Navigation

BASIC NAVIGATION

About the author:

The reader has a right to know the qualifications of whom is doing the writing. I soloed in 1966 and received my Commercial license several months later. For the next 20-some years I made my living flying airplanes: flight instructing, charters, mail, commuter airline and ending up as a corporate pilot for the last 15 years or so. In that time I accumulated over 6,000 hours while operating a variety of aircraft ranging from the single-engine Cessna 150 to the four-engine Dehavilland Heron. I retired from aviation in 1988 and now ride in the back like most everyone else- and yes, I am a poor passenger.

Background information:

The act of flying an airplane from "a" to "b" can appear quite daunting to the uninitiated, however in practice it is not all that difficult. As with most things in life, it's easy once you know how to do it. Air navigation can be done by a variety of methods. The purpose of this manual is to explain in simple terms how this is done so that the armchair flight simmer can enjoy his experience more fully.

Navigation can be broken down into two basic groups: visual (VFR), and instrument (IFR). The acronym VFR stands for Visual Flight Rules, IFR stands for Instrument Flight Rules. You should have a good understanding of the flight instruments before you read this tutorial. If you do not, please read the tutorial "How to fly computer flight simulators" before proceeding with this tutorial.

My apologies to my non-American readers. In this tutorial I use the American weights and measures- inches, feet, etc. It is not my intent to be jingoistic, it is the only system that I know.

In addition, I appreciate that the reader would like to "jump right in and fly someplace". Flying and navigating can be complex however, be it in real life, or on a flight simulator. For this reason it is necessary that some basic information be covered first.

Bear with me, we will get there.

Purpose of this tutorial:

At its most basic, one could depart from an airport and see the destination airport right after takeoff. In a more advanced mode your destination lies far off over the horizon.

So, just how do you go out there and find your way "home"? Well, first off you need a map, or "chart" as it is known in aviation. And, just to make life difficult, there is more than one type of chart available. There are "sectionals" that cover a given part of the Earth, "WAC's" that cover a larger area (and therefore require fewer charts to carry along), but because they are smaller, present fewer details than sectional charts do. In addition there are "private issue" charts that are published by companies using data furnished by the appropriate government authorities. Also, there are a variety of instrument charts, ranging from high altitude to SID's and STAR's. And lastly, there are approach plates, the visual and written procedures for landing at a specific airport while using a specific type of approach.

In this, Part 1, I will cover basic visual navigation, getting from "a" to "b", when "b" is over the horizon. Then we will refine our trip using a dispatch form for better organization.

And lastly, this will not be an IFR tutorial. For information on that aspect of flying I refer you to the fine series that was written by Andrew Ayers.

PART 1

Below, is a very simplified, generic rendition of a sectional chart. It differs from actual charts, but will serve our purposes, and will not require the reader to locate and purchase the real thing. I'll reference to this "chart" as I discuss flight planning and preparation. For reference purposes, it is labeled "Chart 1".

Let's go through the items that are depicted on Chart 1.

Notice the small blue runways that illustrate the Crystal Airport. The compass rose represents the Crystal VOR (Very high frequency Omnidirectional Radio). The relationship shows that the VOR is located on the Crystal Airport itself. The top "box" shows the name of the VOR and the frequency, 116.5. The small "d" indicates that the Crystal VOR has DME (Distance Measuring Equipment). The notation "7'E" means that the magnetic variation at this location is seven degrees East of true North. The lower "box" identifies Crystal Airport and shows that the airport is 860 feet above MSL (Mean Sea Level).

A lake.

This represents a town/city named Hopkins.

This represents a Restricted Area. It may, or may not, be "active". Most likely it is used by the military. It is effective from the surface up to 16,000 feet MSL. To find out if it is active or not you would need to contact the controlling authority or ask your weather briefer. From a practical standpoint it would be wise to either avoid it or fly over above 16,000 feet.

This represents a radio/communications tower. The top of the tower is 1,899 feet above MSL.

Another lake.

The distance from the Crystal Airport to the Oxford Airport.

The red line represents the desired course from Crystal to Oxford.

Another VOR. The frequency is 117.3, and once again there is DME associated with the station. The name of this VOR is "Dolly", and the magnetic variation is 8 degrees East of true North.

Distance scale.

Another town. This one is named Eden Prairie.

