Airienteering with 13MIKE

by Fred J. Calfior and Douglas W. Miller


Overview -

Within the AirLegs, you may be given turns to a heading, or asked to intercept and track inbound or outbound on a certain radial, or Victor Airway. The power settings you use for cruise, the airspeeds you fly, are all left to your discretion. For the most part, when asked to climb or descend to a certain altitude, it's to your advantage to do so expeditiously. Do not bide your time by casually changing altitudes!

An AirLeg may end when you are overhead a specific landmark which is identified only by your Terminal Area chart. By mapping its radial and DME from a navigational facility, you can determine when you have arrived overhead that point.

Appendix A in the back of this book contains all the Terminal Area charts that you will need for each scenario. A recommended practice is to draw each AirLeg as you fly it, and label that AirLeg on the chart, thereby keeping track of your path. The charts in this book are for a specific time period, and are not valid for any real flights that you might be thinking about flying yourself. Due to several comments, it might be worth your while to pick up a separate chart for yourself at your local airport, so that you can spread it out and move about more freely. Most likely the chart you acquire will be a later version, which will have some changes in it. So always compare your chart with what's given in this book. Where there's a difference, the chart in this book is the authority.

Types of navigation -

Within the scope of Airienteering with “13MIKE”. there are three forms of navigation used. Dead reckoning, pilotage, and radio navigation. Radio navigation is simply using a VOR radial, for instance, and going outbound or inbound off of that radial, as well as making intercepts which will put you on a desired radial.

Dead reckoning is the art of computing groundspeeds, headings, courses, winds, along with a few other performance details, and putting them together to help you arrive at a destination point properly.

Pilotage is flying from one visual landmark to another, such as from a water tank to that railroad track up ahead, then to the river further ahead, etc.

Where am I? -

To competently arrive at a desired fix, you must first know where you are currently. There are a variety of methods which will tell you your present position in the air. Of course, if you see a landmark underneath you and it corresponds to what you see on the VFR Terminal Area chart, then you can't get a better pinpoint fix than that! But with the default scenery of Microsoft Flight Simulator, that will be a luxury and exception, rather than the normative situation.

Using radial and distance measurements from a VOR facility will be your most frequently used method of pinpointing your position. Tune and identify the VOR facility you want to use, to make sure you've got the right one. Then center the course deviation indicator (CDI) needle, and be sure to have a 'FROM' displayed on the VOR face. Read what your omni-bearing selector says, and that is your radial from the station. On your VFR Terminal Area chart, draw a line from that VOR facility along that radial, and now you need to determine where on that line you are positioned.

Acquire the DME off of that VOR facility, and your fix is glued in place! If 10.0 DME, then measure along the line to 10 nautical miles, using your measurement scale given, and put a dot at that fix. That is where you are!

Measuring courses -

There are two courses which you will probably be interested in measuring. They are true courses and magnetic courses. The difference between the two is that true courses are measured from the geographic north pole, whereas magnetic courses are measured from the magnetic north pole. The distance between the two poles is approximately 1300 miles! Your true course is determined by a line drawn from you to the geographic north pole. Your magnetic course is determined by a line drawn from you to the magnetic north pole. The angle between those two lines is called the magnetic variation. Knowing the variation of your geographic area, you can easily convert a true course to a magnetic course, or a magnetic course to a true course.

When wanting to determine a true course from your current position to your desired position, draw a line between the two points. Then take a navigation plotter and line it up along the drawn line with the middle hole on the line. Place the hole on a line of longitude, and read the true course that is lined up on the longitude vertical line. Make sure that you are choosing the right course, because the two available choices are 180 degrees different. If your track is going eastwards, then you choose the easterly of the two courses. If going westwards, then of course, choose the westerly of the two courses. If your course line is more north-ish and south-ish, then do the same thing, but read your courses off of the inner scale of your plotter from a line of latitude.

If you want to know what the corresponding magnetic course would be for that true course, then find the closest variation line, and apply that variation to your true course. A phrase which will help you to remember how the correction is applied is “East is least and West is best when going from true to magnetic”. If your variation is 15 degrees East, and the true course is 270 degrees, then “East is least…when going from true to magnetic”, which means that a 15 degree East variation will make the magnetic course less than the true course by 15 degrees. 270 degrees true equals 255 degrees magnetic! Simple!

