The Departure Clearance uplink message is generated as a character-oriented message. The Departure Clearance message can be received by the service provider from the airline or directly from the ATC agency depending on the
arrangements that have been negotiated.
The format of the Departure Clearance uplink message is consistent with the general form described in Section 4.3.5 of this Specification. ARINC Specification 623 contains the application data of the Departure Clearance uplink message If the character-oriented Departure Clearance uplink message is destined for the ACARS MU, it is received by the service provider as a ground/ground message with the SMI of ‘CLD’. The DSP translates this SMI to Label A3 in the air/ground uplink.
If the Departure Clearance message is for a peripheral, the appropriate SMI, Label (H1) and Sublabel are used. The MFI ‘A3’ is included at the beginning of the Supplemental Address field. Refer to Appendix D of Specification 622 for a listing.
Refer to the tables in Section 4.5.1 for an illustration of the message structure.