Who is this article for?

Users managing segments data.

Access to the segments browser is required.

This article explains the nature of all segments in the application, including departure, arrival, and other segment types, as well as how to configure and name them correctly for the OPAS algorithm.

1. Understanding departure segments

Departure segments track aircraft movement from the stop bar through to take-off. The following segments are available:

• Dwell at Stop Bar: The aircraft waits at the stop bar to a runway before moving onto the runway
• Stop Bar to Runway Entrance: The aircraft moves from the stop bar onto the runway (generally a short segment)
• Runway Entrance to Line-up: The departure moves from the runway entrance threshold to where it stops at the line-up point, when thrust is engaged and take-off begins
• Dwell at Line-up: The departure stops at the line-up point before engaging thrust to take-off, generally awaiting final clearance from the tower
• Start of Roll to Wheels Up: The aircraft engages thrust and takes off

2. Understanding arrival segments

Arrival segments track aircraft movement from the runway threshold through to the taxi area. The following segments are available:

• Runway Threshold to Wheels Down: The arrival crosses the runway threshold to the estimated point it puts the wheels down
• Wheels Down to Runway Exit: The arrival taxis along the runway until it reaches a suitable or designated runway exit
• Runway Exit: The arrival crosses the runway exit onto the taxi area

3. Understanding other segment types

Additional segment types track aircraft movement on the stand, during pushback, taxi, and en-route phases:

• On Stand: The arrival is detected as passing from taxi phase into the stand area. The segment has a length of 60 seconds before closing
• Pushback: Detects when the aircraft is pushed back by a tug from the stand. A short stationary movement occurs while the tug detaches, which ends the pushback segment
• Taxi: For arrivals, this is the period between the end of Wheels Down to Runway Exit segment and start of On Stand segment. For departures, this is from the end of Pushback to the start of the next segment. The taxi segment may have stationary segments inside it, which do not contribute to the total time of taxi
• En-route Direct Route Extension (40-100 NM): The segment is identified as passing the 40 NM circular marker and proceeding to the 100 NM circular marker, or the reverse for arrivals
• En-route Filed Plan Extension (40-100 NM): Constructed from the flight plan, this represents the planned intention of the flight to proceed from the 100 NM marker to designated runway, or exiting from the zone for departures. This can be compared to the actual path and allows for efficiency comparisons

Note: Segment zones are primarily for on-ground segments. In-air segments are detected via alternate methods.

Examples of the segment zones in the Selection Zones tab of the Feature Manager are shown below:

4. Configuring segment naming syntax

To configure segments for recognition by the OPAS algorithm, follow the naming syntax below:

OS_[A|D]_[RwyName]_[Entry/Exit]_[Operation Segment Name]

Where:

• A|D: Arrival or Departure
• RwyName: Actual name of runway (for example, 27R)
• Entry/Exit: Entry or exit point (for example, A1, A2)

For entry/exit, the system takes this from either the last segment prior to entering the Wheels Up segment, or the first segment after exiting either of the Wheels Down segments. In some cases, due to missing radar, this may not be determined.

Important: For accurate functioning of the OPAS system, you must use the correct naming syntax with regard to upper and lowercase.

5. Reviewing a completed zone example

The following example shows a completed zone consisting of a simple block with four points in total:

The example demonstrates the following requirements:

• Naming conventions are followed
• The minimum and maximum heights are set to ensure any anomalous points not at ground level are still registered in the zone
• Transparency allows for some detail to be seen through the zone
• The zone is active and part of processing