AIRAC AIP SUPPLEMENT TEL: 91-11-24632950 Extn: 2219/2233 AFS : VIDDYXAX FAX : 91-11-24615508 Email: gmais@aai.aero INDIA AERONAUTICAL INFORMATION SERVICE AIRPORTS AUTHORITY OF INDIA RAJIV GANDHI BHAVAN SAFDARJUNG AIRPORT NEW DELHI 110003 27/2012 12 JUL 2012 File No. AAI/ATM/AIS/09-09/2012 Following supplement is issued for information, guidance and necessary action. [EFFECTIVE DATE: 23 AUG 2012] V.P. AGRAWAL CHAIRMAN AIRPORTS AUTHORITY OF INDIA IMPLEMENTATION OF DATA LINK SERVICES i. DEPARTURE CLEARANCE (DCL) ii. DATA LINK AUTOMATIC TERMINAL INFORMATION SERVICE (D-ATIS) iii. DATA LINK METEOROLOGICAL INFORMATION FOR AIRCRAFT IN FLIGHT (D-VOLMET) 1. Introduction 1.1 Provision of Air Traffic Services, through data link, in the following functional areas is implemented to enhance ATM operational efficiency: i) Departure Clearance (DCL) services at Mumbai, Delhi, Kolkata, Chennai, Bangalore and Hyderabad; ii) D-ATIS messages from airports to be notified through NOTAM; iii) D-VOLMET messages from Mumbai and Kolkata airport. 1.2 The intent of this data link service is to provide an efficient and reliable DCL, D-ATIS and D-VOLMET services, thereby reducing the workload for both pilots and Air Traffic Controllers. 1.3 For those operators not participating in the data link service, ATC will continue to provide a standard R/T service for DCL on the notified VHF. 1.4 For those operators not participating in the data link service VOLMET service shall be available via notified HF. 1.5 The purpose of this publication is to familiarise users with requirements and operational procedures for the use of the data link services for DCL, D-ATIS and D-VOLMET. Airports Authority of India AIP Supplement 27/2012 Page 01 of 07
2. Brief Description of DCL, D-ATIS & D-VOLMET 2.1 Departure Clearance (DCL) also known as Pre Departure Clearance (PDC) 2.1.1 Using DCL, the pilot sends a Request for Departure Clearance Downlink (RCD) and receives a Departure Clearance Uplink (CLD) from ATC which contains the cleared destination, cleared runway, type of departure and route, squawk code, departure time, next frequency, current ATIS identifier. The pilot can then send back an acknowledgement: Departure Clearance Readback Downlink (CDA). 2.2 Data Link - Automatic Terminal Information Service (D-ATIS) 2.2.1 D-ATIS messages contain operational information required by aircraft before take-off and landing such as runway in use, current weather, airport and facility conditions. The pilot can downlink a message request (RAI) specifying the airport and whether the ATIS is required for Arrival (A), Departure (D), Arrival with automatic update (C) or En route (E). In return, the pilot receives an uplinked ATIS Report (DAI). A Flight Service Message (FSM) can be sent if the usual uplink ATIS Report is inappropriate or the D-ATIS Service is not available at the requested airport. 2.3 Data Link - Meteorological Information for Aircraft in Flight (D-VOLMET) 2.3.1 The D-VOLMET service enables the delivery of the VOLMET information to the cockpit in the text format through transmission of VOLMET information via data link. The D-VOLMET data-link service is also referred as En Route ATIS. 3. Operators Equipment Requirement 3.1 Aircraft equipped with Aircraft Communications Addressing and Reporting System (ACARS) equipment and compliant with AEEC 623 (Airlines Electronic Engineering Committee) may utilize DCL, D-ATIS and D-VOLMET over data link with connectivity to their airlines host computers via SITA Network. 4. D-ATIS and D-VOLMET Operating Procedure 4.1 An ATS DLS (ATS Data link Server) is installed at Mumbai to provide a D-ATIS data-link service for up to 255 airports. It provides a nationwide D-ATIS from a single ground system. 4.2 Every time new D-ATIS information is validated by the controller at airport having data link compatible D-ATIS equipment, the validated D-ATIS information is transmitted to the ATS DLS via AFTN network of Airports Authority of India. 4.3 The ATS DLS then builds its real-time ATIS database, and handles pilots data-link AEEC 623 compliant requests. The ATS DLS stores the D-ATIS and D-VOLMET in normalized real time databases based on Airport location, validity and change intent for ease in query/reply. 4.4 On receiving a D-ATIS/D-VOLMET request from aircraft, ATS DLS shall automatically query its real time database of D-ATIS and D-VOLMET bulletins to obtain the current bulletin for delivery to the aircraft through Data link. 4.5 The implementation of D-ATIS and D-VOLMET data-link services enables the pilots flying with an ACARS equipped aircraft to send ATIS requests and receive written ATIS information, using their on-board data link equipment (ACARS Management Unit). Airports Authority of India AIP Supplement 27/2012 Page 02 of 07
