CPDLC+Procedures+for+Aircraft+Operators

EUROPEAN ORGANISATION FOR THE SAFETY OF AIR NAVIGATION

AIR / GROUND DATA LINK PROCEDURES FOR FLIGHTS

WITHIN THE AREA OF RESPONSIBILITY OF MAASTRICHT-UAC

Data link Procedures for Flights Maastricht-UAC

Edition : 2.5 Edition Date : 31. July 2008

© European Organisation for the Safety of Air Navigation (Eurocontrol) 2000. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of EUROCONTROL.

MAASTRICHT-UAC U.A.C. OPERATIONS DIVISION

SYSTEMS IMPLEMENTATION SECTION

DOCUMENT IDENTIFICATION SHEET

DOCUMENT DESCRIPTION

Document Title

Air / Ground Data link Procedures for Flights within

the Area of Responsibility of Maastricht-UAC

EDITION: 2.5

EDITION DATE: 31 July 2008

Abstract This Document provides the operating procedures, and additional background information and requirements, for flights conducting CPDLC with Maastricht-UAC during CPDLC operations.

Keywords Procedures, Manual, Data link; Uplinks, Downlinks, Voice Read back Requirement.

TEL: ++ 31 43 366 1510 Volker OPERATIONS AUTHOR : DIVISION:

SECTION: OASYS Stuhlsatz

DOCUMENT STATUS AND TYPE

STATUS CATEGORY CLASSIFICATION Working Draft Executive Task General Public Draft Specialist Task Restricted Proposed Issue Lower Layer Task Internal Use

Released Issue

ELECTRONIC BACK-UP

Procedures for Flights.DOC INTERNAL REFERENCE NAME : HOST SYSTEM MEDIA SOFTWARE(S)

Microsoft Windows™ Type: Hard disk Name: MS Word ™ Media Identification: Text processor Version: 97

DOCUMENT APPROVAL

AUTHORITY NAME AND SIGNATURE DATE

Author of the Document 28 January 2008 Volker STUHLSATZ

MANAGEMENT APPROVAL

AUTHORITY NAME AND SIGNATURE DATE

Resource and

Christopher ADAMS 28 January 2008 Planning Manager

Head of

Peter HENDRICKX 28 January 2008 Section

DOCUMENT CHANGE RECORD

The following table records the complete history of the successive editions of the present document.

EDITION DATE SECTIONS OR

REASON FOR CHANGE PAGES AFFECTED

0.1 13.08.03 Initial Draft for Procedures for Step 1 / Stage 2 all

0.2 18.08.03 Formatting changes and insertion of phraseology Section 5

1.0 22.10.03 Incorporating comments and amendments all

2.0 22.12.04 Final version for Stage 2 all

2.1 14.08.05 Addition of comment on log-on time/CPDLC connection

Pgs 11, 26

2.2 20.02.07 Revision of text concerning LACK timer and dialogue closure. Plus other minor text revisions

all

2.3 28 01.2008 Revision of text concerning new constraint menu including now also SPEED instructions

all

2.4 28 03.2008 Revision Voice Read back / WILCO prior to the execution of the profile changing DL instruction.

Section 5.1

2.5 30 07.2008 Revision all

REFERENCE DOCUMENTS

TITLE DATE EDITION

Table of contents

1. Acronyms....................................................................................................................... 7

2. Introduction .................................................................................................................. 9 2.1 Manual introduction.............................................................................................9 2.2 Context.................................................................................................................9 3. Physical environment ................................................................................................. 10 3.1 Date of operations ..............................................................................................10 3.2 Airspace .............................................................................................................10 3.3 Use of CPDLC ...................................................................................................10 3.4 Multi-stack .........................................................................................................10 3.5 Pre-flight identification......................................................................................10 3.6 Log-on address...................................................................................................10 3.7 Log-on time........................................................................................................11 3.8 Error: ACFT already LOGGED-ON .................................................................11 3.9 Callsign ..............................................................................................................11 4. Datalink Services ........................................................................................................ 12 4.1 Datalink Services Provided................................................................................12 4.2 DLIC – Datalink Initiation Capability ...............................................................12 4.3 ACM – ATC Communications Management ....................................................12 4.4 ACL – ATC Clearances And Instructions .........................................................12 4.5 AMC – ATC Microphone Check.......................................................................13 5. CPDLC PROCEDURES............................................................................................ 14 5.1 Execution of clearances .....................................................................................14 5.2 Operating Context / Strategic Use .....................................................................14 5.3 Supplemental communications ..........................................................................14 5.4 Precedence .........................................................................................................15 5.5 Uncertainty – revert to voice..............................................................................15 5.6 Replies................................................................................................................15 5.7 Validity of requests ............................................................................................15 5.8 Appropriate use..................................................................................................15 5.9 Emergencies.......................................................................................................15 5.10 Uplinked Clearances, Instructions and Responses .........................................16 5.10.1 Uplinks ........................................................................................................16 5.11 Downlinked Requests and Responses ............................................................20 5.11.1 Downlinks ...................................................................................................20 6. End-to-End System..................................................................................................... 24 6.1 End-to-End.........................................................................................................24 6.2 Ground system at Maastricht-UAC ...................................................................24 6.3 Communications Network .................................................................................24 6.4 Aircraft systems .................................................................................................25 6.4.1 Diagram ..........................................................................................................25 6.4.2 More................................................................................................................25 7. Log-on, connection and disconnection...................................................................... 26 7.1 flight plan information .......................................................................................26

7.2 Log-on................................................................................................................26 7.2.1 Log-on address ...............................................................................................26 7.2.2 Log-on time ....................................................................................................26 7.2.3 Callsign...........................................................................................................26 7.3 CPDLC enable ...................................................................................................27 7.3.1 CPDLC Initiation............................................................................................27 7.3.2 CPDLC Initiation Time ..................................................................................27 7.3.3 Current Data Authority...................................................................................28 7.3.4 CPDLC – only under control of Maastricht-UAC .........................................28 7.4 Inter- sector transfer...........................................................................................29 7.5 Next Data Authority...........................................................................................29 7.6 Inter-Centre transfer...........................................................................................30 8. Timeouts ...................................................................................................................... 31 8.1 Logical Acknowledgement – LACK .................................................................31 8.2 LACK Time .......................................................................................................31 8.3 LACK Time-out.................................................................................................31 8.3.1 System Behaviour...........................................................................................31 8.3.2 Controller Behaviour ......................................................................................31 8.4 Operational time-out ..........................................................................................31 8.4.1 System Behaviour...........................................................................................32 8.4.2 Controller Behaviour ......................................................................................32 8.5 Operational Time-Out - STANDBY Response From Crew............................32 9. Airborne Error Messages .......................................................................................... 32 9.1 Error Messages...................................................................................................32 10. Reporting..................................................................................................................... 33

ANNEX A............................................................................................................................... 34

Table of figures Figure 1 - Maastricht-UAC Ground System [simplified]........................................................... 25

.............................................................................. 27 Figure 2 - Log-on Request and Response................................................................................. 28 Figure 3 - CPDLC Connection and CDA

................................................................................................. 29 Figure 4 - Next Data Authority................................................................................... 30 Figure 5 - CONTACT and End Service

1. ACRONYMS ACARS Aircraft Communications Addressing and Reporting System ACL ATC Clearances and Instructions ACM ATC Communications Management AGDL Air Ground Data Link ALLA ATN Lower Layer Access AMC ATC Microphone Check ATC Air Traffic Control ATN Aeronautical Telecommunications Network ATS Air Traffic Services ATSU Air Traffic Services Unit CDA Current Data Authority CPC Controller Pilot Communications CPDLC Controller Pilot Data Link Communications DLIC Data link Initiation Capability DM Downlink message FAFEP FANS Front End Processor FANS Future Air Navigation System FDPS Flight Data Processing System FIR Flight Information Region FL Flight Level HF High Frequency [3-30 MHz] Id Identification [Flight] LACK Logical Acknowledgement MHz Megahertz NDA Next Data Authority NSSR Next Secondary Surveillance Radar [Code] Mode-A P2GW PETAL2 Gate Way PETAL Preliminary EUROCONTROL Trials of Air/ground Data link ROGER Message Received

[In specific CPDLC circumstances taken as WILCO] R/T Radio Telephony SATCOM Satellite Communication SIPR System Improvement and Problem Reporting [Form] SIS Systems Implementation Section SPI Special Position Indicator SSR Secondary Surveillance Radar [Code] UAC Upper Area Control UIR Upper [Flight] Information Region UM Uplink Message VCI Voice Change Instruction VHF Very High Frequency [30-300 MHz] WILCO Message Understood and Will Comply

Air / Ground Datalink Procedures for Flights 7

Intentionally Blank


2. INTRODUCTION

2.1 MANUAL INTRODUCTION This manual of ‘Air / Ground Data Link Procedures for Flights within the Area of Responsibility of Maastricht-UAC’ covers the procedures and requirements for aircraft using data link in airspace under the responsibility of Maastricht-UAC. This airspace includes:

