Terrain Following

A Terrain Following procedure is a point to point procedure that applies terrain data to the aircraft's route, adjusting its altitude or flight path as needed to avoid intersecting with geographic features. It is not constrained by the aircraft's ceiling. The process of terrain following begins at the end of the previous procedure and ends at the Terrain Following procedure's site. The Terrain Following procedure disregards the Climb and Descent models, using the Terrain Follow performance model's Max Pitch Angle and Speed values to define climbs and descents.

For the purposes of 3D editing, the altitude of control points is defined by the local terrain height plus the minimum terrain clearance altitude (AGL Altitude) specified for the procedure. The aircraft may fly higher if the parameters of the Terrain Follow performance model, the local terrain, and the specified ground path over the terrain require the aircraft to fly higher.

The procedure contains one control point - the procedure site - as indicated in the diagram below.

AGL Altitude

Define the minimum Above Ground Level (AGL) altitude that the aircraft will maintain during the procedure. Click Paste Profile Item to define this value with an altitude value copied from the Mission Profile.

Navigation Options

Navigation Options parameters define the heading or course of the aircraft at the beginning of the procedure and the direction of turns taken to arrive at the procedure site.

Table - Navigation Options Parameters

Parameter	Description
Nav Mode	Define the heading or course of the aircraft at the beginning of the procedure. Select from the following options: Fly Direct - The aircraft will fly directly to the procedure site from the end of the previous procedure, turning as necessary. Arrive on Course for Next Procedure - The aircraft will start or arrive at the procedure site on a course determined by the next procedure so as to avoid an immediate turn correction by the next procedure. Arrive on Course - The aircraft will start or arrive at the procedure site on a specific course. Define the course and then specify a True or Magnetic north reference using the drop-down menu. Inscribed Turn - The aircraft will perform an inscribed turn, placing it on a course to the first control point of the next procedure at a point no further than half of the distance to that waypoint. The aircraft will attempt to adhere to the Turn Factor, but will reduce that value if needed to ensure that it does not arrive on the final course beyond the halfway mark. Similarly, the aircraft may violate the acceleration performance model to ensure that it completes the turn in the proper distance; in the event that the model is violated, information will be displayed in the Message Viewer. When performing an inscribed turn, the aircraft will not pass over the current procedure's site unless the turn radius is zero. Arrive on Heading into Wind - The aircraft will start or arrive at the procedure site on a heading into the wind.
First Turn	Define the direction of the turn made from the end of the previous procedure as the aircraft sets its course toward the procedure site. If the selected Nav Mode does not include a turn, then this parameter will be ignored. Select from the following options: Automatic - Aviator will determine the direction of the turn. Turn Left - Specifies a left turn. Turn Right - Specifies a right turn.
Second Turn	Define the direction of the turn made to achieve the outbound course at the procedure site. If the selected Nav Mode does not include a turn, then this parameter will be ignored. Select from the following options: Automatic - Aviator will determine the direction of the turn. Turn Left - Specifies a left turn. Turn Right - Specifies a right turn.

Parameter

Description

Nav Mode

Define the heading or course of the aircraft at the beginning of the procedure. Select from the following options:

Fly Direct - The aircraft will fly directly to the procedure site from the end of the previous procedure, turning as necessary.
Arrive on Course for Next Procedure - The aircraft will start or arrive at the procedure site on a course determined by the next procedure so as to avoid an immediate turn correction by the next procedure.
Arrive on Course - The aircraft will start or arrive at the procedure site on a specific course. Define the course and then specify a True or Magnetic north reference using the drop-down menu.
Inscribed Turn - The aircraft will perform an inscribed turn, placing it on a course to the first control point of the next procedure at a point no further than half of the distance to that waypoint. The aircraft will attempt to adhere to the Turn Factor, but will reduce that value if needed to ensure that it does not arrive on the final course beyond the halfway mark. Similarly, the aircraft may violate the acceleration performance model to ensure that it completes the turn in the proper distance; in the event that the model is violated, information will be displayed in the Message Viewer. When performing an inscribed turn, the aircraft will not pass over the current procedure's site unless the turn radius is zero.
Arrive on Heading into Wind - The aircraft will start or arrive at the procedure site on a heading into the wind.

First Turn

Define the direction of the turn made from the end of the previous procedure as the aircraft sets its course toward the procedure site. If the selected Nav Mode does not include a turn, then this parameter will be ignored. Select from the following options:

Automatic - Aviator will determine the direction of the turn.
Turn Left - Specifies a left turn.
Turn Right - Specifies a right turn.

Second Turn

Define the direction of the turn made to achieve the outbound course at the procedure site. If the selected Nav Mode does not include a turn, then this parameter will be ignored. Select from the following options:

Automatic - Aviator will determine the direction of the turn.
Turn Left - Specifies a left turn.
Turn Right - Specifies a right turn.

Enroute Options

Field	Description
Reduce Turn Radii	Select to force the aircraft to use the minimum speed for computing the normal turn radius. The maximum speed radius will only be generated if the turn sequence at that radius is the same as the minimum radius. If the aircraft is flying at a very high speed, it may exceed its Turn G limit in this mode.
Turn Factor	The Turn Factor is the maximum amount - expressed as a multiplier - that the turn radius will be increased to minimize the bank angle required to complete the turn. The full circles that correspond (or are tangent) to the start/stop turns at the extended radius may not intersect if the Turn Factor is set high enough. This parameter is a limit and may not actually be achieved due to the requirement to generate an appropriate turn sequence. You can adjust the slider or enter the value manually in the box, with the minimum value being 1 and the maximum value being 10.

Field

Description

Reduce Turn Radii

Select to force the aircraft to use the minimum speed for computing the normal turn radius. The maximum speed radius will only be generated if the turn sequence at that radius is the same as the minimum radius. If the aircraft is flying at a very high speed, it may exceed its Turn G limit in this mode.

Turn Factor

The Turn Factor is the maximum amount - expressed as a multiplier - that the turn radius will be increased to minimize the bank angle required to complete the turn. The full circles that correspond (or are tangent) to the start/stop turns at the extended radius may not intersect if the Turn Factor is set high enough. This parameter is a limit and may not actually be achieved due to the requirement to generate an appropriate turn sequence. You can adjust the slider or enter the value manually in the box, with the minimum value being 1 and the maximum value being 10.