Take that same line that you've drawn, and place your navigation plotter over it as before. Now move the plotter in a parallel direction until it is centered over a magnetic compass rose on your VFR Terminal Area chart. Read the magnetic course that your plotter intersects on the compass rose, and you now instantaneously have a magnetic course! That's because the compass roses on your Terminal Area charts are oriented to magnetic north, which is why you'll notice them slightly skewed from straight up and down.

Victor Airways -

Victor airways are highways in the skies, sort of like German Autobahns or expressways or turnpikes or interstate highways! You'll see them depicted all over the place on your VFR Terminal Area charts, with an outbound magnetic course from a VOR facility, and an inbound magnetic course to a VOR facility at its other end. To fly those Victor airways, which you will do quite often in this book, be aware of your winds and supply whatever correction is necessary to keep the CDI needle centered. Do that, and you'll always be where you are supposed to be, so that your answers will match those in the back of the book! Oh boy!

Track, course, and heading -

Let's distinguish between these three critters, because it is vitally important to know what they mean in relationship to one another. When you know where you are, and you know where you want to go, then the straight line between those two points is a course. Measuring that line from a plotter oriented to a line of longitude makes it a true course. Measuring that line from a compass rose makes it a magnetic course.

A heading is where you need to point your nose so that the airplane will travel along that course line. The difference between a heading and a course is called the wind correction angle. If you fly a heading equal to the course, then winds will veer you off of your course line and you will miss your desired mark.

A track is a line that your aircraft is actually following. If you are applying the right corrections for wind, then your track will be the same as your course, because you have applied the proper heading. So let's talk about how to apply the right corrections!

Correcting for winds -

This is a biggee! I will show you two methods of wind correction, so that when going from Point A to Point B, your heading will get you to Point B consistently. First, the harder way - even though both methods are compulsory and easy to master.

A wind triangle is a graphic representation of the effect of wind on a flight. To solve a wind triangle problem, you must know number one - the wind speed and direction. Number two - the desired true course direction. And number three - the airplane's true airspeed. Armed with these three items, you can now calculate your ground speed and true heading.

          Step One

Right on your chart, draw your straight line from where you are to where you want to go. Since all three winds settings for this book are taken from the surface wind dialog boxes, then the winds are magnetic.

          Step Two

Now draw the wind direction line at the correct angle, through the course line you just drew, and starting at the 'where you are' point. For instance, in the third scenario, your wind is 300 degrees at 12 knots. So since the winds are coming from 300 degrees magnetic, make sure that you draw your wind line in a direction heading towards 120 degrees, which is where the wind is going. The length of that line needs to be one hour's worth, so 12 miles. If you were a balloon (well, if you were in a balloon!) drifting with the wind, in one hour's time, your position would be at the end of that wind line!

          Step Three

To figure out your true airspeed, the easiest thing I can tell you at this point is to simply go with your indicated airspeed. That will put you, as far as the Cessna 182 RG aircraft is concerned, within the ballpark! If you want to get high falutin' and fancy, then use the 2% rule. That is, increase your indicated airspeed by 2% per thousand feet mean sea level that you are flying. As an example, if your indicated airspeed is 140 knots and your altitude is 5,000 feet, then 2% per thousand means that you will increase your 140 knots by 10% (5 X 2%), which gives you a true airspeed of 154 knots.

Now scribe an arc which will intercept your course line 154 miles (one hour's travel) away from the end of your wind line. Connect the end of the wind line to that intersection point, and the third side of your wind triangle is drawn.

          Step Four

Using your plotter, determine the magnetic course of that third line. That is the heading that you will need to fly to get to the point that you desire, based upon the existing winds.

Now let me clarify a point. Whether you use true courses, or magnetic courses, does not make any difference. But if you use true courses, then make sure that everything you're doing is using a true reference. If you use magnetic courses, then make sure that everything you're doing is using a magnetic reference. In other words, as I say in my navigation classes, “Keep all your apples in one basket, and keep all your oranges in another basket, and never the twain shall meet!”

Because your winds for these Flight Simulator scenarios are using a magnetic reference, you might want to avoid any confusion by always working with magnetic courses. Or if your little old heart desires, apply the variation to the winds to get true winds, and use true courses. Whatever lifts your wonderful heart to heights of ecstasy!

The second method of determining the proper heading to your desired point is to use a mechanical computer, like an E6B or CR type, or a flight navigation electronic computer. Either way, without me getting into any of the details, you will be computing a wind correction angle (WCA), which is the difference between your course and your heading, and supply that correction to your drawn track. If you have one or the other of those, go for it!

