Who is this article for?

Noise analysts who need to detect and measure aircraft holding.

Access to the ANOMS Noise Analyst Workbench is required.

Many airports use holding zones, or stacks, to queue arrivals when a runway cannot be assigned immediately — aircraft complete one or more circuits in a designated area until air traffic control clears them to land.

Understanding how detection works

ANOMS uses gates to detect holding zones. Once a holding zone is set up, ANOMS can determine whether a flight used it, how many circuits the flight made, and how long (in seconds) the flight spent in the holding pattern.

A holding zone is built from a single gate placed across the entry and exit of the holding pattern. Flights penetrate the gate, loop around, and re-enter the arrival path at the same point, so the gate acts like a counter for each circuit.

Note: If a flight does not penetrate the holding zone gate, ANOMS will be unable to assign a holding zone to it.

Creating a holding zone

It is recommended that you first load some arrival tracks that are known to have been in holding zones, and map them for reference when building the gate.

To create a holding zone:

1. Use the Operations Browser to find arrival operations that are known to have used a holding zone (or pattern).
2. Map the operations to the Map Browser.
3. Use the Gate/Corridor Editor to create a gate that sits across the entry and exit of the holding zone — see the article Creating a track-keeping gate.
4. From the main menu, select Input.
5. Select Holding Zone Manager.
6. Click the New button.
7. Enter a Name for the holding zone.
8. Use the drop-down list to select a Detection gate for the holding zone.
9. Use the check box to select whether the holding zone will be active.
10. Enter an optional description of the holding zone.
11. Click OK to confirm and save the settings.

Tip: Give the gate a descriptive name, similar to the holding zone, so you can identify it later.

Note: If a holding zone is not active, ANOMS will not attempt to detect flights entering it. An active zone is part of overnight processing, and flight records are marked if they qualify.

Editing a holding zone

To edit a holding zone:

1. From the main menu, select Input.
2. Select Holding Zone Manager.
3. Select an existing holding zone.
4. Click the Edit button.
5. Edit the properties as required.
6. Click OK to confirm the changes, or Cancel to discard them.

Deleting a holding zone

To delete a holding zone:

1. From the main menu, select Input.
2. Select Holding Zone Manager.
3. Select an existing holding zone.
4. Click the Delete button.

Querying holding zone activity

Use the Query Generator to search for operations that used a certain holding zone, spent a particular amount of time holding, or made a specific number of circuits.

The available criteria are: