When planning a cross country flight of any distance, the pilot is required by Federal Aviation Regulations to have knowledge of the destination airport, fuel requirements, estimated time enroute, weather expected along the route and destination, and any other information which may affect the safety of the flight. The pilot should get a thorough weather briefing from a Flight Service Station (FSS), and the filing of a flight plan for VFR flight is strongly recommended.
This section will cover the time, distance, groundspeed, heading, and fuel required aspects of the flight planning process.
Basic ParametersThe planning log must address several factors:
The pilot should determine the type of navigation to be used; Pilotage, VOR and/or Victor Airways, LORAN, GPS, etc. From that information, the pilot should establish checkpoints over which the flight is to pass. They may be prominent landmarks, VOR's, RNAV, LORAN or GPs waypoints. It is suggested for small slow speed aircraft that these checkpoints be within reasonable distances, say 50 nm or so. Distances shorter than this requires a lot of record keeping for long flights. Distances much longer than this does not allow the pilot to verify actual performance versus the plan sufficiently often enough. Generally a checkpoint every 30-40 minutes is a suitable procedure for the experienced pilot.The pilot should plot the Course of Flight by drawing lines on the chart from checkpoint to checkpoint. It's like drawing your roadway in the sky which you plan to follow. These checkpoints should be written on the flight planning log in the Check Point column of your planning log.
An example flight is illustrated below. The flight is a simple one which a beginning student may be asked to fly. It is a triangular course, from SVH, LEX, 3N8, and back to SVH. You will note later that the wind will have a different effect on ground speed and headings for each leg. Note: This flight will be used as the basis for planning a simple flight and the associated flight planning log.
You will note that there are a number of items of information whick the pilot must consider:
See -- Cruise Performance for an example table.
Filling out the Planning Log
Winds aloft are forecast by the Weather Bureau for numerous regions in the U.S. At the levels at which small aircraft fly, the forecasts will give wind direction and velocity in Kts. for 3, 9, and 12 thousand feet. You use the wind forecast nearest the altitude which you plan to fly to calculate the wind drift you expect to encounter. This calculation also derives an estimated Ground Speed which you will use in further calculations. The Wind Correction Calculations are covered later.
True Airspeed and Fuel Consumption
Consult the Pilot Operating Handbook for the aircraft to be flown to determine the power setting you plan to use at the planned flight altitude. See -- Cruise Performance for an example table. From the cruise performance table for the aircraft you should be able to derive estimated TAS and Fuel Consumption in gph. You will later use this TAS to calculate both the estimated WCA and Ground Speed. You will use the fuel consumption figure (gph) to calculate the estimated fuel consumption for each leg.
Course Planning InformationIdentify each checkpoint on the chart in some way. It may be a number, an airport name, a VOR name, or city, etc. Write the identification of the each checkpoint in the CHK PT column of the log. Note that the checkpoint lines are not aligned with the other lines in the blank log form shown above.
In our example, our checkpoints are:
Measure the distance as shown in Measuring the distance . Enter the distance in Nautical Miles (preferred) in the DIST column for each leg.
Using the plotter, measure the TC for each leg, using the example in - Measuring the course example. True Course is always measured in relation to a Longitude Line on the chart ( i.e. relative to True North). Enter the TC for each leg in the TC Column.
Compensating for WindIn order to keep being blown "off course" by the wind, you probably will have to maintain a heading to either left or right of course to stay on track(TC). This requires that you calculate a Wind Correction Angle (WCA) in order to stay on track.
You can use a manual or electronic E6B Flight computer to compute the WCA. Obviously, when you are riding in a moving air mass, the wind will tend to drift you "Off Course" from your intended ground track.
A Graphical Illustration of WCAShown below is a graphical illustration of calculating WCA.
Normally the pilot will use either a manual or electronic E6B Flight Computer to solve WCA problems. Consult your E6B computer manual for problem solution methods.
WCA for the Example FlightThe example flight from SVH, LEX, 3N8, SVH is shown below. The wind aloft for this problem is 270 degrees true at 35 knots. On your planning chart, add and subtract the WCA's to the TC's to fill out the TH column.
Correcting for Magnetic Variation
As a refresher on Magnetic variation, see Magnetic Variation . True North and Magnetic North are not at the same location on the earth. In the eastern US, the Magnetic North Pole is west (left facing north) of the True North pole. The AGONIC LINE (where true and magnetic north are the same) runs from upper eastern Wisconsin, diagonally Southeastward through the central South Carolina coast. The difference between the True and Magnetic Norths is called Magnetic Variation (VAR). It is called Westerly Variation east of the agonic line; i.e. Magnetic north is west of True North. It is called Easterly Variation west of the agonic line.
To convert from TH to Magnetic Heading (MH), Add Westerly VAR, Subtract Easterly VAR. The variation is shown on the Aeronautical Charts as dashed magenta lines, running from the top to the bottom of the chart. They will be labeled 6°W, 10°E, etc.
In your planning log, write the magnetic variation down in the VAR column (denoted by the *). Add or Subtract the VAR (W = +, E = -) to the TH to get the Magnetic Heading (MH) values. This portion of the example SVH, LEX, 3N8, SVH flight is shown below. The flight is totally within a region where the Magnetic Variation is 6 degrees WEST.
Distance and Time
As a by-product of the wind triangle calculations to arrive at a Magnetic Heading for each leg, you also found the Ground Speed for each leg. Using this GS, and the DIST (distance) for each leg (or segment) of the flight, the time and estimated fuel usage can be calculated.