Amsterdam FIR above FL245 •

•

Brussels UIR above FL245

• Hannover UIR above FL245 The manual also intends to provide, amongst other things, a brief, simplified description of the data link process, as employed in Maastricht-UAC. It is not intended as a full technical description. 2.2 CONTEXT Data link communications began to be used by Maastricht-UAC, under the Preliminary Eurocontrol Trials Air Ground Data Link trials. The initial PETAL trials started to be conducted in 1995. Though limited in scope, these first trials opened the doorway to the use of CPDLC in an operational environment, covering high-density traffic. Following the completion of PETAL, a second trial was put in place PETAL lI, which sought to push the boundaries of CPDLC use even further. It involved the use of CPDLC with multiple flights, operating across the sectors under Maastricht-UAC control. This second trial phase also involved the development of a multi-stack system in Maastricht-UAC, enabling controllers to communicate, via data link, with aircraft operating data link under different systems, NEAN, FANS or ATN. During the lifetime of PETAL, more than 10.000 successful CPDLC flights were recorded - flights where at least one successful CPDLC exchange took place. Particulars of the messages and services that will be used are contained in this manual. Pilot procedures, and expected behaviour, are detailed in this manual. Further details, if required, are available from Maastricht-UAC.

Intentionally Blank


3. PHYSICAL ENVIRONMENT 3.1 DATE OF OPERATIONS Maastricht-UAC implemented operational Controller/Pilot Data Link Communications – CPDLC - with effect from 18th June 2003 and is available on a 24/7 basis. 3.2 AIRSPACE Maastricht-UAC EDYY provides data link services in the following airspaces:

EHAA - Amsterdam FIR FL245 and above •

•

•

EBBU - Brussels UIR FL245 and above

EDVV - Hannover UIR FL245 and above

3.3 USE OF CPDLC The use of CPDLC in Maastricht-UAC airspace is not mandatory and conducted at the discretion of the controllers and aircrews involved. Aircrew are encouraged to use CPDLC to the maximum extend possible, as alternative communication means, also to ease the R/T frequency load. 3.4 MULTI-STACK Maastricht-UAC operates a multi-stack system. This means that Maastricht-UAC accept CPDLC exchanges with aircraft equipped with ATN or FANS. 3.5 PRE-FLIGHT IDENTIFICATION Maastricht-UAC requests that flights intending to conduct CPDLC exchanges with Maastricht-UAC enter tail number or 24-bit address code [as appropriate] in field 18 of their flight plans. 3.6 LOG-ON ADDRESS The log-on [ICAO facility] address for CPDLC communications with Maastricht-UAC is EDYY. Log-on to Maastricht covers the area of responsibility of Maastricht-UAC. Air / Ground Datalink Procedures for Flights 10

3.7 LOG-ON TIME Entering Maastricht UAC airspace LOG-ON can be established 15 to 45 minutes prior to entry. For departing aerodromes close or below to Maastricht-UAC airspace, LOG-ON may also be conducted already on the ground.

Pilots should be aware that CPDLC connection will not normally be attempted until the aircraft is within 10 minutes of the Maastricht boundary or above FL150 in case of departure flights to minimise cockpit distraction.

Note: The time parameter of ‘15 – 45 minutes prior to entry’ is to ensure interoperability with log-on in other CPDLC regions worldwide.

3.8 ERROR: ACFT ALREADY LOGGED-ON This Error message is generated when an aircraft has established DLIC (LOGON request down linked & LOGON response up linked) and then (whilst waiting for the CPC Start Request still to be uplink) the pilot tries to LOG ON again before CPDLC is established by the onboard CMU., due to a) message latency, FANS network may be subject to message delays and b) Maastricht-UAC Flight Server at will not uplink the CPC start request until an aircraft with DLIC is close to the Maastricht or above FL150.

3.9 CALLSIGN Aircraft should log-on using their current ICAO call sign – the call sign found on their flight plan (Mode-S Flight-ID) [e.g. BER23, not AB0023]. Crews should ensure that they do not use a two-letter IATA flight identification to log-on, as this will result in a failed log-on. Crew insertion of a leading zero [0] into a call sign will also result in a failed log-on. Note: The use of the correct call sign on LOG-ON is of paramount importance to the safety of air navigation, as a LOG-ON with a wrong call sign could lead to a misdirection of CPDLC messages.