4.6 From his ACARS Unit, the pilot can easily request for ATIS Information, specifying the desired ICAO designator, as well as the type of ATIS Information (Departure/Arrival or En Route). 4.7 The AEEC 623/622 ATIS specification defines 5 types of ATIS requests (a request is also associated with a specific ICAO airport code defining the target approach): Request D : to request for Departure ATIS Request A : to request for Arrival ATIS Request E : to request for En route ATIS ( for D-VOLMET) Request C : to request for Continuous ATIS: with this request, the pilot receives automatically all ATIS updates during a certain time, or till the reception of a code T request. Request T : request to Terminate the Continuous ATIS. 4.8 Pilots flying data-link equipped aircraft may request the VOLMET information by sending ATIS en route requests for a specific location designated by the appropriate ICAO 4 letters code and receive printed VOLMET information, using their on-board data-link equipment (ACARS Management Unit), via the MCDU (Multipurpose Control and Display Unit). 4.9 D-ATIS/ D-VOLMET via data link system has the following benefits: Reduction of the pilots workload: D-ATIS/ D-VOLMET information is now available for the pilot in a printed format, without having to listen to the frequency and write down the entire information. Improved reliability: the data- link service eliminates the potential misunderstandings due to the poor quality of VHF voice. Enhanced accessibility: D-ATIS/ D-VOLMET information is available worldwide. Outside data-link VHF/HF coverage, the information can be accessed via satellite data- link. Improved ATIS information accuracy: The voice ATIS message can be updated more frequently, and the update contract of the data- link service enables the pilots to receive the ATIS information each time it is updated. 5. DCL Message Type 5.1 The AEEC DCL specification defines 4 types of DCL messages: RCD FSM CLD CDA Request for en-route Clearance Downlink Message of the pilot requesting an en-route clearance Flight System Uplink Message Automatic acknowledgement of receipt of RCD/CDA by the Air Traffic Control system, or the termination of the DCL service. Departure Clearance Uplink Message Issuance of the en-route clearance by the air traffic controller. Departure Clearance Readback Downlink Confirmation of en-route clearance by the pilot. Airports Authority of India AIP Supplement 27/2012 Page 03 of 07
6. DCL Operating Procedures 6.1 When using the DCL service, pilots shall maintain a listening watch on the frequency published for clearance delivery. In the event of any doubts or system-related difficulties, voice procedures shall be resumed. 6.2 A Pre-Departure Clearance issued by voice procedures always supersedes a predeparture clearance transmitted via the DCL service. 6.3 Prior to departure, both the pilot and the air traffic controller shall verify that the departure route assigned via the DCL service logically refers to the runway in use and to the route indicated in the current flight plan. In the event of any deviations or doubts, voice procedures shall be used. 6.4 After DCL is obtained pilot shall confirm via data link, and once the aircraft is ready for pushback/start-up, voice contact should be established with Clearance Delivery stating: With data link clearance ; QNH. POB 6.5 When instructed by Clearance Delivery, pilots shall immediately select and monitor Ground Frequency. 