Pre-departure clearances, or PDCs, are used at several ZLA airports. The benefit to using PDCs is that often-valuable frequency time is not wasted on transmitting a clearance to a pilot, and instead clearances are distributed via private message. PDCs can be used at BUR, LAS, LAX, ONT, SAN, SNA, and VNY.

The primary method to issue a PDC is using the virtual Tower Data Link Services. Pending flight plans are displayed in the top bar, labeled "DCL" for "Departure Clearance List." Click or use the keyboard commands to select an aircraft, and make adjustments if needed (NOTE: TDLS does NOT amend flight plans, if you need to make an amendment you must do so in the Flight Plan Editor and then re-select the aircraft. Most amendments should be issued as voice clearances to ensure they understood).

Once issued, the aircraft is shown in the lower-left list with the heading "PDC" to indicate they have received a one-way PDC.

In the future, TDLS may support CPDLC functionality, and those aircraft will be displayed on the lower-right side with their acknowledgement status. For more information on TDLS, view the documentation provided by vNAS.

If the TDLS system is malfunctioning, we have retained our legacy PDC aliases below:

Our alias file contains several PDC formats. Here's a guide on how to use them:

.pdcm (altitude) (departure sector ID) (ground sector ID)

This alias can be used when climb via SID phraseology is not utilized in a clearance. For example, .pdcm 3000 1A 2SG will transmit a clearance instructing an aircraft to maintain 3000 initially, that their departure control frequency is 124.5, and their ground control frequency is 121.75. If you are the departure controller and the ground controller, you can simply type .pdcm 3000. If you're working ground, then .pdcm 3000 1A will fill in 124.5 as the departure frequency, but your frequency will be listed as the ground control frequency.

.pdcv (departure sector ID) (ground sector ID)

Use this alias if an aircraft is on a departure procedure where climb via SID phraseology can be applied, and no intermediate altitude needs to be maintained. The same sector ID formatting as above can be applied here.

.pdcvx (altitude) (departure sector ID) (ground sector ID)

If an intermediate altitude on a procedure where climb via SID phraseology can be applied is required, use this alias. As with the .pdcm alias, type in the initial altitude, followed by sector IDs for the departure and ground controllers if applicable.

If you have made an amendment to the aircraft's route then add a "c" to the end of one of the above aliases (.pdcmc, .pdcvc, .pdcvxc). The PDC will then contain information that their routing has been changed.

Adding a u to the end of the PDC alias (after the c if a change is made) will issue a departure frequency of 122.8. This can be used for ground/tower controllers when an overlying radar controller is offline. .pdcmu, for example, will issue a departure frequency of 122.8 and allow the user to fill in an initial "maintain" instruction with the clearance.

.nopdc can be used if you are unable to transmit a PDC for any reason.