Nav Charts

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Nav Charts
2013-09-17 19:26:36

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  1. Othormorphism requires what two qualities?
    the scale, although varying throughout the map, is the same in all directions at any point, so that very small areas are represented by correct shape and bearings are correct.

    Parallels of Lat must cross Meridians at 90
  2. Formula for Chart Scale
  3. Describe Mercator Projection
    • Cylindrical Projection
    • Rhumb lines are straight
    • Great Circle tracks are concave to the equator
    • All Meridians appear as straight lines
    • Parallels of Lat appear as straight lines but spread out towards the poles
    • Impossible to project the poles
    • Parallels cross Meridians at 90

  4. On a Mercator chart how does the scale expand towards the poles?
    Expands as the Secant (1/Cos) of the Latitude

    • Or easier just multiply the denominator of the scale fraction by the cos of the Latitude.

    Or if moving towards the equator, multiply the denominator by the sec of the lat change
  5. Uses of a Mercator Chart
    Plotting Charts for Lats 70N - 70S where the requirement is to fly Rhumb Line tracks rather then Great Circles.

    Topographical maps of Equatorial regions  because at low lats the chart is almost constant scale
  6. Lambert Chart Properties
    • Parallels are curved towards the poles and are spaced almost constantly
    • Meridians are straight lines that converge towards the poles
    • Rhumb Lines are concave to the nearest pole
    • Great Circles are straight
  7. Uses of Lambert Charts
    • When Great circles are to be plotted and flown.
    • Topographical Charts
    • Met Synoptic Charts
    • Radio and Nav Aid Charts
  8. What is the temp change in the ISA and JetSA

    When is the tropopause?
    ISA 1.98 / 1000ft then constant -56.5

    JSA 2.00 / 1000ft and no tropopause
  9. Define Visibility
    1) Transparency of the atmosphere

    2) The distance over which significant dark objects can be seen and recognized on a light background such at the horizon
  10. Define Prevailing and Flight visibility
    From the ground (METAR) (more than 50% of horizon circle)

    Forward from the flight deck
  11. Def Runway Visual Range

    How is it assessed?
    The max distance at which pilot may expect to see runway lights or markers during takeoff or landing roll From a point 5m above the touchdown point 

    In less than 1500m viz, observer sits 76m from centreline at touchdown point and counts lights he can see
  12. Define Slant Viz Range
    The furthest distance that ground markings or lights can be seen at any time during the approach. the distance between the pilots eye and the furthest light that can be seen

    Note: RVR is from the 5m point
  13. State Altimeter setting in Oceanic Airspace
    1013.2 except when in these QNH zones

    • Rarotonga
    • Samoa
    • Norfolk Island

    Also T/O and landing use appropriate field QNH
  14. State Oceanic Flight Levels
    Odd People fly east Magnetic

    0000-179o 3000ft-FL390 then at 4000ft intervals

    1800-3590 4000ft-FL400 then 4000ft intervals
  15. State NZ FIR flight levels.
    odds south 

    evens north

    Note when going from Oceanic to NZFIR on an international flight plan, the oceanic level should be planned for. ATC may change this.
  16. State Time law UTC to observer
    Observer East (of Greenwich) UTC least

    Observer West (of Greenwich) UTC best

    Always work through UTC to solve problems
  17. How many segments does GNSS have and what are they called?

    How many Sats are there?
    3 segments

    Space (24 sats)


  18. How many Sats needed for RAIM
    5 needed to detect a fault. Sat constellation is designed so at least 5 are in view at any point on earth at all times
  19. What is ephemeris error?

    What is clock error?

    Max error size?
    1) Error in predicted position and orbit path due to pull from the sun and moon and by pressure of solar radiation. Max 2.5m

    2) Error in onboard Clock time. Max 1.5m

    Both are  sorted when they pass over monitoring station twice daily
  20. What are propagation delays in GPS

    Max Error?
    Ionospheric and Atmospheric Max 5.0m

    Because light only travels predictably in a vacuum. pseudo random code is broadcast on 2 diff freq which will show slowing if it exists as the fault is different at different freqs
  21. What is multipath error in GPS
    Signal bounce style error
  22. What is GDOP in GPS
    Geometric Dilution of precision.

    Wider the angle between the sats the smaller the error
  23. Whats is the max receiver error in GPS?
  24. What is DGPS?
    differential GPS uses ground based reference stations to check integrity of satellite information, and broadcast any errors

    Uses the GBAS (Ground Based Augmentation system)
  25. What is ADS-B
    Automatic Dependent Surveillance - Broadcast

    Means of ATC surveillance using ground based network.

    A/C broadcasts it's position using GPS technology. MODE S transponders broadcast 2 times a second position and other parameters.

    Sends it to ground based stations and other A/C

    Ground based stations can uplink weather info etc
  26. What is a ADS-B transmission of data from an A/C called.

    What frequency
    Extended Squitter (ES)

    1090MHz  (ten ninety)
  27. What is ASD-B "in" capability
    Can receive info from other A/C and use on a Cockpit Display or Traffic Information (CDTI)

    Looks like TCAS but also get ID numbers and track trend data
  28. In a Lambert chart, how much of the chart lies between the two standard parallels to make it accurate?
    2/3 BY AREA

    1/6 above the top one

    1/6 below the bottom one