4. DATALINK SERVICES

4.1 DATALINK SERVICES PROVIDED Maastricht-UAC provides the following data link services

DLIC •

•

•

•

ACM

ACL

AMC

4.2 DLIC – DATALINK INITIATION CAPABILITY DLIC, sometimes referred to as “logging on”, provides the mechanism for exchanging and forwarding information between aircraft and ground systems, in support of CPDLC, ADS, and CM communications. It also provides the necessary information to establish flight plan / address association in the ATC system, allowing the systems to ensure correct delivery of data link messages. It is a prerequisite to the operational data link services. 4.3 ACM – ATC COMMUNICATIONS MANAGEMENT From an operational point of view, the ACM service provides automated assistance to aircrew and controllers in transferring ATC communications from one sector/centre to another. It encompasses the transfer of all controller/aircrew communications, both R/T and data link. Aircrew can expect to receive data link instructions to contact their next voice frequency. 4.4 ACL – ATC CLEARANCES AND INSTRUCTIONS The ACL service enables the controller to issue en route clearances and instructions, and to reply to aircrew requests. The ACL service also enables the aircrew to make operational requests and to respond to clearances and instructions. Air / Ground Datalink Procedures for Flights 12

Aircrew requests in CPDLC operations with Maastricht-UAC are limited to the downlink of:

REQUEST DIRECT TO [position], REQUEST [level] REQUEST CLIMB TO [level] REQUEST DESCENT TO [level].

Other downlinks will be responded to by an ERROR message from ground. Important Note: Maastricht-UAC operates an environment in which profile changing CPDLC ATC clearances and instruction require – in addition to a data link operational response - voice read back by the aircrew, whilst others do not require the voice read back element. These requirements for aircrew responses are detailed in Section 5.10.1 and following subsections. Note: Particular vigilance shall be exercised by AIRBUS aircrews in order not to misinterpret old CPDLC message in the LOG with actual CPDLC clearances! 4.5 AMC – ATC MICROPHONE CHECK The AMC service provides controllers with the capability to uplink an instruction to aircraft to check that they are not inadvertently blocking a given voice frequency.


5. CPDLC PROCEDURES

5.1 EXECUTION OF CLEARANCES Maastricht-UAC operates an environment in which profile changing ATC clearances [direction, level] require – additionally to a data link operational response - voice read back by the aircrew. If a profile changing uplink is received the crew shall execute the clearance in the following manner:

• Firstly give VOICE READ BACK to ATC and send a WILCO response • Then comply with /execute the clearance

The above steps must be complied with in this order, in order to guarantee the correctness of the uplink clearance received prior to its execution. If a clearance or instruction is determined NOT to require voice read back then the crew shall execute the clearance in the following manner

• Send WILCO response and comply/execute the clearance/instruction. In either case, voice contact with ATC is required should any situation arise that prevents execution of a clearance following a WILCO response. These requirements for aircrew responses to the different ACL messages are detailed in Section 5.10.1 and following subsections.

5.2 OPERATING CONTEXT / STRATEGIC USE Data link CPDLC exchanges will be used in the context of routine, strategic situations only – the data link timeframe does not allow for their tactical use. Strategic in this sense refers to the ATC situation prevailing at the time. Strategic situations, in this context, are situations that allow for routine, non-time critical communications to take place between controllers and pilots. Tactical in this sense refers to the ATC situation prevailing at the time. Tactical situations, in this context, are ones where speed of delivery, and receipt of an aircrew response to an instruction, are of a time-critical nature in order to ensure the immediate safety of an aircraft. 5.3 SUPPLEMENTAL COMMUNICATIONS Data link will be used as a supplemental means of communication to voice. It is not the intention to replace voice as the primary means of communication in Maastricht-UAC airspace. Air / Ground Datalink Procedures for Flights 14

5.4 PRECEDENCE Voice communications and voice instructions shall have precedence over data link communications at all times. This means that a data link instruction may, if required, be over-ruled by a voice instruction. Voice remains the primary medium of communication in this airspace. 5.5 UNCERTAINTY – REVERT TO VOICE If uncertainty arises to either controllers or aircrew, about the content of a data link message, the application of a data link message, or the validity of a data link message, they must REVERT TO VOICE to clarify the situation. 5.6 REPLIES Wherever possible, CPDLC instructions and requests should be responded to using CPDLC. This is in addition to any voice read back requirements on the clearance or instruction. If a CPDLC message requiring a closure response is subsequently negotiated by voice, a CPDLC closure response message is still necessary to ensure the proper synchronisation of ground and aircraft systems. 5.7 VALIDITY OF REQUESTS Unless over-ruled by a subsequent voice instruction, a clearance given by data link has the same validity as one made by voice. A downlink request by data link has the same validity as one made by voice. 5.8 APPROPRIATE USE The operational utilisation of ATS over data link shall remain at all times under the control of the air traffic controllers and aircrew involved. If either believes that its use is inappropriate in the prevailing circumstances, then it should be suspended or terminated. 5.9 EMERGENCIES At present, CPDLC is generally not intended for use in emergency situations, where speed of delivery of messages can be a crucial element. Voice communication, if available, should be used as today, for emergency situations. Air / Ground Datalink Procedures for Flights 15