A lake, with a river coming out of the Southern end.

Another VOR. The frequency is 114.2, and once again there is DME associated with the station. The name of this VOR is "Sparta", and the magnetic variation is 12 degrees East of true North.

The Oxford Airport. Field elevation is 1,200 MSL.

The town of Oxford.

Our aircraft:

The aircraft that we will be using is a Speedster 190, a twin-engine aircraft.

The Speedster 190:

Engines: Continental, normally aspirated (not turbocharged), 250 horsepower.
Propellers: McCauley, constant speed, full feathering, two-bladed, 75 inch diameter.
Passenger capacity (including pilot): Six
Fuel capacity: 100 gallons (600 pounds), maximum
Average fuel burn: 100 pounds per hour
Average fuel burn at climb power: 140 pounds per hour
Average fuel burn at 75% power: 90 pounds per hour
Average cruise speed at 10,000 feet, MSL: 175 knots
All engine rate of climb @ sea level @ max. gross weight: 800 feet per minute
Minimum single-engine control speed (red mark on the airspeed indicator): 80 knots
Recommended safe single-engine speed: 95 knots
Best single-engine angle of climb speed: 100 knots
Best single-engine rate of climb speed (blue mark on the airspeed indicator): 105 knots
Maximum weight in aft baggage compartment: 200 pounds
Empty weight: 3,500 pounds
Maximum gross weight (takeoff): 5,000 pounds
Maximum gross weight (landing): 4,900 pounds

Notice that you cannot fill the Speedster 190 with full passengers, full fuel and full baggage. This is not unusual. Most airplanes require a trade-off in these areas. You must make allowances if you need full fuel for a maximum range trip, or if you intend to carry six people you will not be able to fill up with fuel.

Also note that the maximum landing weight is less than the maximum takeoff weight. This, also, is not unusual. In the case of the Speedster 190 you would have to fly for approximately one hour after a maximum gross weight departure before landing. This would burn off about 100 pounds of fuel, which would meet the landing weight restriction. As an aside, this reduced landing weight is almost always due to landing stress on the gear.

Some airspeed definitions:

Minimum single-engine control speed: Sometimes called Vmc (Velocity, minimum control). With the aircraft at maximum weight, on a "standard day", with the CG at its farthest aft point, with one engine failed and windmilling and the other engine at full power. If the aircraft goes below this airspeed it will start rolling over towards the failed engine, even though full rudder and aileron are applied. If this happens, the pilot must either lower the nose to gain airspeed or decrease power. These are the only two choices that are available to the pilot.

Recommended safe single-engine speed: This is the safest recommended minimum speed for failed engine operations. Keep in mind that operating at the minimum single-engine control speed has no reserve built into it. A little turbulence, or the loss of just one knot of airspeed and the aircraft goes into an uncontrollable roll, and you will most likely contact the earth inverted.

Best single-engine angle of climb speed: This speed will give the aircraft the best angle of climb in the event of engine failure. The rate of climb (feet per minute) will not be the maximum available, but if there are obstacles ahead this is the airspeed you want to use to obtain the maximum amount of clearance.

Best single-engine rate of climb speed: This speed will give the aircraft the best rate of climb, the most feet per minute. If there are no obstacles ahead this is the airspeed that the pilot should us

VFR Trip planning, fuel requirements, etc.:

Basic VFR flight:

Let us make the most basic of VFR flights from Crystal to Oxford. We'll use the Speedbird 190 and take along four of our friends. The weather is clear as a bell, all of the way. You know this because you did a weather briefing prior to departure.

First off let's do a little weight and balance figuring for our proposed trip.

3,500 pounds: empty weight of the Speedbird 190
850 pounds: the weight of your 4 passengers and yourself @ 170 pounds each (1)
250 pounds: fuel on board (2)
4,600 pounds: gross takeoff weight

The Speedbird 190 will be 400 pounds below the maximum gross takeoff weight.

(1) You have a couple of choices here. Either use 170 pounds as an average weight for each passenger, including their baggage. Or, use the actual weight of each passenger and the actual weight of their baggage. Obviously, the easiest way is to use the 170 pound average.