Identification of intersections and landmarks -

You will be told many times to fly to a specific intersection fix, visual check point, or landmark. After you have drawn your lines, record what that point's radial and DME is from a certain VOR facility. Now, as you're flying along, you periodically may want to check your position by a radial/DME fix. If that fix puts you on the line you're supposed to be on, then life is marvelous! If your fix is offset from the line, then correct your heading so that you can get back on your desired course line. I call this procedure “benchmarking”, which is comparing your actual position to your desired position!

Let me reiterate once again! Do not rely upon the position of any landmark that you see on your 'out of window' view of Microsoft Flight Simulator. Always go to landmark or point's location indicated by the Terminal Area chart, because that's the reference used in writing this book.

Many times, you will be asked to 'Press P to pause the simulation' when you are abeam a certain landmark or point. Well, from that point, draw a line perpendicular to your course line, and it's at that intersection on your course line that you will be abeam the point.

VFR Terminal Area Chart Interpretation -

Interpreting symbols on the Terminal Area Charts will be one of your biggest tasks in this book. Visual check points are flagged. What does a railroad look like? How about mines and quarries, or dams, golf courses, hospitals, single and double obstructions, marine radiobeacons, racetracks and heliports? What kind of airspace are you flying over? Is it Class B, or Class C, or Class D? What are their floors and ceilings? That DME band - is it for San Francisco or Oakland VOR? Kennedy or La Guardia? What is the length of that runway, and is it lighted all the time or just part time? These are some of the questions that become important to answer when navigating from one point to another, and relying upon your Terminal Area chart. Each chart carries a wealth of information that can save your life! What is the lowest altitude that I can safely navigate at for the specific area I'm flying? Is that an IFR departure route or an arrival route? What is the above ground level height of that tower that seems pretty close to me? Your legend pages in appendix B will guide you to those answers as you work and work and work your charts, navigating with Airienteering wisdom.

In a Terminal Area chart you cannot use the same mileage scale as you would with a VFR sectional chart. On the sectional chart one degree of latitude equals one nautical mile, not so on a Terminal Area chart. Therefore, you are supplied with a mileage scale on the bottom of the legend page in appendix B. Notice that there are three scales available. They are 'nautical miles', 'statute miles', and 'kilometers'. The only one you are concerned about is the 'nautical miles'. When measuring distances, do not believe that you are right the first time! Once the distance is measured, measure it again to verify that the plotter did not slip, or that you inadvertently measured off of the wrong scale. The left side of the mileage scales are subdivided into units of one mile going right to left, zero to five. To the right of zero, the subdivision goes to units of five miles. Therefore, when trying to measure an about 13 nautical mile course, place one end of your plotter on the '10', so that the other end will be able to show you whether it is 12.5, or 13.0, or 13.5 nautical miles, etc.

Flying the Arc -

As a rule of thumb, when turning approximately 90 degrees to intercept an arc, lead the turn by about .6 or .7 nautical miles on your DME display. It obviously will change based upon how slow or fast you are cruising, but that average will work fine, mostly, always! (Good English, huh?!)

Prior to your turn to intercept, find out what radial you are on by centering the CDI needle with a 'FROM' indication. Then turn left or right, clockwise or counterclockwise, so that your initial heading on the arc is 90 degrees from that radial. Check your DME to determine whether your heading is good to hold the arc, or whether a correction is necessary. Another standard rule of thumb is that for every 0.1 nautical mile inside of an arc, correct 5 degrees. For every 0.1 nautical mile outside of an arc, correct 10 degrees.

Once established on the arc, adjust the OBS to the next 10 degree radial 'FROM' the station. Turn the corresponding 10 degrees to match that OBS setting by a 90 degree difference. When the CDI needle centers, adjust the OBS to the following 10 degree radial 'FROM' the station, and so on and so forth. Don't forget to correct aggressively.

This is a busy time of flying, especially when corrections become prevalent. The key is to always have a picture in your mind as to where you are in relationship to the arc, and never be satisfied with being even slightly off kilter. Nail down that 7, or 10, or 15 DME arc until it's time to turn aside.

Airspace Altitudes -

The altitudes that are assigned to you throughout all the AirLegs are predominantly below or above the controlled airspace depicted. At times, you may notice that it appears that you are busting the altitude limitations for the controlled airspace you're in. Well, most likely, it's because you are! And pretty soon thereafter, you'll probably be advised that you've reached a dead end! In actuality, you will be in communication with the controlling ATC facility, who might give you clearance through a controlled airspace within its altitude boundaries. We have tried to keep you flying legally all throughout the scenarios.

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