wind sock. See it?”

“Sure do.”

“Now I think we oughta land down there and stretch our legs a bit. So, circle around and look everything over, and tell me which direction we should land.”

Hummm ... the windsock is being blown toward the north which means the wind is coming from the south. We always take off and land into the wind, so ...

“Walt, we should land headed toward the south, into the wind.”

“Are you sure?”

“Well, that's what the book said. Take off and land into the wind.”

Then in a slow deliberate voice, Walt says, “Well, that's not good advice for us right now. We need to land headed toward the north. Can you figure out why?”

“No, not really. Care to give me a hint?”

“OK, if I have to draw you a picture, ... look up at the north end of the field, up next to the road. What do you see?”

“There's a fence and two light poles.”

“Very good! ... now we don't care about the fence, but what is likely to be strung between the two lightpoles?”

“OK, I get it. Wires. There's a power line up there next to the road, and if we came in from that direction, we would have to cross the power line.”

“Right on!” says Walt. “And at ground level the wind is probably not as much as it is up here, so I prefer to land with a little bit of tailwind rather than to have to cross the power line and then get down to the runway.

“So turn back across the field and set up a pattern just like we do at the big airport. It'll be a lot like flying that box you were doing a while ago.”

So, two left turns later and we're on the downwind leg of the pattern ... which is actually upwind in this case. The field is beginning to be behind us and we're thinking about when to turn onto base leg.

“Lets extend on out a bit farther than normal because this is going to be a tailwind landing. Our ground speed will be greater on final, and our angle of descent will not be as steep. Pull the power back to about 5000 RPM so we can start slowing down.”

We go on out perhaps three-quarters of a mile, and then turn base. It takes a shallow turn just like before to get a nice, crisp 90-degree corner on the ground, and we roll out with the nose to the right of our intended path to correct for wind drift.

Just as we get set up on base, Walt says, “You'd better start your turn onto final now. Keep the bank to 30 degrees or less. Get the airspeed to 50 mph and hold it there. Pull the power back to 4700.”

We begin a gentle gliding turn onto final and adjust stick backpressure to hold 50 mph. We sink rapidly in the turn but as we roll out onto final, the sink rate becomes much less. Even so, we're losing altitude steadily.

“Hey Walt, there's a tree on final!”

“Really! I didn't hear its radio call.”

“No, Walt, the tree on the ground, right in front of us. Are we gonna make it over it?”

“I think so. Look at the very top of the tree, where the tip seems to touch the little road that runs just below this end of the runway. See what I mean?”

“Yeah, I see the tip touching the little road.”

“Now here's a trick. As long as you adjust your descent so that the tip of the tree does not seem to rise up above the road, you'll clear the tree OK. If the tip of the tree starts rising, add a bit of power. Hold 50 mph.”

And wouldn't you know it, the tip of the tree slowly starts rising up into the road. We add a bit of power, ... and the tip of the tree starts going back down again. Amazing! With just the right amount of power, the tip of the tree stays put.

We continue on, holding 50 mph, but as we get lower and closer to the tree, we seem to be going faster, like speeding up. Airspeed is right on 50, but it looks FAST!

“Walt, aren't we going too fast?”

“What's your airspeed?”

“50 mph.”

“We seem to be going fast because we really are. We've got a tailwind, remember? The wind is helping to blow us along. Keep your eye on that airspeed and you'll be OK.”

We continue the approach and are getting close to the tree. “Walt, are we OK with that tree? It looks tall, and we aren't much above it!”

“We're OK. Keep on driving. Watch your airspeed. You're looking good.”

We cross the tree. Now the end of the strip is just a few hundred yards away. Airspeed is 50. We're lined up to go right down the middle of the field.

“Hold everything right where it is,” says Walt.

We continue. Things on the ground really seem to be zipping by fast. We cross the end of the strip at an altitude of about 20 feet.

“Pull the power all the way back to idle now. Let the plane go right on down. Use the rudder to keep the nose pointed straight ahead.”

As the plane descends down to within only a few feet of the ground, Walt provides a bit of assistance. The stick comes back ever so slightly and the plane flies parallel to the ground. As it slows, the nose rises ever so gently, but the plane is settling toward the ground. And then, the wheels touch down.

The stick is now almost all the way back. The nose is still high; the nosewheel is not yet down. We can feel Walt playing the rudder pedals back and forth a small amount. Then the nosewheel drops, and we're rolling out, slowing quickly.

“Whadaya think of that?” says Walt. “We missed the tree, landed downwind, and still have half the field left in front of us.”

We taxi on up to the end of the field and pull up onto a little rise off to the left side of the “runway.” We click the avionics switch OFF, and then a quick click, click of the mag switches and the 503 shuts down.

“Hey Walt, there's the power line. But it's not all that tall. I think we could have landed over the top of it OK.”

“Yeah, you're right. It wouldn't have been any problem, but then we would have come to a stop at the other end of the field. The “facilities” are at this end.”

(Continues with Ground Reference, Part 2)

Author:   Doc Green