Hot air balloon pilots take pride in their ability to navigate with precision. To execute a flight which follows a predetermined plan directly to a target is a source of real satisfaction. Navigational skill is a required skill needed to participate in competition flying. Every preflight action should include a proposed track that is transferred to a chart. The prime requirement for success in navigation is knowledge of a few simple facts and the ability to exercise good judgment based upon those facts. Balloon pilots are required to know only the rudiments of basic navigation. As more flight experience is gained, especially through long distance flights, more knowledge of navigation will be desirable.
To navigate successfully, a pilot should be able to determine a balloons launch location on his chart. In flight, the pilot verifies his position along his route by pilotage and by dead reckoning. Pilotage is the use of visible landmarks to verify the aircrafts position. Dead reckoning is the laying out of a proposed tract on a chart in a known direction and speed.
The basic form of navigation for a balloon pilot is through pilotage. This type of navigation should be mastered first. An understanding of the principles of dead reckoning, however, will enable the pilot to make necessary calculations of flight time and wind shifts.
Aeronautical charts: The National Ocean Survey (NOS) publishes and sells aeronautical charts of the United States and foreign areas. The type of charts most commonly used by balloon pilots are:
These charts are designed for visual navigation and for slow speed aircraft such as a balloon. The topographical information featured on these charts consists of the portrayal of relief and a judicious selection of visual checkpoints used for VFR flight. The aeronautical information on sectional charts includes visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions and related data. A “Class B Airspace Chart” is a blowup of the area around a major airport designated as Class B Airspace. Balloon pilots prefer the Class B Airspace Chart because it is in an easier-to-read scale. If the area to be flown in does not have Class B Airspace, then a Sectional Chart will have to be relied on for navigational and informational purposes. The topographical information on these charts includes cities, towns, principal roads, railroads, distinctive landmarks, drainage and relief. Relief is shown by spot elevations, contours, in radiant color tints.
It is important that the pilot checks the publication date on the aeronautical chart to be used. Obsolete charts should be discarded and replaced by new editions. This is important because revisions include changes in radio frequencies, new obstructions, and changes in designation of airspace. I have a subscription from Sporty's whcih sends me a udated chart ever quarter.
Because of the relatively short distances that balloons fly, it is appropriate that road maps also be used for navigation. Most highway departments or counties publish county road maps. These are excellent for use in balloon navigation. The difference between a chart and a map is that the chart has a grid in latitude and in longitude.
Sectional Aeronautical Charts: A chart name and title appear on each chart. The chart legend lists various aeronautical symbols as well as information concerning terrain and contour elevations. Referring to the legend, aeronautical, topographical and observation may identify symbols. Many landmarks, which can be easily recognized from a balloon, are identified on the chart by brief descriptions and symbols marking their exact location.
Relief: The elevation of land surface, relief, is shown on the aeronautical charts by brown contour fines drawn at 250-foot intervals. These areas are emphasized by various tints, as indicated in the color legend appearing on each chart. The closer the contour lines are together on the chart, the more steep the terrain.
Aeronautical Data: The aeronautical information on the Sectional Chart is explained on the legend section of the chart. Each omni directional radio range (VOR) has a magnetic compass rose around it. Airports and information pertaining to airports having a Control Tower are shown in blue. All other airports and information pertaining to those are shown in magenta adjacent to the airport symbol, which is also in magenta.
The symbol for obstructions is another important feature. The elevation of the top of an obstruction above sea level is given in blue figures (without parenthesis) adjacent to the obstruction symbol. Immediately below this section of figures is another set of light blue figures enclosed in parenthesis, which represents the height of the top of the obstruction above ground level. Obstructions which extend less than 1,000 feet above the terrain are shown by one type of symbol and those obstructions that extend 1,000 feet or higher above ground level are indicated by a different symbol. Specific elevations of certain high points and terrain are shown on charts by dots accompanied by small black figures indicating the number of feet above sea level.