6.6 Current operational implementation does not include a re-issued clearance capability for any changes of runway, SID etc. Hence a revised Clarence shall only be obtained/delivered on VHF and the earlier clearance issued via data link will be cancelled. 6.7 To obtain the en-route clearance via the DCL service the pilot must execute the following steps: a) The pilot shall request the en-route clearance by means of an RCD message via his data link ACARS terminal not earlier than 20 minutes prior to the estimated off block time (EOBT) or 35 minutes prior to the calculated take-off time (CTOT). (Note: the data to be transmitted (e.g. airline code and aircraft type according to ICAO) shall correspond to the data contained in the current flight plan) b) The DCL ground system will check the received request and verify that it corresponds to an existing flight plan. The ground system will then send a positive or a negative request acknowledgment. As soon as the air traffic control system has received the RCD message, an FSM message will be transmitted automatically. If the RCD message is rejected by means of a negative FSM message, the pilot shall revert to voice procedures c) The controller uses his DCL terminal to issue the clearance, called CLD, which will be automatically sent to pilot via the ACARS data link network. The pilot can check and print the clearance at his convenience. Airports Authority of India AIP Supplement 27/2012 Page 04 of 07
d) A CLD message is also used to issue an en route clearance and to transmit the designator of the current ATIS broadcast, the CTOT available at the TWR and next frequency. e) A CLD contains: Clearance limit: airport of destination Standard Instrument Departure (SID) plus designated departure runway SSR-code. ATIS designator Additional departure instructions (if applicable) CTOT (if applicable) Free text f) The pilot shall acknowledge the en-route clearance by means of a CDA message. If the pilot does not transmit the CDA message within 5 minutes, the air traffic control system will automatically issue a negative FSM message together with the instruction to revert to voice procedures. Note: in order to ensure integrity between the pre-departure clearance (CLD) and the read back (CDA), the CDA message may not differ from the CLD message. The air traffic control system will not accept and process differing CDA messages. g) As soon as a CDA message is processed successfully, the air traffic control system will transmit a positive FSM message. Only when the FSM message has been received, the process is completely finished. Airports Authority of India AIP Supplement 27/2012 Page 05 of 07
Visualisation of DCL Procedures Airports Authority of India AIP Supplement 27/2012 Page 06 of 07
7. Example of Messages: RCD: FSM: RCD080 ABC0123 - VABB - GATE A09 VIDP ATIS W TYP/B747 FSM 1025 050707 VABB ABC0123 RCD RECEIVED REQUEST BEING PROCESSED CLD: CLD 1035 050707 VABB PDC 150 ABC0123 CLRD TO VIDP OFF 27 VIA ANOLI1A SQUAWK 7031 CTOT 1055 NEXT FREQ 121.9 ATIS W CDA: CDA 1035 050707 VABB PDC 150 ABC0123 CLRD TO VIDP OFF 27 VIA ANOLI1A SQUAWK 7031 CTOT 1055 NEXT FREQ 121.9 ATIS W FSM: Or Negative FSM: FSM 1035 050707 VABB ABC0123 CDA RECEIVED CLEARANCE CONFIRMED 8. Contact information FSM 1035 050707 VABB ABC0123 RCD REJECTED ERROR IN MESSAGE REVERT TO VOICE PROCEDURES 8.1 Airlines that intend to use the DCL service at Indian airports are requested to send the following information, before the first DCL operation, to the Executive Director (ATM) (Email: edatm@aai.aero) with the following information: - ACARS on-board equipment (Equipment manufacturer, type, and part number) and appropriate aircraft type(s). - ICAO and IATA designators for aircraft operating agencies. 9. Reference Documents: ED-89A: Data-link application system document for the ATIS Data-link service, Revision A (EUROCAE). ED 85A Data Link Application System Document for the Departure Clearance datalink service. ARINC Specification 620, Data Link Ground Systems Standard and Interface Specification (AEEC 620). ARINC Specification 622, ATS Data-link application over ACARS air-ground network (AEEC 622). ARINC Specification 623: Character Oriented ATS Application. (AEEC 623). Airports Authority of India AIP Supplement 27/2012 Page 07 of 07