777/787 'Message to Ground'
 

Can one downlink a message to any SITA address or does the addressee on the ground need something 'extra' to enable downlinked messages from aircraft to be received and read?

Can anyone that is able to receive a SITA message from a aircraft, then able to respond to that aircraft?

No information in the books about this, hence the question!

Cheers

SITA is a service, not a protocol. ARINC is another service provider.

SITA processes ACARS data for between the aircraft, airline operations centers, air traffic control, and aircraft/engine manufacturers..

There are plenty of ACARS receivers/decoders out there. Broadcast is entirely different matter.

In my experience there are certainly some station staff who claim that whilst they can receive air to ground messages in the airport office they are unable to reply. Now whether that is down to a genuine wiggly amps technical restriction or simply the station saving money by banning ground - air messages I'm afraid I do not know..

I know a little about SITA messages exchanged between airline offices and systems. They have a standard addressing format where :
CCC is the city or airport code
DD is the department code
YY is the airline code
For example JNBGGSA might be SAA's groups section in JNB.
Similarly, HDQRMAA is Sabre's main predesignated point for reservations traffic interchange, even though it's in DFW.

If the air<>ground codes are similarly formatted, I imagine that anyone who can send a SITA message to another airline would also be able to send one to an aircraft. However, I might be quite wrong, it's only a guess.

we can send and receive ACARS msg's from the ground through a program on our pc's. it can be sent to the printer or CDU in the flt deck, it can be addressed to specific a/c, and sent from the a/c to us prints directly to our tlx printer, we can also see all msgs's sent/received by the a/c.

My reason for asking is if you knew the SITA address of the destination and you had something worthwhile to pass on, it could be perhaps be beneficial to use this feature, (if it would work) rather than perhaps having to use the handling agents frequency instead during the last moments of the trip. Which can be a hit or a miss depending on the destination.

Yes it is possible, but depends on the setup of your on board equipment and operating software and restrictions enforced.

In one airline this is thus possible, in others it is not.

Ultimately, think of it as a message exchange method like an email server on the internet.
You can send and receive messages provided you are able to enter the correct address to send it to.
If you do not know the right address, the mail server bounces your message even though it was correctly sent from your device to the server for processing.
Similarly, if the server receives a message bound for you, it forwards it to you...

We don't need to know. The ACARS knows where the aircraft is going (from the flight number) so sends the message to all the correct adressess at destination.
We will always get a fuel message, if the crew stay on board, and the crew will request things every now and then, like an engineer, or a pax with a tight connection.