L1 Instructor Self Test Part 4 Nav.txt

  1. What is the scale of the World Aeronautical Chart (WAC) commonly used for gliding?
    1: 1,000,000
  2. On which aeronautical charts are areas of controlled airspace shown?
    En-Route Charts, Low (ERC LOW) and Visual Terminal Charts (VTC)
  3. Where is it possible to purchase the required charts for safe cross-country navigation?
    The Airservices Australia (AA) Publications Centre, P.O. Box 1986, Carlton South, 3053. Phone 1800 33 1676 or 9342 2000 for Melbourne residents. (Airways and Radio Procedures for Glider Pilots)
  4. What is "variation"?
    Variation is the difference between true north and magnetic north. A compass will usually have some kind of error wherever it is and the error may be in an easterly or westerly direction. In Australia, magnetic variation varies from 3 degrees west in WA to 13 degrees east in some areas of the eastern seaboard. (BGK)
  5. What is the commonly-used jingle for remembering the effect of variation?
    Variation west, magnetic best, variation east, magnetic least. If variation is west, add the variation to the required track to get the magnetic heading. If variation nis east, subtract the variation from the required track to get the magnetic heading.
  6. What is "deviation"?
    Deviation is compass error caused by metallic objects (structure or instruments) in the glider. It is minimised for each glider by "swinging" the compass on the ground, a process by which small magnets in the compass are adjusted as the glider is "swung" to each of the cardinal headings in turn. Compass swings must be carried out with all electrical equipment, such as variometers and radios, in the position they would normally be in flight, as their influence may change considerably between their on and off positions
  7. Define the terms "heading", "track" and "drift".
    Heading is the direction in which the aircraft is pointing (the direction shown by the compass). Track is the path of the aircraft over the ground (different from heading if a crosswind component). Drift is the angle between heading and track
  8. What is the difference between airspeed and groundspeed?
    Airspeed is the speed through the air, indicated by ASI. Groundspeed is the speed over the ground, which is the glider's airspeed plus or minus the windspeed where the glider is flying
  9. What is the "triangle of velocities"?
    The triangle formed by drawing a diagram of the heading, track and wind velocity
  10. What is an "isogonal" and where would you find one?
    Isogonal: a line joining places of equal magnetic variation. Shown on WAC charts as broken purple lines at half-degree intervals, with the variation shown along the lines. Shown on ERC LOW charts as broken green lines at one-degree intervals. Note that magnetic variation is also shown on VTCs, numerically at the bottom of each chart and in pictorial form on the aerodrome diagrams on each title page.
  11. What is "GPS"?
    Global Positioning System. Gives an accurate lat/long position, and can give height. IGC (International Gliding Commission) has stated that GPS shall henceforth be known as GNSS (Global Navigation Satellite System)
  12. What action would you take if you realised you were lost?
    Don't panic. Go back to compass and maintain desired heading until you identify something. If unsuccessful, request assistance by radio. If still unsuccessful, land (especially if low or late in the day), ask someone where you are and telephone.
Card Set
L1 Instructor Self Test Part 4 Nav.txt
L1 Instructor Navigation