(2) This number is derived as follows: The distance for the trip is 223 miles. Taking into account the slower speeds during climb and approach a guesstimate is made for an average trip airspeed of 150 knots. Dividing 223 miles by 150 knots yields a time of 1.5 hours. With an average fuel burn of 100 pounds per hour, the Speedbird 150 will use 150 pounds of fuel enroute. Add 30 minutes of reserve as a "comfort factor", and another 30 minutes for "the wife and kids". This totals out to 100 pounds of reserve fuel added on to the 150 pounds consumed enroute, for a total of 250 pounds.

OK, now we know that our aircraft is capable of making the trip, letís take a look at how we intend to get from Crystal to Oxford. For this discussion refer to Chart 1.

Our route is roughly 135 degrees from the Crystal Airport. This number is derived by looking at the compass rose for the Crystal VOR and noting that the course line crosses the rose about midway between East (090) and South (180). Adding this 45 degrees to 090 yields 135 degrees as our departure heading.

We cannot fly direct from Crystal to Oxford because the restricted airspace, R-207, lies across the direct route. This will require that we fly a dog-leg course.

After departure from Crystal turn to a heading of 135 degrees and fly that heading as you climb out. Keep an eye out of the right side of the aircraft for the lake that lies about 15 miles Southeast- this is our first checkpoint. Our aircraft should pass directly over the small peninsula that extends from the East side of the lake. Adjust the heading of the aircraft as necessary to cross this point. As the aircraft cross the peninsula resume the 135 degree heading.

Now that we have crossed our first checkpoint start looking off to the left side of the aircraft for the town of Hopkins. Although not as accurate a checkpoint as the peninsula was, fly the aircraft so Hopkins passes off to the left side by about 7 miles. Continuing on, be looking out the windshield for the large lake that is south of the restricted area. This segment of our trip is the most critical as we do not want to wander into the R-207 airspace.

Restricted airspace, and its big brother prohibited airspace, are not things to take lightly. Prohibited airspace is usually reserved for things like a president or prime ministerís home or "office". Restricted airspace usually involves the military.

As the lake nears we adjust the aircrafts heading so that we cross just South of the Northwest tip of the lake. In addition, there is a radio or TV tower just off to our right. However, towers are extremely difficult to see from the air and don't make for very a good visual checkpoint.

After crossing the lakes tip we turn to our new heading of about 120 degrees for Oxford. Our next visual checkpoint is the town of Eden Prairie. Adjust the aircraft heading so that it passes just off to the right side. Next up is Lake Minnetonka and the small river that empties out of the Southeast corner. We should pass just to the left of the small island that is in the river- adjust the aircrafts heading if necessary.

Now we look ahead for the city of Oxford. Once the city appears, bring your vision scan to the Northwest side of the city and look for the airport. Once the field is in sight, start your descent for landing.

And there you go, you just flew from one airport to another. Kinda shaky wasn't it? Here you were grinding around at 175 knots looking for objects on the ground without having a clue as to when they should appear. In addition, the headings were just a guess on your part. You thought that you had enough fuel for the trip, but had no way to verify that information as the trip went along. So, while effective, it is not the best way to navigate an aircraft.

A better plan:

There must be a better way, and of course there is. First off I have to introduce a tool that is called a "plotter".

Plotters vary in size and format, but this is a fair representation of one. Notice that there is a protractor on the top. This protractor is marked off in 360 degree segments. The horizontal lines are for orientation with your course, and also have various scales so that the device can be used on a variety of charts that may utilize different mileage scales.

Now let's apply this new tool.

First off we would like a more accurate course heading out of Crystal than our previous guesstimate. Lay the plotter over the Crystal VOR. Center the protractor over the compass rose and align the horizontal lines with the course that is drawn on the chart.

Reading from the protractor we can see that our course is 132 degrees.

Next we want to measure the distance to our first check point, the peninsula on the lake that is Southeast of the airport. Using a pen or pencil we make a mark on the chart where the course line crosses the point of land. Next we line up the appropriate scale on the plotter to measure the distance from the Crystal Airport to the checkpoint.

Reading the scale on the plotter we see that the distance to our first checkpoint is 23 nautical miles.

Our next measurement will be to determine the distance to our next checkpoint, the tip of the next lake. This will require moving the plotter along the course line and adding up the two distances.

The distance to our next checkpoint measures off as 64 miles. Also, at this checkpoint our heading will make a change as we are now clear of R-207.

