ACARS is a complex system which consists of several software mod ules which cooperate. Depending on whether you want to simulate an airplane or a dispatch/ATC station, you need another module.
The ACARS ATC client gives you a quite close implementation of CPDLC. The program has been modeled after the Australian system in cooperation with an Australian air traffic controller. It is meant for use with the ACARS network and a corresponding plane client.
Project Progress
2009-10-17 World Flight 2009 is coming up fast. As always, ACARS plays an important role in this event. Operationally it is used to coordinate many issues, and the maps it generates are very nice for event dissemination. There is more information online about how to use ACARS during WF2009.
2009-06-07 To facilitate nice maps for web sites of Virtual Airlines, I added a feature to the world map. You can now filter for all airplanes that share the prefix of a callsign, such as "BAW".
see all previous progress messages
Installation
Fetch the install file and run it. It will create a start icon for you.
The program comes up with a main window and announces that it successfully
read some messages and vocabularies. You have not entered your callsign yet,
so it will not try to reach the ACARS network. The coloured indicator at the
bottom right turns orange.
Open the File>Setup dialog box. Fill in your ATC callsign, for CPDLC this typically is a four-letter ICAO code such as 'YSSY'. Skip the logon code for now, press OK. Return to the main window. The program tries to connect to the ACARS Network every minute, but you can tell it to connect right now by clicking on the message area next to the coloured indicator. The message 'Illegal logon code' will appear and the indicator turns red. This sounds bad, but actually indicates that the whole network connection was completed successfully!
In order to receive a logon code, please mail the author. It may take a few hours before you get it. Logon codes are required to keep jokers and spammers out. When you get your code, enter it into the Setup box, and you will be greeted with a green indicator.
You can point the two file boxes at WAV files for event announcements. If a box is blank, a default sound will be used.
Operation
Just as with normal voice ATC, you don't need to do anything until a plane shows up.The Aircraft Lists
Via the View menu, you can open the Current Messages List and the
Planes Online List. These are pretty clear. Planes Online shows all planes
that are currently online, i.e., that you have received a message from and
that are still present on the network. Current Messages shows the list of
messages that still need your attention. By clicking on any line in these
windows, the relevant action is taken, which may vary according to the
situation.
In case no plane is online, these lists remain empty and you cannot do
anything. You can fake a plane online by typing its call sign in the entry
field of the Planes Online window and hitting Enter. This will temporarily
add a plane to the system so you have something to talk to.
The Message Compiler
This is the heart of the CPDLC system. With the Message Compiler you puzzle the instructions to the aircraft together. ATCACARS uses the Australian variant of the Message Compiler, and on purpose follows the real-life interface as closely as feasible (so don't complain if you don't like it!
).
Each message consists of up to five elements and each element may be selected from several groups of message elements. A message element may contain values. By clicking on a value, a window pops up that lets you change the value. When the message is complete, click 'Send to' and the instruction will be passed to the aircraft.
In some cases you might want to store a lengthy message for later sending. You can use the buttons "Save As (A, B, C)" and "Load (A, B, C)" for this.
The Telex Window
The Telex is actually not part of CPDLC as its main feature is to handle free-form text messages and CPDLC is all about fixed-form messages.
However more planes are equipped with telex-type ACARS only and there still are occasions where larger messages are better. A typical example is the pre-departure clearance. This is a message of up to eleven elements and CPDLC simply isn't big enough to carry it.
The telex window is constructed with large quantities of similar messages in mind, to cater for the typical PDC case for a busy airport area. Its operation is straightforward: incoming telexes on the left, outgoing on the right. You can copy a callsign from incoming to outgoing with the "Reply >>" button. Clicking on a previously sent message calls it back up, ready for editing and sending to another plane.
Connection Management
Planes first log on to an ATS unit using the 'request logon' message. ATC replies with 'logon accepted' or 'logon rejected'.ATC can transfer the plane to the next unit (sector) with the 'handover' message (COMMS). The plane will automatically switch to the next unit. Pilots do not need to notice or do anything.
ATC can terminate the CPDLC service with the 'logoff' message (COMMS). This should be done when the plane has left the area of competency of the ATS unit.