The chart also contains larger bold-faced blue numbers, which denote maximum elevation figures. These figures are shown in quadrangles bounded by tic lines of latitude and longitude and are represented in 1,000s and 100s of feet above mean sea level. These maximum elevation figures are based on information available concerning the highest known feature in each quadrangle, including terrain and obstructions.
Meridians and parallels: The equator is an imaginary circle equidistant from the poles of the earth. Circles parallel to the equator (lines running east and west) are parallels of latitude. They are used to measure degrees of latitude north or south of the equator. The angular distance from the equator to the pole is 90 degrees.
Meridians of longitude are drawn from the North Pole to the South Pole and are at right angles to the equator. The "Prime Meridian" which passes through Greenwich, England, is used as the zero line from which measurements are made in degrees east and west to 180 degrees.
Any specific geographical point can be located by reference to its latitude and longitude. Each degree of latitude or longitude is divided into minutes and seconds. One minute of one degree of latitude is equal to one nautical mile.
The meridians are also useful for designating time belts. A day is defined as the time required for the earth to make on complete revolution of 360 degrees. Since the day is divided into 24 hours, the earth revolves at the rate of 15 degrees an hour. Noon is the time when the sun is directly above a meridian; to the west of that meridian is forenoon, to the east is afternoon.
The standard practice is to establish a time belt for each 15 degrees of longitude. This makes a difference of exactly one hour between each belt. In the United States there are four time belts - Eastern (75 degrees), Central (90 degrees), Mountain (105 degrees), and Pacific (120 degrees). The dividing lines are somewhat irregular because communities near the boundaries often find it more convenient to use time designations of neighboring communities or trade centers.
When the sun is directly above the 90th meridian, it is noon Central Standard Time. At the same time it will be 1:00 p.m. Eastern Standard Time (EST), 11:00 a.m. Mountain Standard Time (MST), and 10:00 a.m. Pacific Standard Time (PST). When "daylight saving" time is in effect, generally between April and October, the sun is directly above the 75th meridian at noon, Central Daylight Time (CDT). CST is 0600 and CDT is 0700 when it is 1200 Greenwich time.
In most aviation operations, time is expressed in terms of the 24-hour clock. Air traffic control instructions, weather reports and broadcasts are all given in Greenwich time.
Measurement of Direction: By using the meridians, directions from one point to another can be measured in degrees, in a clockwise direction from true north. To indicate a course to be followed in flight, draw a line on the chart from the point of departure to the destination and measure the angle, which this line forms with a meridian. Direction is expressed in degrees.
Variation: To use the compass accurately, correction must be made for magnetic variation. Variation is the angle between true north and magnetic north. It is expressed as east variation or west variation depending upon whether magnetic north is to the east or west of true north, respectively.
The north magnetic pole is about 1,300 miles from the geographic or true North Pole.
The earth is not uniformly magnetized. In the United States the needle usually points in the general direction of the magnetic pole but it may vary in certain geographical localities by many degrees. Consequently, the National Ocean Survey has carefully determined the exact amount of variation at thousands of selected locations in the United States. The amount and direction of variation, which change slightly from time to time, are shown on aeronautical charts as broken red fines, called isogonic lines, which connect points of equal magnetic variation. (The line connecting points at which there is no variation between true north and magnetic north is the agonic line).
On the west coast of the United States, the compass needle points to the east of true north; on the east coast the compass needle points to the west of true north. Zero degrees variation exists on the agonic line, which runs roughly through Lake Michigan, the Appalachian Mountains, and off the cost of Florida, where magnetic north and true north coincide.
Because courses are measured in reference to geographical meridians, which point toward true north, and these courses are maintained by reference to the compass which points along a magnetic meridian in the general direction of magnetic north, the true direction must be converted into magnetic direction for the purpose of flight. Adding or subtracting the variation, which is indicated by the nearest isogonic line on the chart, makes this conversion. The true heading, when corrected for variation, is known as magnetic heading. To convert TRUE course or heading to MAGNETIC course, note the variation shown by the nearest isogonic line, if variation is west, add; if east, subtract.