The plotter is positioned over the nearest VOR to the airport, in this case the Sparta VOR. Align the parallel lines on the plotter while the protractor is centered on the VOR symbol. This yields a reading of 124 degrees- our heading from our last checkpoint, and also our heading to the Oxford Airport.

Next, we need the distance from the "turn checkpoint" to our "island checkpoint". This is accomplished as before by laying the plotter down on the course and adding up the measurements to get the total distance. In this case it is 82 miles.

Our last step is to measure the distance from this last checkpoint to the Oxford Airport. The distance reading is 54 miles We already have our inbound heading from the measurement that we did earlier- 124 degrees.

Now we are able to establish a more refined VFR navigation flight plan.

23 miles: Distance from the Crystal Airport to checkpoint #1 (heading 132 degrees)
64 miles: Distance from checkpoint #1 to checkpoint #2 (heading 132 degrees)
82 miles: Distance from checkpoint #2 to checkpoint #3 (heading 124 degrees)
54 miles: Distance from checkpoint #3 to the Oxford Airport (heading 124 degrees)
223 miles: Total distance for the flight

Let's refine this a little farther and come up with some time estimates for each of the legs. Then we will take this information and fill out a flight log for our trip.

Leg 1, departure, climb to 5,500 feet, cruise (23 miles):

Time: Figuring in the takeoff, and time to climb from 860 feet msl to 5,500 feet msl at an average climb rate of 800 feet per minute yields a time of 5.8 minutes- round this off to 6 minutes. Flying for 6 minutes at climb airspeed of 105 knots will cover a distance of 10.5 miles- round this off to 11 miles. At cruise speed we have 12 miles left to go on this leg (23 miles, less the 11 miles traveled during the climb). Eleven miles at a cruise speed of 175 knots is 3.7 minutes- round this off to 4 minutes.

Now we have a time estimate for our first leg: 10 minutes

Fuel: Six minutes at takeoff and climb power yields a fuel burn of 14 pounds. (140 pph x 6 minutes). Four minutes at cruise power yields a fuel burn of 6 pounds. (90 pph x 4 minutes).

Now we have a fuel burn estimate for our first leg: 20 pounds.

Leg 2, cruise at 5,500 feet (64 miles):

Time: Flying along at 175 knots it will take 22 minutes to cover the distance of 64 miles.

Fuel: Twenty two minutes at 90 pph yields a fuel burn of 33 pounds for the leg.

Leg 3, cruise at 5,500 feet (82 miles):

Time: Flying along at 175 knots it will take 28 minutes to cover the distance of 82 miles.

Fuel: Twenty eight minutes at 90 pph yields a fuel burn of 42 pounds for the leg.

Leg 4, cruise at 5,500 feet, descend and land (54 miles):

Time: Flying along at 175 knots it will take 19 minutes to cover the distance of 54 miles.

Fuel: Nineteen minutes at 90 pph yields a fuel burn of 29 pounds for the leg.

Total estimated time enroute: 1 hour, 19 minutes

Total estimated fuel burn enroute: 124 pounds

Now we have our estimated times and fuel burns for each leg. Prior to this we had determined our headings for each leg. Letís put this information onto a form so that we can refer to these useful numbers enroute.

TIME OF DEPARTURE: time that the wheels leave the ground
EST. TIME ENROUTE: your flight planning estimate
TIME OF ARRIVAL (est./actual): add the estimated time enroute to the ìwheels upî time for this figure
TOTAL FUEL ON BOARD: as appropriate
TOTAL FUEL REQUIRED: fuel required to meet VFR or IFR standards
POSITION: departure airport, checkpoint, waypoint, VOR, destination, etc.
STATION / FREQ.: frequency of the appropriate navigational aid
DIST.: the distance for the leg
EST. LEG TIME: estimate for the amount of time to fly this leg
TIMES: just a header for the column
ETA: estimated time of arrival at next point
ACTUAL: the actual time of arrival at the next point
TIME STATUS, + / -: based on your ETA for the leg, amount of time that you arrive early, or late
EST. FUEL BURN: estimated amount of fuel used for the leg
FUEL REMAINING: ESTIMATED: amount your pre-takeoff projection indicates/ ACTUAL: actual amount
FUEL STATUS, + / -: amount of fuel over, or under your estimate
REMARKS: any appropriate comments you wish to write down

Now let's go back to our last trip and use this "dispatch form".