5.10 UPLINKED CLEARANCES, INSTRUCTIONS AND RESPONSES

5.10.1 UPLINKS The following uplink messages may be sent by controllers to aircrews conducting data link with Maastricht-UAC.

ATC Clearances Voice Read back Required

CLIMB TO [level] YES DESCEND TO [level] YES MAINTAIN [level] YES MAINTAIN [speed] YES MAINTAIN PRESENT [speed] YES MAINTAIN [speed] OR GREATER YES MAINTAIN [speed] OR LESS YES RESUME NORMAL SPEED YES CONTINUE PRESENT HEADING YES FLY HEADING [degrees] YES TURN [direction] [degrees] (Relative YES PROCEED DIRECT TO [position] YES

ATC Instructions Voice Read

back Required CONTACT [unit name] [frequency] NO SQUAWK [code] NO SQUAWK IDENT NO CHECK STUCK MICROPHONE [frequency] NO

ATC Replies to Downlink Requests

STANDBY UNABLE

5.10.1.1 Uplink Level Instructions ATC Level Clearances Voice Read

back Required CLIMB TO [level] YES DESCEND TO [level] YES MAINTAIN [level] YES

These clearances can be sent, either as clearances initiated by the controller, or as responses to requests from aircrew. Air / Ground Datalink Procedures for Flights 16

All Flight Level clearances as listed in the above table shall be read back by the aircrew. The read back phraseology is: “Call sign, confirming data link climb FL…” Following voice read back the aircrew shall then send a data link operational response to the message. The appropriate operational data link responses from an aircrew for these clearances are: WILCO / ACCEPT STANDBY UNABLE / REJECT If the operational response is WILCO the clearance shall be executed by the crew when the WILCO message is sent. Voice contact with ATC is required should any situation arise that prevents execution of a clearance following a WILCO response. If the operational response is UNABLE the crew’s inability to comply with the clearance shall be voiced on receipt of the clearance.

5.10.1.2 Uplink Route Instructions

ATC Route Clearances Voice Read back Required

CONTINUE PRESENT HEADING YES FLY HEADING [degrees] YES TURN [direction] [degrees] YES PROCEED DIRECT TO [position] YES

These clearances can be sent, either as clearances initiated by the controller, or as responses to requests from aircrew. All heading and route clearances as listed in the above table, shall be read back by the aircrew. The phraseology for read back is “Call sign, confirming data link turn ... ..” Following voice read back the aircrew shall then send a data link operational response to the message. The appropriate operational data link responses for these clearances are: Air / Ground Datalink Procedures for Flights 17

WILCO STANDBY UNABLE If the operational response is WILCO the clearance shall be executed by the crew when the WILCO message is sent. Voice contact with ATC is required should any situation arise that prevents execution of a clearance following a WILCO response. If the operational response is UNABLE the crew’s inability to comply with the clearance shall be voiced on receipt of the clearance. Note: For FANS aircraft – the implementation of the FLY HEADING [degrees] and the TURN [direction] [degrees] uplinks will present a ROGER option to the crew rather than a WILCO. After giving voice read back to ATC, aircrew selection and sending of a ROGER response in this instance is regarded as agreement from the crew that will also comply with the message – in effect it is used as a WILCO in these circumstances. Since no UNABLE response is available to either of these messages for FANS aircraft, in the event of a crew being unable to comply with a FLY HEADING or TURN up linked message having informed ATC by voice they should let the message time expire.

5.10.1.3 Uplink Contact Instruction – VCI

ATC Instructions Voice Read back Required

CONTACT [unit name] [frequency] NO This instruction can be sent, either to transfer an aircraft to another Maastricht-UAC sector or to an adjacent ATC unit. The transfer instructions will detail the R/T call sign and frequency of the next unit. The crew shall execute the change of frequency when the WILCO message is sent Aircrew must always initiate a voice contact with the given frequency after a Contact message has been received. There is no requirement for the crew to read back the instruction by voice prior to execution. Air / Ground Datalink Procedures for Flights 18

5.10.1.4 Uplink Squawk Instructions


SQUAWK [code] NO This instruction can be sent when there is a requirement to alter the current SSR code of an aircraft. The change of squawk shall be executed by the crew when the WILCO message is sent. There is no requirement on the crew to read back the instruction by voice prior to execution.

