This chapter is about all the stuff you already know.
Why should we go back and revisit turns,
Let's start with runway numbers. Your home field, for example, might have just one runway, a 10-28. So you know that 100° is the reciprocal of 280°. You just know. You don't have to think about it. You can't imagine how useful it is on a dark night in bad weather to just know something. Your brain is free to take care of the important stuff. So what we're doing here, in Chapter One, is putting together some learning habits that will stay with you your whole career and make you a whole lot smarter when the chips are down.
You can see where this is going. Perhaps you flew your first cross-country into an airport where there were three runways: a 07-25, a 14-32, and up to the northwest, a smaller 04-22. Now you know three more sets of reciprocals and you associate them with that second airport. Every time you fly into a new field, add it to your collection. And when you are riding a bus or waiting for a friend to show up, don't waste the time: start with 01-19 and work your way around the compass, visualizing the airport runways you first associated with those numbers.
As you get good at it, add the IFR stuff: for example, perhaps the actual track of your home runway is not 10-28 but 097°-277°. You knew it before but now you see it on the approach plates. And when you are doing an approach, you will need to be able to visualize – instantly and accurately, without thinking about it – headings that are 10 degrees, 5 degrees, and two degrees to each side of the published runway track. So for that approach to runway 28, you will have 267°-277°-287°; 272°-277°-282°; and 275°-277°-279°. If this seems like a silly exercise, try doing it for your home runway before you shoot your next practice approach. (You will find it is easier to shoot a good approach.)
When you strap into your seat, your IQ goes down fifty points. When you get too busy and get overloaded, it goes down another fifty. Would you fly with a pilot whose IQ is a hundred points lower than yours?
Perhaps your instructor has already had you doing some airwork under the hood. He'll say, turn to a heading of 240. Let's work that out here, on the ground, where we have that great triple-digit IQ.
First, was is our present heading? Let's say it is 010. Do we turn left or right?
If we have been practising the Einstein Thought Experiment with the runways, the answer is obvious. We know we are heading just east of north; we can see it in our heads. We can see runway 06-24, as well, from some airport. We can visualize the threshold of 06 ahead of our right wing, and the threshold of 24 (perhaps on a different airport, but it doesn't matter) behind our left wing. We start the left turn without thinking about it.
So we roll smoothly into a standard rate left turn. All IFR turns will be standard rate, unless there is an emergency or you are practicing steep turns.
Now what? Check the clock and wait forty seconds. Well, with our example it is 43.3333 seconds, but close enough. Even if you know it will take more than half a minute but less than a minute, you have gained something: some useful brain time. Perhaps your instructor has also asked you to start a 500 fpm descent from 4000 to 3000 feet. This is your chance to pull the power back 5 inches or 500 rpm, check the nose drop with elevator, and re-trim. You have plenty of time to call Leaving four for three and to feel the airplane settle into the descent and to fine-tune the bank angle (it will be 15 degrees at 100 knots). You know you will be rolling out onto your heading of 240 long before you have to level off at three thousand. You know instinctively, because the descent will take you two minutes and the turn forty seconds. That is why we practice airwork: we want these maneuvers to become instinctive. They have to become instinctive, otherwise we won't have enough brain left for the many other tasks that pile up in IFR flying.
This is a good time to peek ahead at a very important subject: overload. You can easily tell if you're overloaded – your cone of vision narrows. And don't worry: even the most experienced pilots get overloaded. The advantage they have is that they know they are overloaded. And so can you. As you do your basic instrument scan, how much can you see? Are you aware of the engine instruments and the GPS in your peripheral vision? Or can you see just the basic T? Or worse, when you check your heading on the DG or HSI, does the AI disappear?
What is a Heading Change?
We learned the answer in the above section: a standard-rate turn for a period of time. So what, you might say. But hidden here is important idea, one of the foundations of physics. Isaac Newton and Gottfried Leibniz invented the Calculus at the beginning of the eighteenth century. We will be returning to their ideas again and again, not to learn math, but to get a better understanding of the laws of motion, which are basic to our trade.
For now, we will make the observation that holding a turn for a period of time changes our heading. So what, you say. That's obvious. Yes, it is. It is so obvious that before Newton and Leibniz no one could see beyond it. They did and gave us the Calculus, which can figure out what heading we have turned to even if we keep changing our bank angle and our airspeed. They called it Integration and that is what is being done continuously inside an Inertial Navigation System. You do it when your instructor gives you heading changes in partial panel. You use the Turn Co-ordinator to hold a standard-rate turn and the clock to time it, so the math is simple, but it's still Integration.
Holds can help
Perhaps now it makes more sense that we maintain a certain discipline when flying IFR. Standard-rate turns, precise airspeeds and rates of descent. Cleared routes, airways, published approaches. Standard Operating Procedures in the cockpit. All this is part of keeping the picture in our heads, the picture which some day will make the difference between life and death. (If you think I am exaggerating, read the transcript from AF 447).
One of the most effective ways of getting the picture is to practice holding. Each hold has a defined pattern and an entry determined by the direction of your approach to the fix. Each hold and entry is a series of turns to heading. There are many methods and tricks for determining the entry and they can be a great help. But the object of the game is to be able to see the hold clearly in your head. Next time your instructor gives you a holding clearance, think about it first. You are probably proceeding direct to the holding fix, or will be shortly. Use your finger and trace the hold on your DG or HSI. Go around the whole racetrack and make sure it makes sense: right turns? Inbound track to the fix? We'll go into this in more detail later, but if you get into the finger-tracing habit, before long you will see the picture and the entry will be obvious.