All of the information that is filled out on the above dispatch form can be done before the trip.

Using the dispatch form on the Crystal to Oxford flight:

Departing Crystal we lift-off at 11:15am. Jot this time down in the "time of departure" box and turn to your heading of 132 degrees. When you have time, enter "11:25" in the "ETA" box for the first leg. Still using our visual checkpoints as before, we arrive over our first one at 11:23, two minutes ahead of schedule. Write down the time "11:23" in the "actual" box, and write the notation "-2" in the "time status" box. Write down "11:45" in the "ETA" box for the next checkpoint. Note the fuel remaining and write it down in the "actual" box under the "fuel remaining" column. For the sake of this example, let's say that there is 240 pounds remaining. Enter the number "240" in the "actual" box, just below the number 230. Next to that, in the "Fuel Status" box, enter a "+10" indicating that you have 10 pounds more fuel than you had estimated to have at this point in the flight.

Your form would look like this (with your new entries in red):

Continuing along your flight you make the appropriate entries as you cross over each checkpoint. Is this a lot of work? You bet it is! Does it create a lot of "head down" time as you make entries? It can, but if you do it properly, thinking about what numbers you are going to write down and where, it can be done in an expeditious manner.

The whole point of this exercise is to remove as many unknowns a possible. Also, it has the ability to let you know well in advance if a long trip is viable, long before you get near your destination and are running low on fuel.

Let's say that you are taking your trusty Speedbird 190 on an extended trip, one that will push the aircraft to itís maximum range. Your dispatch form for this trip might comprise twenty checkpoints or more. After the first few entries you will be able to see a trend developing. Is each leg taking longer than you had estimated? Does the "plus or minus" entry in the "Time Status" box keep increasing? Do the entries in the "Fuel Status" box continue to increase in a "negative number"? Well, you have problems.

But you have made this observation at the early stage of the trip when you can take appropriate action, like a fuel stop that you hadn't planned on before. The point is that you will know your status early into the trip, not when you are "sucking fumes" with the weather going down all around you.

Aviation can be fraught with surprises. Anything that you can do as a pilot to eliminate as many of them as possible will make your task that much easier- and safer.

This form, or a variation of it can be used in "real: or virtual aviation. The one that I personally used for my corporate work had this information plus a passenger manifest. On the other side I drew up a weather form for listing forecasts, hourly obsevations, ATIS, winds aloft and other useful information.

This ends the first part of "Basic Navigation". In the next part we will discuss using VOR's for VFR navigation.

PART 2

In this, Part 2, I will cover basic visual navigation using the VOR's (VORTAC's) for a little more refined navigation. The established airways are there for both VFR and IFR operations. Right off of the bat you can see that there is a lot of information presented that will save you time and effort in your preflight planning. Headings and distances are given. In addition, there is airway altitude information for safe obstruction clearance.

There is one thing that must be kept in mind, however, when "flying the airways". Because you are on an "airial hiway" there will be more traffic- both VFR and IFR. The VFR traffic will be flying by the "odd or even, plus 500" rules, and the IFR traffic will be flying by the "odd or even" rules.

VFR:

If your magnetic _course_ (not heading) is from 0 to 179 degrees, and you are more than 3,000 feet above the surface, you must fly at "odd thousands" plus 500 feet. This means 3500, 5500, 7500 etc.

If your magnetic _course_ (not heading) is from 180 to 359 degrees, and you are more than 3,000 feet above the surface, you must fly at "even thousands" plus 500 feet. This means 4500, 6500, 8500 etc.

IFR:

IFR traffic flies at "oddî or ìeven", but without the "plus 500 feet". So, there is only 500 foot of guaranteed separation between you as a VFR flight, and the IFR traffic that is also using the airway. Also, keep in mind that if your aircraft is faster than the average bear, you may over-take slower traffic at the same cruising altitude. Conversely, if you are a slow cruiser, you may be over-taken by faster traffic. The bottom line is that you want to keep an eye out for traffic, of both varieties.

Chart 2:

Below, is a very simplified, generic rendition of a chart. It differs from actual charts, but will serve our purposes, and will not require the reader to locate and purchase the real thing. I'll reference to this "chart" as I discuss flight planning and preparation. For reference purposes, it is labeled "Chart 2".