Some method should be devised for remembering whether to add or subtract variation. The following may be helpful: When going from true to magnetic, East is least (subtract) and West is best (add). The formula for this is written: True heading + West variation - East variation = magnetic heading. TH±V=MH.
Compass Rose: If the variation is known, a stick-on compass rose can be placed on the map launch point. Draw a true north fine through the point. Next draw a magnetic north line (east to the right or west to the left) the number of degrees of variation from true north. Affix the compass rose to the map aligned with the magnetic north line.
Sectional Plotter: A sectional plotter is a combination of protractor and straight edge with distance marked off to the scale of the sectional chart. It is used by laying it over a meridian of longitude at the hole in the center of the protractor. The straight edge is then rotated about the longitude line to match the desired direction. A line is drawn representing the course to be flown. The plotter may be used to mark off the distance to be traveled on the course line.
Deviation: Deviation is the deflection caused in a magnetic compass by the magnetic influence within an aircraft. These are negligible in a balloon and generally no correction is made for deviation.
Preparation of a Flight Profile: Setting out a predetermined flight track is a part of preflight preparation and is strongly recommended for all types of aircraft. Most balloon pilots, other than competition pilots, tend to minimize this flight planning process. The emphasis for balloon pilots instead has been placed on their piloting ability to successfully cope with the in-flight variables as they are encountered.
A good habit to form for any student is to always prepare a written flight plan. In its simplest form, it can consist of locating the launch point on the map. Draw a line on the map representing the magnetic direction of the proposed flight. Mark off the time in 15-minute intervals according to the estimated wind speed to be encountered. This is known as a dead reckoning line.
A more sophisticated flight plan will train the student to do the following:
BASIC NAVIGATION CALCULATIONS
Basic navigation for the balloon pilot consists of time, speed and distance calculations. These problems are simple enough to figure in ones head, with paper and pencil or using a common electronic calculator. The following navigational problems can be used to test the knowledge of a student in this basic area.
Determining en-route time for a flight: In pre-flight planning, the pilot computes the estimated ground speed based on actual observation or forecast winds aloft. Observed wind speeds are estimated from flags, chimney smoke and such other visual indicators. Pibals are highly recommended for use in pre-flight planning. The pilot records the wind speed and direction at the surface, and at higher altitudes until the pibal goes out of sight. The winds aloft forecast should be relied on for the upper winds. With this information at hand, the pilot will be able to calculate the time of a flight at a given altitude.
Practice problems:
If ground speed of (a) ___________ is maintained, how much time will be required to fly a distance of (b) __________?
Determining ground speed during flight: During flight a pilot may wish to determine the actual ground speed. At liftoff, the pilot checks the time and again when passing over a known checkpoint. Distance is measured between the checkpoints on the chart and the length of time taken to fly the distance is noted. With these two figures, ground speed can be determined.
Practice problems:
A balloon flies (a) ___________ miles in (b) __________minutes. What is the ground speed?
Converting knots to miles per hour: Since the winds aloft forecast gives the wind in knots, a pilot should be able to convert knots to statute miles per hour, if desired, to determine the correct ground speed. Since knots actually mean nautical miles per hour, the problem is converting nautical miles to statute miles. There are approximately 1.15 statute miles to each nautical mile and .87 nautical miles in one statute mile.
Calculating time to climb: When approaching an obstacle, a pilot must calculate at what point a climb must be started in order to clear the obstacle. The wind speed, proposed ascent rate, current altitude and height of the obstacle must be known. For example, a balloon was flying at 6 knots, at an altitude of 900 feet MSL, and approaching a 2000-foot MSL tower, and the pilot wanted to clear the tower by 1000 feet. At what distance from the tower must the pilot start the ascent at 300 feet per minute?
Solution:
| Height of Tower | 2000 |
| Clearance | 1000 |
| Current Altitude | 3000 |
| Height too Climb | 2100 |
At 300 feet per minute climb, it will take seven minutes to climb 2100 feet. Sixty minutes divided into 6 knots equals .1 nautical miles per minute. In seven minutes, the balloon will travel .7 nautical miles per hour. The pilot will have to start the ascent .7 miles downwind of the tower.