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Validation status

When a validation is active, the callsign cell blinks grey. Click it to open the Validation Status window.

Active validation on a strip

Validation status window

  1. Click the blinking callsign to open Validation Status.

  2. Read the message and use the action button if one is shown.

  3. If no action button is offered, correct the issue on frequency, then click ACKNOWLEDGE.

Validation Trigger Action
Duplicate squawk Two strips share the same squawk ASSIGN NEW
Wrong squawk Pilot transmitting a different squawk than assigned Correct on frequency → acknowledge
PDC invalid Invalid runway or SID in the PDC request OPEN DCL MENU
Custom PDC PDC request contains free-text or manual remarks OPEN DCL MENU
Runway type Assigned runway not suitable for the aircraft OPEN DCL MENU
Taxiway type Holding point incompatible with aircraft type/category ASSIGN HS
CTOT CTOT is more than 10 minutes away ASSIGN HP
Landing clearance Leading arrival not marked cleared to land CLEAR TO LAND

Duplicate squawk dialog

Two strips have been assigned the same squawk code. Click ASSIGN NEW to issue a new one.

Wrong squawk dialog

The pilot is transmitting a squawk that differs from the one assigned. Correct it on frequency, then acknowledge.

PDC invalid dialog

The PDC request contains an invalid runway or SID combination. Click OPEN DCL MENU to correct and re-send.

Custom PDC dialog

The PDC request contains free-text or manual-handling remarks that require review. Click OPEN DCL MENU to handle the clearance manually.

Runway type dialog

The assigned runway is not suitable for that aircraft type. Click OPEN DCL MENU to select a compatible runway.

Taxiway type dialog

The assigned holding point is not compatible with the aircraft type or category. Click ASSIGN HS to assign a suitable holding point.

CTOT dialog

The effective CTOT is more than 10 minutes in the future — the aircraft should hold at a holding point rather than push. Click ASSIGN HP to assign one.

Landing clearance dialog

The leading arrival on final or runway arrival has not been marked cleared to land. Click CLEAR TO LAND to confirm.


For datalink strip states and PDC flow, see Pre-departure clearance.