Notice that if varies considerably from our previous chart, "Chart 1". Now we have the airway system depicted, along with some limited terrain information.
Let's take a look at some of this new information.

These are IFR minimum obstacle clearance altitudes, in MSL. "13o" stands for 13,000 feet, "16o" stands for 16,000 feet, and so on. If our sample chart were real, there would be some very high terrain indeed just to the North of our route.

A high altitude airway, in this case route J-13. The high altitude airways go into effect from 18,000 feet and up. They are shown on low-altitude charts for orientation. If you were departing Crystal Airport and flying a high altitude capable aircraft, you could file "Crystal, J-55, Spartaî, and so on. On the reverse, if you were landing at Crystal from a trip originating to the East, you could use Sparta as your transition VOR and file "....J-55 Sparta, V-58 Crystal...". Although more likely you would file J-55 right to Crystal and expect vectors for lower altitude from ATC.

A low altitude (17,500 and below) "Victor Airway"- in this case V-24. The airway is made up of the 125 degree radial from the Dolly VOR, and the radial from the next VOR, which is not shown in this example. The "7200" is the minimum obstruction altitude for IFR flight, but for the VFR pilot gives important information for terrain clearance. In this case, flying V-24, 7,500 feet and 8,500 feet should be considered as your minimum visual altitudes.

This is the distance on the airway between VOR's, in this case it is 155 nautical miles from Dolly to the next VOR.

An intersection. In this case, named "Ralph". The intersection is formed by the 055 degree radial from the Dolly VOR, and the 132 degree radial from the Crystal VOR.

The "87" is the distance from the Crystal VOR to the Ralph intersection.

So now we can see two ways to determine the Ralph intersection.

Centered on the 213 degree radial from the Crystal VOR, we would be at the Ralph intersection:
1. At 87 miles, DME from the Crystal VOR, or
2. When we cross the 055 degree radial from the Dolly VOR

FLYING FROM CRYSTAL TO OXFORD USING THE AIRWAYS

Now let's make our trip again from the Crystal Airport to the Oxford Airport, but this time we'll use the established airways. Once again we drag out our dispatch form and plan our route.

Leg 1, departure, climb to 5,500 feet, cruise (87 miles):

As long as the Crystal VOR is conveniently located on the airport itself, we simply have to set our Nav. one VOR to the Crystal VOR frequency of 116.5 and set the OBS to the outbound radial, 132 degrees. The DME will read somewhere in the "tenths" to the VOR while we are on the ground.

After departure we will fly headings as necessary to keep the radial centered in the Nav. one display. At 87 miles DME from the Crystal VOR we are at the Ralph intersection. This can be verified by tuning VOR two to the Dolly VOR and selecting the 055 degree radial. When the CDI centers in the display of VOR two we are at the Ralph intersection. At Ralph we turn to a new heading of 129 degrees and track inbound on the 309 degree radial (the reciprocal of the 129 degree radial) of the Sparta VOR.

Time: Figuring in the takeoff, and time to climb from 860 feet msl to 5,500 feet msl at an average climb rate of 800 feet per minute yields a time of 5.8 minutes- round this off to 6 minutes. Flying for 6 minutes at climb airspeed of 105 knots will cover a distance of 10.5 miles- round this off to 11 miles. At cruise speed we have 76 miles left to go on this leg (87 miles, less the 11 miles traveled during the climb). Seventy six miles at a cruise speed of 175 knots is 26 minutes.

Now we have a time estimate for our first leg: 32 minutes

Fuel: Six minutes at takeoff and climb power yields a fuel burn of 14 pounds. (140 pph x 6 minutes). Twenty six minutes at cruise power yields a fuel burn of 39 pounds. (90 pph x 26 minutes).

Now we have a fuel burn estimate for our first leg: 53 pounds.

Leg 2, cruise at 5,500 feet (126 miles):

Time: Flying along at 175 knots it will take 44 minutes to cover the distance of 126 miles.

Fuel: Forty four minutes at 90 pph yields a fuel burn of 66 pounds for the leg.

Leg 3, descend and land (10 miles):

Time: Descending and landing at our destination airport (Oxford) at an average airspeed ("Kentucky windage") of 155 knots, it will take 5 minutes to cover the distance of 10 miles.