5.10.1.5 Uplink Squawk Ident. Instructions


SQUAWK IDENT [code] NO This instruction can be sent when there is a requirement to identify an aircraft, using the SPI feature. The SPI function shall be activated by the crew when the WILCO message is sent. There is no requirement on the crew to read back the instruction by voice prior to execution.

5.10.1.6 Uplink Check Stuck Microphone Instructions

ATC Instruction Voice Read back Required

CHECK STUCK MICROPHONE [frequency] NO This instruction can be sent by a controller in circumstances where an aircraft may be blocking the voice frequency inadvertently. When a FANS-equipped aircraft receives this message a data link ROGER response should be sent.


If the “Check Stuck Microphone [frequency]” message relates to the R/T frequency that an aircraft is currently using, then they should check that their radio equipment is not causing a ‘permanent transmission’. If the “Check Stuck Microphone [frequency]” message does not relate to the R/T frequency that an aircraft is using, then no action is required on the aircrew’s part.

5.10.1.7 ATC Replies to Downlink Requests

ATC Replies

CLEARANCE STANDBY UNABLE

Controller responses to down linked Route requests will either be by data link or by voice, depending on operational circumstances prevailing at the time. If ATC can comply with a downlink request by data link they will do so in the form of issuing a clearance to the aircraft. In addition to issuing clearances, ATC can also respond to a downlink request by using STANDBY or UNABLE. In the event of a controller responding by UNABLE the dialogue will be closed by the ground system. In the event of a controller responding STANDBY to a request a further operational response will follow. 5.11 DOWNLINKED REQUESTS AND RESPONSES 5.11.1 DOWNLINKS A limited number of downlink requests are available in Maastricht-UAC airspace. Although the following downlink messages may be used, downlink requests via CPDLC should be kept to a minimum. If, following a downlink request, an error is generated aircrew should reiterate the request by voice, not by CPDLC.


Aircrew Route Requests REQUEST [level] REQUEST CLIMB TO [level] REQUEST DESCENT TO [level] REQUEST DIRECT TO [position]

5.11.1.1 Downlink Level Requests

Aircrew Route Requests REQUEST [level] REQUEST CLIMB TO [level] REQUEST DESCENT TO [level]

These level messages may be transmitted by data link to request from the controller a change of level for the aircraft The controller has the ability to respond to these requests using either data link or voice.

5.11.1.2 Downlink Route Requests

Aircrew Route Requests REQUEST DIRECT TO [position]

This message may be transmitted to request from the controller a direct routing to a point. The controller has the ability to respond to these requests using either data link or voice.

5.11.1.3

5.11.1.4 Aircrew Responses

Aircrew Responses WILCO STANDBY UNABLE

Acceptable operational CPDLC responses to data link messages being used by Maastricht-UAC include: -


WILCO STANDBY UNABLE ROGER – See note. Note: For FANS aircraft a TURN or HEADING uplink message is converted to free text format by the Maastricht-UAC ground system prior to uplink. Avionics on FANS aircraft will present a ROGER [not WILCO] data link response to this free text uplink. Following voice read back of the clearance, when a ROGER response to these uplinks is sent, aircraft compliance with the instruction is required. Maastricht-UAC operates in a CPDLC environment in which uplinks that affect the profile of a flight [direction, level] require voice read back by the aircrew. This is in addition to a data link operational response. If responding WILCO to a profile-changing uplink message then the crew shall

• Firstly give voice read back of the clearance to ATC • Then send a WILCO response and comply with / execute the

clearance Note: The above steps must be complied with in this order, in order to guarantee the correctness of the uplink clearance received prior to its execution. If responding WILCO to a non-profile-changing uplink message then the crew shall

• Send a WILCO response and comply with / execute the clearance Following a WILCO response to an uplink, should circumstances arise that prevent execution of a clearance or instruction, voice contact should be made with ATC. In the event of an aircrew responding STANDBY to a data link message, then a further operational response is required from them to close the dialogue. If the operational response to a clearance or instruction is UNABLE the crew’s inability to comply with the clearance or instruction shall be voiced on receipt of the clearance/instruction. If an aircrew receives an “ERROR” response to an operational response sent by them, or a “Re-send” prompt on their crew interface, they should not re-send the CPDLC response, as they may only receive another “Error”. They should confirm their response to the clearance / message on R/T.


