Charts consist of a number of different procedures. By reading the charts textual description of a procedure and/or visually examining the chart, the procedure can be broken down into a number of steps or as the Nav Data Tool calls them, Directions.
Each Direction is defined by its type, e.g. FlyToNavAid or FlyTurnOntoRadial. Once a Direction has a type, the fields available to configure the Direction become enabled. Not all fields are applicable to a Direction. Fields that are in italics are optional.
Each Direction implements a specific algorithm to calculate a position on the map and to draw a suitable path on the map - thus creating the chart.
Direction Processing
Directions are processed in sequential order, starting at the first Direction until the end is reached. A chart can contain multiple procedures and each procedure must start with a Starting Direction.
Since procedures often overlap and share a common flight path, special Directions called Common Areas exist that allow a group of Directions to be grouped as a Common Area.
Once a Common Area has been defined, subsequent procedures can reference one or more Common Area's instead of duplicating the Directions.
Common Areas can be nested within each other.
Do not confuse Common Areas with SID, STAR transitions and Initial Approaches as these are shared between procedures by matching approach types and runways.
Starting Directions
There are a number of Starting Directions that are the very first Direction that must be used at the start of a procedure. These are:
SIDStart - when defining a SID procedure;
STARStart - when defining a STAR procedure;
InitialApproachStart when defining an Initial Approach or Approach Transition procedure;
ApproachStart when defining an Approach procedure;
SIDTransitionStart when defining a SID transition procedure. These procedure types follow on from a SIDStart.
STARTransitionStart when defining a STAR transition procedure. These procedure types precede a STARStart.
Common Area Directions
DefineCommonStart indicate the start of a grouping of Directions. Specify a Name so it can be referenced later.
DefineCommonEnd indicates the end of a grouping of Directions.
UseCommon indicates that from this point the procedure should use the Directions defined within the Common Area selected
Headings and Radials
Headings are always magnetic and should be the heading of the direction of travel.
Radial headings are always magnetic and should be the heading from the nav aid if the nav aid is a VOR, VORDME or TACAN. Radial headings with other types of nav aid should be treated as Headings defined above.
Direction Fields
Nav Aid This is the ICAO identifier of a navigational aid to be used. Some Directions need two nav aids (e.g. FlyToRadialsFix) which can be chosen by clicking the 1 or 2 radio buttons. If the entered nav aid is valid, the Magnetic Variation area buttons will be enabled so that magnetic variation for the nav aid with this Direction can be adjusted.
Hdg This is the magnetic heading or radial to be used.
Dist/Leg is for FlyHoldingPattern Directions only. If Is Leg is ticked, the field represents the leg time in minutes, otherwise it represents a distance in nautical miles.
Radius is for Directions that create turns such as FlyTurnToHeading. Leaving this value at 0 means the radius of the turn will be automatically created. Most of the time you will not need to set a radius, however there may be times you need to specify the turn radius in nautical miles to get the correct position to match the chart.
Spd, Alt, and restriction types are for specifying speed and altitude restriction data for the Direction.
Left, Right are for Directions that involve a turn and indicate the turn direction.
Type when not used with ApproachStart & InitialApproachStart Directions represents a nav aid type. When settings the type, the Nav Data Tool sees the calculated end point of the Direction as a Custom Nav Aid. Use this when defining points on an Approach instead of having to manually create the nav aids in Add Custom Nav Aid.
Type when used with ApproachStart & InitialApproachStart Directions represents what navigational landing aids/system types are applicable to the Approach. Multiple types can be selected.
Recip/Altn stands for Reciporal or Alternative. Depending upon the Direction Type having this ticked will either:
- use the reverse (reciprocal) of the value in Hdg. E.g. when using FlyToRadialDMEFix.
- toggle between two alternative points on a line or circular flight path. E.g. FlyCurrentHeadingDistanceDMEFix.
The filled value means let the Nav Data Tool choose.
Overfly means overfly the point the Direction uses as an end point in the map. Although the chart will not change, it will affect the Nav Data produced, so its best to tick this field only when testing the Nav Data.
Suffix is used with ApproachStart & InitialApproachStart Directions. Some charts have a Suffix code that can be recorded here so it distinguishes different approaches. The Suffix will appear in the Nav Data.
Name is used with all the Starting Directions types except the ones for Approaches. This field is used to choose, define, rename or delete procedure names using the Add, Rename, Delete Procedure buttons shown underneath it.
Direction Types
SIDStart - when defining a SID procedure. This requires the entry of a procedure Name (either add one or use an existing name) and a Runway (in the Airport & Chart Name Area).
STARStart - when defining a STAR procedure. This requires the entry of a procedure Name (either add one or use an existing name) and one or more Runways (in the Airport & Chart Name Area).
InitialApproachStart when defining an Initial Approach or Approach Transition procedure. This requires the selection of applicable nav aid/system Types and one or more Runways (in the Airport & Chart Name Area).
ApproachStart when defining an Approach procedure. This requires the selection of applicable nav aid/system Types and a Runway (in the Airport & Chart Name Area).
SIDTransitionStart when defining a SID transition procedure. These procedure types follow on from a SIDStart. This requires the entry of a procedure Name (either add one or use an existing name) and one or more Runways (in the Airport & Chart Name Area).
STARTransitionStart when defining a STAR transition procedure. These procedure types precede a STARStart. This requires the entry of a procedure Name (either add one or use an existing name).
StartFacingHeading is a useful direction following a STARStart. It forces a particular heading to start drawing the chart instead of using 0 degrees. E.g. the chart may be expecting to start at a nav aid defined in STARStart but the next step assumes a turn starting from 180 degrees to 270.
FlyHoldingPattern defines an aircraft holding point and pattern. The point is wherever the previous direction ended on the map. The Hdg should be the download leg heading.
FlyHeadingDistance defines a point on the map based on a Hdg and Dist.
FlyHeadingDistanceDMEFix defines a point on the map based on the intersection of Hdg and the Dist from the Nav Aid.
FlyHeadingUntilAltitude defines a point on the map based on flying on Hdg until the Alt is reached. The distance is calculated based on Spd restrictions or Max Speed KIAS and Vert Speed FPM from Settings.
FlyTurnToHeading defines a point on the map by turning Left or Right to Hdg.
FlyTurnOntoRadial defines a point on the map by turning Left or Right to intercept a radial (Hdg) of the Nav Aid.
FlyTurnToRadialFix defines a point on the map by turning Left or Right ending where the radial (Hdg) of the Nav Aid crosses the turn. Use Recip/Altn if the point is incorrect.
FlyTurnToRadialsFix defines a point on the map by turning Left or Right to where two Nav Aids and their respective Hdg's intersect.
FlyTurnToDistanceDMEFix defines a point on the map by turning Left or Right until the Dist from Nav Aid is reached. Use Recip/Altn if the point is incorrect.
FlyTurnTowardsNavAid defines a point on the map by turning Left or Right towards the Nav Aid.
FlyTurnTowardsNavAidOnRadial ends at the Nav Aid by turning Left or Right onto a radial (Hdg) towards the Nav Aid.
FlyTurnToNavAid ends at the Nav Aid by turning Left or Right.
FlyToNavAid ends at the Nav Aid.
FlyToInterceptRadial defines a point on the map ending at the Dist from the Nav Aids radial (Hdg).
FlyCurrentHeadingTurnOntoRadial continues travel on the current heading until a point is reached where the Nav Aids radial (Hdg) can be turned onto, either Left or Right.
FlyCurrentHeadingTurnOntoRadialBeforeNavAid continues travel on the current heading until a point is reached where the Nav Aids radial (Hdg) can be turned onto, either Left or Right. The end of the turn will be before or at the 2nd Nav Aid entered that sits on the radial.
FlyCurrentHeadingTurnOntoRadialDMEFix continues travel on the current heading until a point is reached where the Nav Aids radial (Hdg) can be turned onto, either Left or Right. Travel will continue along the radial until the Dist from the Nav Aid is reached.
FlyCurrentHeadingDistanceDMEFix continues travel on the current heading until the Dist from the Nav Aid is reached. Use Recip/Altn if the point is incorrect.
FlyCurrentHeadingInterceptRadial continues travel on the current heading until the Nav Aids radial (Hdg) crosses the path of travel.
FlyCurrentHeadingUntilAltitude continues travel on the current heading until the Alt is reached. The distance is calculated based on Spd restrictions or Max Speed KIAS and Vert Speed FPM from Settings.
FlyToRadialDMEFix defines a point on the map where the Dist on the Nav Aids radial (Hdg) meet.
FlyToRadialsFix defines a point on the map where the Nav Aids radials (Hdgs) intersect.
FlyCircle defines a series of points that form a circle either Left or Right centered on the Nav Aid. The interval of the points is defined in Settings (Circle Degrees Int).
Vectors indicates that ATC instructions will be followed from now on. Does not show anything on the chart.
Land is using on Approaches and defines a point at the runway threshold. The runway is chosen in ApproachStart.