Fuel: Five minutes at 90 pph yields a fuel burn of 8 pounds for the leg.

TOTALS FOR OUR TRIP:

Total estimated time enroute: 1 hour, 21 minutes

Total estimated fuel burn enroute: 127 pounds

Notice how much easier it was to fill out our dispatch form with the information that was already available from this type of chart. The down side of using these charts for VFR navigation is that very little surface information is given. Towns, railroads, water towers, lakes (except for the larger ones) are not shown.

FLYING FROM CRYSTAL TO OXFORD USING AREA NAVIGATION (RNAV):

Area navigation (RNAV) is a convenient and relatively inexpensive form of navigation that allows a pilot to fly in a direct line or, on a longer trip, a great circle route. It is not as user friendly as GPS, which is rapidly taking over this facet of aviation navigation.

When using RNAV, you are in effect creating a "phantom VOR" by electronically moving an existing for to a location of your choice. Let's set up an example to use for more explanation.

In our above example we wish to fly from "A" to "B". Notice that at our three enroute checkpoints the "cardinal" radials have been chosen. "Cardinal" radials are OOO, 090, 180 and 270. While any radial can be chosen, picking the cardinal ones makes it easier to layout with your plotter as they are clearly defined on the charts. In a perfect world, you would use the radial that crosses your flight path at a ninety degree angle, as this yields a more precise definition of the point in space. However, the above usage is more than acceptable.

HOW IT WORKS:

There are three basic windows in an RNAV unit.

1. The "frequency window", used to tune in the selected VOR. In some installations,
this window is not present. By selecting "RNAV" from the radio menu, the RNAV unit
automatically is fed the information from radio one or two as predetermined at the
time of radio installation.

2. The "radial window", used to select the desired radial from the VOR in use.

3. The "distance window", used to set the distance you wish to "move" the VOR.

OK, I admit that this may be a little confusing right now, but trust me- RNAV really is a simple concept. For this example, our RNAV unit is fed input from radio number one. By placing the switch on the unit to "RNAV" it will be fed the VOR and DME information from our Nav. one radio.

Before departure, during our flight planning stageî, we have used our now familiar plotter and determined our course heading for each leg, the distance for each leg, and the desired radial and distance for our "waypoints".

So, here we are on the ground at "A" in our trusty Speedbird 190 wanting to fly this fancy RNAV direct route to "B". How do we go about this? First, tune Nav. 1 to the frequency of the VOR that will form our first waypoint, Shorty, 117.4. Next, dial in the radial, 000 degrees, and the distance, 021 miles. Turn the OBS on your nav. 1 display to 120 degrees. Also, for orientation sakes, set your heading bug to the course- 120 degrees. (We're going to use a no-wind situation here.)

After departure, turn to your heading of 120 degrees. Assuming that the Shorty VOR is being received, your display will show you as on course, the "TO / FRO"î arrow will be in the "TO" position, and the display will show 12 miles. As far as your readouts are concerned, the Shorty VOR is at your waypoint. As you close on the waypoint, the readout will "count-down" to zero, the "TO / FROM" flag will flip to the "FROM" position, and the mileage will begin counting up again as you cross the waypoint.

The OBS setting remains at 120 degrees as we track outbound from our waypoint. When you have a stable signal from the Flandar VOR, dial in the radial, 180 degrees, and the distance, 049 miles in the RNAV unit. Also, using the OBS set your course to 121 degrees. The displayed mileage will start counting down to our next waypoint, and the "TO / FROM" indicator will display "TO". Once again the mileage counts down until we reach our next waypoint.

Finally, as we near our landing site, "B", we tune in the Billy VOR and the 048 degree @ 023 coordinates. The display will show our distance from the center of the airport, and the distance will count down accordingly.

Pretty nifty, huh? With RNAV you can "place a VOR" anywhere you want to- over an Outer Marker for orientation during an ILS- with distance display to the Marker. Or, you can set up your holding pattern in a more understandable display. In short, RNAV not only saves you time and money by permitting direct routing flights, it is a great orientation device.

GPS:

I regret that the writer has no working knowledge of GPS, so that aspect of our navigation primer will have to be left out- my apologies.

I hope that this has proven helpful to the reader.

This tutorial is available on a CD

This tutorial, along with additional content, is available on a CD. Click here for more information.

Thank you.

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