ESPAÑA

The purpose of this Aeronautical Information Circular is to inform aircraft operators of the D-ATIS and D-VOLMET service provision procedure to be followed.

1. INTRODUCTION

Due to the actual air traffic density and its estimated growth, it has been planned to provide ATIS and VOLMET automatically by means of a Data Link providing D-ATIS (Digital-ATIS) and D-VOLMET (Digital-VOLMET) services.

The D-ATIS and D-VOLMET services reiterate the analogue information provided by the ATIS (installed at different airports) and VOLMET (installed in centralised systems at Madrid ACC) equipment.

These means of communication enhances the quality of ATIS and VOLMET information, increasing its transmission and interpretation reliability. Especially when using data messages, the information transmitted is deemed easier to interpret and use than a voice message. The latter may be more susceptible to errors of interpretation or reception difficulties due to various sources of interference (poor frequency tuning, weather, etc.). Moreover, the correct use of data links reduces the workload of both pilots and ground operators.

1.1 Descripción y funciones del servicio D-ATIS

The D-ATIS service provides automatic assistance for requesting and providing air traffic information including: weather, operational procedures, runways and approach in use, and other information that may affect take-off, approach and landing phases, as well as ground operations.

The contents of the D-ATIS message are updated whenever the ATIS message changes, normally every 10 minutes, due to a change in weather and/or operational conditions affecting the ATIS information over this time period, as specified in the ICAO reference documentation.

A significant change in weather or a change in the operational environment will, at all times, generate new updated ATIS and D-ATIS messages, as is also specified in the ICAO reference documentation.

Consequently, the D-ATIS information requested and obtained shall be considered within the corresponding validity periods, taking into account changes in the active information that may occur from the time it is obtained until its specific operational use.

The D-ATIS service acts as a secondary resource to the ATIS-voice service, which transmits operational and weather information at the respective airports. All ATIS voice messages are also delivered by the D-ATIS via data link (e.g. arrival, departure and combined).

The ATIS message is received by the on-board flight crew via a VHF radio channel tuned to a certain frequency. The flight crew must listen to the entire recorded message until they reach the part of the information that is of interest to them. The ATIS message is continuously broadcast at aerodromes where this service is available.

In the case of D-ATIS, the flight crew reads the requested message and views it on the on-board data link display or MCDU (Multifunction Control Display Unit). They may also print it if their avionics support this functionality.

It is an operational requirement for the flight crew on board to obtain the ATIS information before contacting the ATS unit, as well as to confirm that they have correctly received the ATIS message. For verification, the flight crew must repeat the identifying letter of the ATIS message to the air traffic controller. Each individual ATIS message is cyclically assigned an identifying letter from the ICAO alphabet: Alpha to Zulu.

The operational contents of the ATIS message delivered by voice or data link must be semantically identical. The operational contents of the ATIS-voice message and of the D-ATIS data link are updated simultaneously.

The contents of the ATIS message are validated locally with information from each airport.

The D-ATIS service is provided at the explicit request of the aircraft, as opposed to the ATIS-voice service, which may be received by any aircraft tuning in to the specific frequency of the ATIS-voice system.

The D-ATIS service is initiated when the aircraft requests the service. There are two modes of ATIS requests:

• Demand mode – a single ATIS message is requested.
• Contract mode – an ATIS message and its updates are requested as and when they are generated.

The flight crew may make the request at any operational phase.

The D-ATIS message must be available during any operational phase of the flight

The D-ATIS Service is terminated by the on-board system after receiving one of the following messages:

• an ATIS message if the link is in "Demand mode".
• a rejection message (FSM).
• a D-ATIS contract cancellation message if the link is in "Contract mode".

The flight crew may request a D-ATIS message regardless of any other data link service.

Ultimately, the information provided by the controller shall prevail in the event of any discrepancy with the information provided by ATIS-voice and/or D-ATIS.

1.2 Description and functions of the D-VOLMET service.

The VOLMET service contains en-route weather information and operational information related to runway status that may or may not be included in METAR messages.

The VOLMET broadcasting areas in Spain and the METAR messages included in each of them are as follows:

This message is broadcast every 30 minutes or whenever there is an update to the information it contains.

The D-VOLMET service provides automatic assistance in requesting and providing weather information to en-route aircraft via data-link.

The D-VOLMET service acts as a secondary resource to the VOLMET-voice service.

The D-VOLMET message is updated each time the VOLMET-voice message is modified, i.e. when a SPECI message is received or when information is entered manually.

In any case, should the flight crew request weather information from the controller, the information provided by the controller shall prevail in the event of any discrepancy with the information provided by the VOLMET and/or D-VOLMET broadcast.

2. AREA OF APPLICATION

The area of application will be as follows:

• D-ATIS information: Applicable to all airports within Spanish airspace where ATIS service is provided.
• D-VOLMET information: Applicable to all Spanish airports and neighbouring ones as defined in the broadcast groups indicated in the documents ICAO 7754, EUR ANP FASID - Part V.II ATS-Table ATS 2 and ICAO 7474, AFI FASID ATM - Part V-Table ATS 2A.

3. OPERATIONAL CONSIDERATIONS REGARDING D-ATIS INFORMATION

3.1. ATS Security Considerations

In the event of discrepancies with the available ATIS/VOLMET information, the information broadcast via the ATIS-voice and VOLMET-voice systems respectively, shall prevail. It is reminded that this condition regarding the prevalence of the information shall be deemed to be in place until expressly stated otherwise in the appropriate and competent forums for this matter.

Consequently, if the ATIS-voice/VOLMET-voice information is not consistent with the D-ATIS/D-VOLMET information respectively, the latter shall be ignored by the pilots and airlines using these services.

In any case, the information provided by the air traffic controller shall prevail over any conflicting information provided by ATIS-voice, D-ATIS, VOLMET-voice and/or D-VOLMET.

3.2. Coordinating the D-ATIS/D-VOLMET service provision

The Participation Forms (see Annex A), and any other requests, issues or observations, should be addressed to:

ENAIRE – Sistemas Centrales de Navegación Aérea
DIRECCIÓN DE SISTEMAS
División de Comunicaciones
c/ Campezo, 1. Edificio 2.
Kudos Innovation Campus Las Mercedes
28022 Madrid (ESPAÑA)
Contact e-mail: solicitudes_datis_dvolmet@enaire.es

ANNEX A. Participation form for the provision of D-ATIS/D-VOLMET information