Reduced airspeed is used for holds and approaches. In some fixed-gear light airplanes there won't be a huge difference from cruising speed, but as the airplanes you fly grow larger and more complex that speed difference will increase dramatically. In a jet transport, for example, you may be descending at 320 knots or higher. Then you have to slow to 250 below 10,000 feet, and to 200 knots within 4nm of the airport. Once on approach you will get further speed restrictions from ATC and have to take flap, and at the marker you'll take approach flap and slow to Vapp.
All this is to say that speed transitions are something you should be good at – something you understand instinctively and can do in your sleep. Of course this is not as obvious in a C-172, where you might want to slow to 100 from 120 when you get near the holding fix. But you can see that slowing from 320 to 160 takes more planning.
Let's go back to a basic airplane – perhaps even more basic than the one you have in your logbook for your first solo. Let's do our Einstein thought experiments in a Piper Cub, the J-3. I haven't flown one myself in forty-odd years, but I would jump at the chance to do so tomorrow. The J-3 is as basic as you can get, but it is also sweet and co-operative. That's not test-pilot talk, obviously, so here is a translation: the J-3 has exceptional control harmony and linear stick-force per G. Control harmony means that the flight controls – elevator, aileron, and rudder – have the same feel: a one-pound force gives pretty much the same attitude displacement with each. (In contrast, the Aeronca 7AC is harmonious in rudder and elevator but somewhat heavier in the ailerons.) Linear stick-force per G is a property of the elevator and means just what you would think: if you made a graph of back pressure vs. G force, it would be a straight line. To the pilot that feels like nice handling. The airplane is “sweet” – flattering to the ego. It will likely also land nicely, if it has a high wing or the the landing gear is long enough to keep the wing out of ground effect.
So here we are doing our Einstein thought experiment, doing speed transitions in our J-3. For the sake of argument we'll say that the J-3 stalls at 50 mph and cruises at 90 mph. As in most airplanes we'll do the approach at 1.3 Vs: in this case 65 mph. Let's practice the slowdown from 90 to 65 a few times in our heads, trying to note all the details of how it looks and feels.
As we we reduce power, observe and feel that the nose drops (this is the airplane's longitudinal stability). Check the nose drop with elevator, holding attitude (if we are transitioning to a descent) or altitude, if that's what we want. Feel how we need more back pressure as the speed drops. Trim to remove the back pressure. When we reach 65 mph, add throttle to “catch” the speed and re-trim.
That's it. Reduce power, check nose-drop with elevator, hold attitude or altitude re-trim as the speed drops and finally “catch” the new speed by adding power. (Of course there are many variations on this theme: on a power-off approach, for example, you'll pull on carb heat and close the throttle, and trim to glide at 65 mph.)
I know you have done this maneuver many times. But what image remains in your head? Can you see and feel the essentials? Your next landing will benefit from this exercise as well. After flaring and reducing power to idle, you “hold it off”, as your instructor taught you. In most airplanes you can do it just by holding attitude – in other words, after the flare just keep the nose from dropping and you'll do a nice landing.
So what's the point in talking about J-3's and landings when what you want to do is fly instruments?
This is another point where we can look ahead a bit. Flying instruments is still flying. There is no difference from VFR flying except your references. Instrument flying is flying by reference to instruments. If you have the right picture in your head about what you are doing, it will make no difference whether you are looking outside or inside. Even in a modern glass cockpit with all the bells and whistles, flying is still flying. The glass makes a nice picture, but if the picture in your head is wrong or isn't there at all, your flying will suffer and you will become overloaded easily. If you get the picture, you will be a better pilot.
So the point in talking about J-3's and landings is to develop a new learning discipline, a way of thinking about flying that puts a picture in your head, a way of flying where you transition effortlessly from outside reference to instrument reference.
Maintain the published track and you'll stay on the airway.
Sounds simple. Makes sense. But it's not instinctive. You have to think about it.
Here's another thought experiment. You are running a train down a straight track. You can't see outside. You have a stopwatch, a remote paint-gun, and an accurate speedometer. Your task is to make two marks on the track a mile apart.
Simple, right? You accelerate to 60 mph, hit the paint-gun remote and the stopwatch at the same time. Exactly 60 seconds later you hit the paint-gun remote again. Mission accomplished!
But what if you are flying an airplane doing 120 knots? You are on (over) the track and you hit the paint-gun. You wait 30 seconds and hit it again. Where is the second blob of paint? Sure, it's 1 nautical mile ahead, but is it on the track?
Yes, if your track hasn't changed. That's easy for a train but a big IF for an airplane. The wind could change. Your heading could change. Then the second blob of paint will not be on the track. It will be off to one side. Your VOR needle will be off to one side.
In math this is another example of integration. You are adding up what happens to your position as a result of your velocity vector. The INS or IRS in an airliner does it. Experienced pilots do something like it in their heads.
If you have a Garmin 430 in your airplane you can go to NAV page 1 and fly so TRK is the same as DTK. If you don't you'll have to do it the old-fashioned way, flying heading to compensate for drift. Either way, try to have the picture in your head.
Integration and Situational Awareness
Turns, slow flight, and navigation. Things you already knew about. But perhaps now you will think about them in a new way, so they begin to take on a life of their own in your head. This is the foundation of situational awareness, a quality all experienced pilots speak about but rarely define, because each pilot's situational awareness is his or her own.
As Einstein did, we have been doing thought experiments to train our minds and to come to new understandings about motion. We have been thinking about turns, slow flight, and navigation as examples of integration, where the airplane's velocity vector changes speed or direction and over time changes our position or altitude.
We will go into all this in more detail in later chapters. For now it is enough to follow in the footsteps of Newton and Leibniz and see that we can learn something by looking at the basics in a new way, and that by thinking about things we already know we can begin to develop our own, unique situational awareness.