5.11.1.5 Free text On no account should FREETEXT be used by an aircrew, either to put a request, or in a response to an up linked message. If a FREETEXT message, or a message that is NOT supported by the ground environment is down linked, then the message ‘SERVICE UNAVAILABLE’ will be displayed to the crew. On receipt of a SERVICE UNAVAILABLE message, aircrew should contact ATC to clarify their request. Freeform FREETEXT messages are not implemented for controller use at MAS-UAC.


6. END-TO-END SYSTEM The description of the Maastricht-UAC data link system contained in this section is intended to be viewed as a simplified overview of the system. It is not intended as a detailed system specification. For a more detailed view of the system consult the PETAL End-to-End Specifications documentation. 6.1 END-TO-END The end-to-end system for using data link messaging at Maastricht-UAC can be divided into three parts The Ground System

The Communications Network

The Aircraft Systems

6.2 GROUND SYSTEM AT MAASTRICHT-UAC The data link ground system architecture at Maastricht-UAC is based on the existing Maastricht-UAC architecture, which relies on the current FDPS for most operational logic and functionality. The system supports different data link communications means – ATN and FANS– in a multi-stack environment. This means that Maastricht-UAC controllers can communicate with aircraft using either of these two technologies. It achieves this by providing a gateway [P2GW], external to the FDPS, which makes provision for the data channels and data exchange between the FDPS and the different communications networks. 6.3 COMMUNICATIONS NETWORK Data link messages between aircraft and the Maastricht-UAC controllers are channelled through commercial communications service providers. The service provider networks facilitate data exchanges for both ATN and FANS messages. Air / Ground Datalink Procedures for Flights 24

6.4 AIRCRAFT SYSTEMS Aircraft conducting CPDLC with Maastricht-UAC do so via certified ATN or FANS equipment. The type of equipment carried varies from airline to airline, and from airframe to airframe.

6.4.1 DIAGRAM A simplified overview of the system is provided in the diagram below.

CONTROLLER CONTROLLER CONTROLLER

MAASTRICHT-UAC FDPS

Gateway P2FEP

FAFEP ALLA [FANS] [ATN]

COMMUNICATIONS SERVICE PROVIDERS

AIRCRAFT

Figure 1 - Maastricht-UAC Ground System [simplified]

6.4.2 MORE More comprehensive explanation on the technical details is contained in PETAL End-to-End Specifications.


7. LOG-ON, CONNECTION AND DISCONNECTION

7.1 FLIGHT PLAN INFORMATION Maastricht-UAC requests that flights intending to conduct CPDLC exchanges with Maastricht-UAC enter tail number or 24-bit address code [as appropriate] in field 18 of their flight plans. 7.2 LOG-ON

7.2.1 LOG-ON ADDRESS The log-on address for CPDLC communications with Maastricht-UAC is EDYY. Log-on to Maastricht-UAC covers the entire working area of the Maastricht-UAC. Aircraft do not need to log-on separately into each Maastricht-UAC sector.

7.2.2 LOG-ON TIME Ideally log-on should be initiated 15 to 45 minutes prior to entry into Maastricht-UAC airspace. For aircraft departing from airports beneath, or in close proximity to, Maastricht-UAC airspace, log-on can be initiated on the ground. Note: The time parameter of ‘15 – 45 minutes prior to entry’ is to ensure interoperability with log-on in other CPDLC regions worldwide. Pilots should be aware that CPDLC connection will not normally be attempted until the aircraft is within 10 minutes of the Maastricht-UAC boundary – see Sections 7.3.1 and 7.3.2

7.2.3 CALLSIGN Aircraft should log-on using their ICAO call sign – the call sign found on their flight plan [e.g. BER23, not AB0023].. Crews should ensure that they do not use a two-letter IATA flight identification to log-on. This will result in a failed log-on. Crew insertion of a leading zero [0] into a call sign will also result in a failed log-on.


LOG-ON REQUEST

LOG-ON RESPONSE

E D Y Y

Figure 2 - Log-on Request and Response

7.3 CPDLC ENABLE

7.3.1 CPDLC INITIATION Following successful log-on and prior to entry into Maastricht-UAC the Maastricht-UAC ground system will initiate CPDLC connection. This is done in the form of a CPC Connect Request (CR1 for FANS) being sent to the aircraft. The aircraft response is in the form of a CPC Connect Confirm message (CC1 for FANS) to the ground system. This response is automatically generated by the avionics.

