Introduction:
Within Santa Maria Oceanic Control Area (OCA), data link services for Air Traffic Control (ATC) purposes are available for suitable equipped aircraft. These services include FANS1/A functions as Automatic Dependent Surveillance Contracts (ADS-C) and Controller Pilot Data Link Communications (CPDLC).
FANS 1/A applications:
These applications will be available after the proper establishment of a logon to the Santa Maria OACC. ADS contracts and CPDLC connections are automatically initiated by ground systems after receiving the AFN logon initiated by flight crews or by automatic transfer from other ATS Unit.
ADS-C:
ADS-C is a data link service for use by Santa Maria OACC in which aircraft automatically transmits via an air-ground data link, aircraft position-related data derived from on-board navigation and position fixing systems. In IVAC we will assume aircraft equipped track as ADS-C track.
CPDLC:
Is a data link service that allows FANS 1/A equipped aircraft the exchange of data link messages between pilots and controllers. Communications can be conducted via a defined message element (a message element whose content and format are pre-determined) or via a free text message element, usually referred as a free-text message (a message element whose content is variable, i.e., composed by the sender). Pilots shall not use a free-text message if a standard message exists for the purpose of the required communication.
General requirements:
To use ADS-C/CPDLC aircraft must be FANS 1/A equipped.
Connection information for Santa Maria FIR data link services:
For ADS/CPDLC the logon address of Santa Maria OACC is the ICAO four letters designator LPPO.
General Procedures:
The backup system for the CPDLC service in the Santa Maria OCA is voice radio service provided by the Santa Maria Radio Station.
In order to assure that aircraft are always reachable via voice radio, flight crews shall always make a contact prior to the boundary with Santa Maria Radio Station to check the SELCAL and receive the frequencies allocation for the Santa Maria OCA and for the next ATS Unit, in accordance with flight crew procedures included in this document.
Flight crews should be aware that the requirements to establish successfully a CPDLC connection are different and depends from where the aircraft is entering the Santa Maria OAC airspace.
Entering from an airspace where CPDLC services are used:
Flights entering the Santa Maria OCA from airspace where CPDLC services are being received, such as Shanwick OAC, Gander OAC or New York OAC, do not need to perform another AFN logon, unless specified by any of those ATS Units, because the transfer of communications will occur automatically.
Entering from an airspace where CPDLC services are not used:
Flights entering the Santa Maria OCA from airspace where CPDLC services are not being received, such as Madrid ACC, Lisboa ACC, Canaries ACC, Sal ACC and Piarco ACC, should ensure that their ADS function is turned on and perform an AFN logon:
a) 15 to 45 minutes prior to entering the airspace; or
b) Prior to departure, for flights departing airports adjacent to or underlying the airspace.
Note: To avoid misunderstandings with oceanic clearance request procedures, flight crews are advised that they should verify the Portuguese AIP for the proper oceanic clearance request procedures, which may have different time requirements that should be complied independently from the participation on the CPDLC operational trials
Flight Crew
As stated before, flight crews shall contact the Santa Maria Radio Station on the proper or allocated HF or VHF frequencies prior to entering the Santa Maria OAC and identify the data link status of the aircraft using the term “CPDLC”.
Flight crews should continue to use the data link term “CPDLC” until either the selective calling system (SELCAL) check has been completed or the frequency assigment has been received.
On initial contact with the Santa Maria Radio Station the flight crews shall:
a) not include a position report;
b) use the data link term “CPDLC” after the aircraft call sign;
c) state the name of the next OCA or flight information region (FIR) to be entered; and
d) request the SELCAL check
– Example:
Santa Maria Radio, Airline 251, CPDLC
Airline 251, Santa Maria Radio, CPDLC, go ahead
Santa Maria, Airline 251, CPDLC, Next Shanwick, request SELCAL check ABCD
Airline 251, Santa Maria, CPDLC, Voice reports not required in LPPO, primary frequency 1234, secondary frequency 4567, next contact Shanwick on 1245, SELCAL ABCD coming up for check
Santa Maria, Airline 251, SELCAL received, out
Position Reporting
Flight crews are required to submit position reports via voice unless otherwise advised by Santa Maria Radio.
To reduce frequency congestion, when instructed ” VOICE REPORTS NOT REQUIRED IN SANTA MARIA OCA” flight crews should not send position reports via voice.
CPDLC flights that have been instructed “VOICE REPORTS NOT REQUIRED” are exempted from all routine voice meteorological reporting. Reports of unusual meteorological conditions such as severe turbulence should be made by voice to Santa Maria Radio. CPDLC should not be used for meteorological reports unless voice contact cannot be established.
Radio Station Procedures
On the initial contact with the Santa Maria Radio Station, flight crews should expect that the radio operator:
a) use the proper data link term after the aircraft call sign;
b) advise the flight crew that voice reports are not required in the Santa Maria OCA
c) allocate the primary and secondary frequencies to be used within the Santa Maria OAC;
d) provides the frequency or frequencies for the next OCA / FIR; and
e) perform the SELCAL check.
For other voice communications, flight crews should expect that radio operator will use the standard ICAO procedures for voice communications
Safety related issues:
Attention is called to flight crew that the use of data link services do not exempt the requirement of establishing voice communications with Santa Maria Radio at or before the FIR Boundary, whether on HF or VHF, even if a CPDLC connection is established.
To avoid misunderstandings in the communication process all communications initiated on CPDLC should be concluded via CPDLC and communications initiated via voice should also be concluded on voice. In cases of messages initiated via CPDLC that creates uncertainties or doubts the dialog should be terminated with UNABLE and a new dialog should be initiated via voice.