Navigation

For simple aircraft with reciprocating engines, the Aircraft computer has an instruction book that probably includes Flight Manual/Pilot’s Operating Handbook (AFM/POH) sample problems so the pilot can become familiar with its supplied by the aircraft manufacturer provides gallons-per- functions and operation. [Figure 16-18] hour values to assist with preflight planning. Plotter When planning a flight, you must determine how much Another aid in flight planning is a plotter, which is a protractor fuel is needed to reach your destination by calculating the and ruler. The pilot can use this when determining TC and distance the aircraft can travel (with winds considered) at measuring distance. Most plotters have a ruler that measures a known rate of fuel consumption (gal/hr or lbs/hr) for the in both NM and SM and has a scale for a sectional chart on one expected groundspeed (GS) and ensure this amount, plus an side and a world aeronautical chart on the other. [Figure 16-18] adequate reserve, is available on board. GS determines the time the flight will take. The amount of fuel needed for a Pilotage given flight can be calculated by multiplying the estimated Pilotage is navigation by reference to landmarks or flight time by the rate of consumption. For example, a flight checkpoints. It is a method of navigation that can be used of 400 NM at 100 knots GS takes 4 hours to complete. If an on any course that has adequate checkpoints, but it is more aircraft consumes 5 gallons of fuel per hour, the total fuel commonly used in conjunction with dead reckoning and consumption is 20 gallons (4 hours times 5 gallons). In this VFR radio navigation. example, there is no wind; therefore, true airspeed (TAS) is also 100 knots, the same as GS. Since the rate of fuel The checkpoints selected should be prominent features consumption remains relatively constant at a given TAS, common to the area of the flight. Choose checkpoints that can you must use GS to calculate fuel consumption when wind be readily identified by other features, such as roads, rivers, is present. Specific range (NM/lb or NM/gal) is also useful railroad tracks, lakes, and power lines. If possible, select in calculating fuel consumption when wind is a factor. features that make useful boundaries or brackets on each side of the course, such as highways, rivers, railroads, and You should always plan to be on the surface before any of mountains. A pilot can keep from drifting too far off course the following occur: by referring to and not crossing the selected brackets. Never • Your flight time exceeds the amount of flight time place complete reliance on any single checkpoint. Choose you calculated for the consumption of your preflight ample checkpoints. If one is missed, look for the next one while fuel amount maintaining the heading. When determining position from checkpoints, remember that the scale of a sectional chart is 1 • Your fuel gauge indicates low fuel level inch = 8 SM or 6.86 NM. For example, if a checkpoint selected was approximately one-half inch from the course line on the The rate of fuel consumption depends on many factors: chart, it is 4 SM or 3.43 NM from the course on the ground. condition of the engine, propeller/rotor pitch, propeller/ In the more congested areas, some of the smaller features are rotor revolutions per minute (rpm), richness of the mixture, not included on the chart. If confused, hold the heading. If a and the percentage of horsepower used for flight at cruising turn is made away from the heading, it is easy to become lost. speed. The pilot should know the approximate consumption rate from cruise performance charts or from experience. Roads shown on the chart are primarily the well-traveled In addition to the amount of fuel required for the flight, roads or those most apparent when viewed from the air. there should be sufficient fuel for reserve. When estimating New roads and structures are constantly being built and consumption you must plan for cruise flight as well as startup may not be shown on the chart until the next chart is issued. and taxi, and higher fuel burn during climb. Remember that Some structures, such as antennas, may be difficult to see. ground speed during climb is less than during cruise flight Sometimes TV antennas are grouped together in an area near at the same airspeed. Additional fuel for adequate reserve a town. They are supported by almost invisible guy wires. should also be added as a safety measure. Never approach an area of antennas less than 500 feet above the tallest one. Most of the taller structures are marked with Flight Computers strobe lights to make them more visible to pilots. However, Up to this point, only mathematical formulas have been used some weather conditions or background lighting may make to determine such items as time, distance, speed, and fuel them difficult to see. Aeronautical charts display the best consumption. In reality, most pilots use a mechanical flight information available at the time of printing, but a pilot should computer called an E6B or electronic flight calculator. These be cautious for new structures or changes that have occurred devices can compute numerous problems associated with since the chart was printed. flight planning and navigation. The mechanical or electronic 16-12