7.3.2 CPDLC INITIATION TIME Maastricht-UAC ground system will attempt CPDLC connection approximately 10 minutes prior to the entry of the aircraft into the airspace. For aircraft departing from airports beneath, or in close proximity to, Maastricht-UAC airspace, CPDLC connection will only occur above FL150. This is to ensure that crews are not distracted during busy periods of flight. If an aircraft logs-on from within Maastricht-UAC airspace CPDLC connection will occur as soon as log-on is complete Air / Ground Datalink Procedures for Flights 27

7.3.3 CURRENT DATA AUTHORITY Following CPDLC connection confirmation the Maastricht-UAC ground system will also automatically receive a CDA notification – Current Data Authority.

Note: This function is emulated by the Gateway for FANS aircraft. Current Data Authority is the notification for the receiving ATSU that the aircraft is ready to conduct CPDLC with that ATSU.

LOG-ON REQUEST

LOG-ON RESPONSE

E D Y Y

CPC CONNECT REQUEST

CPC CONNECT CONFIRM

C D A

Figure 3 - CPDLC Connection and CDA

7.3.4 CPDLC – ONLY UNDER CONTROL OF MAASTRICHT-UAC Whilst the log-on, CPDLC connection and CDA sequence will normally be conducted outside Maastricht-UAC airspace, an aircraft must be under the control of a Maastricht-UAC sector controller, before CPDLC exchanges can occur. Air initiated CPDLC messages should only be attempted when a flight is transferred to, and under the control of, Maastricht-UAC. Aircrew receive notification of the fact that they have come under the control of Maastricht-UAC when they receive an uplink.

CURRENT ATC UNIT EDYY MAASTRICHT-UAC CENTER Airborne attempts at CPDLC exchanges for flights not transferred to or under the control of Maastricht-UAC will result in errors being generated to the aircrew. Air / Ground Datalink Procedures for Flights 28

7.4 INTER- SECTOR TRANSFER Aircraft can be transferred via data link from one Maastricht-UAC sector to another Maastricht-UAC sector without the need for them to log-off and log-on repeatedly. Data link authority is transferred by the ground system to the appropriate sectors. 7.5 NEXT DATA AUTHORITY Although currently, Maastricht-UAC does not have external data link partners is the system set up to take account of future partnerships. Prior to leaving Maastricht-UAC airspace, an aircraft will automatically be up linked a Next Data Authority message [NDA] by the Maastricht-UAC ground system. The purpose of this message is to alert the aircraft to its next intended data link partner.

E D Y Y

N D A

Figure 4 - Next Data Authority


7.6 INTER-CENTRE TRANSFER Aircraft leaving Maastricht-UAC airspace are transferred via data link with a CONTACT Instruction. After a WILCO from the aircraft, CPDLC will be terminated with the aircraft. In the normal course of events no crew interaction is required to log-off from Maastricht-UAC.

Figure 5 - CONTACT and End Service

CPC END CONFIRM

E D Y Y

WILCO

CPC END REQUEST

N D A

‘CONTACT’ INSTRUCTION


8. TIMEOUTS The data link ground system in Maastricht-UAC employs several time-outs for messages. These time-outs are used to prevent data link messages becoming open-ended. 8.1 LOGICAL ACKNOWLEDGEMENT – LACK Some operational messages are sent to an aircraft that require avionics system verification of their arrival. This system verification of message receipt is referred to as a LACK, or Logical Acknowledgement. For FANS aircraft, the Message Assurance (MA) technical acknowledgement fulfils this role. 8.2 LACK TIME When an operational message that requires acknowledgement is sent, a timer is put into effect to receive a LACK from the aircraft (MA for FANS aircraft). The timer value for this technical response to be received by the Maastricht-UAC ground system is set at 30 seconds. 8.3 LACK TIME-OUT

8.3.1 SYSTEM BEHAVIOUR If the ground system does not receive a system response within 30 seconds it will alert the controller to that fact. The dialogue continues to remain open. 8.3.2 CONTROLLER BEHAVIOUR The controller will await the operational response or operational timeout.. 8.4 OPERATIONAL TIME-OUT After sending an operational message, a timer is put into effect to receive an operational response from the aircraft. (ie. WILCO, UNABLE, STANDBY) The timer value for this response to be received is set at 120 seconds.


8.4.1 SYSTEM BEHAVIOUR If the ground system does not receive an operational response within 120 seconds it will

Close the dialogue •

•

•

Warn the air traffic controller

If the ground system subsequently receives an operational response after 120 seconds it will

Issue an Error message to the aircrew If an aircrew receives an “ERROR” response to an operational response sent by them, or a “Re-send” prompt on their crew interface, they should not re-send the CPDLC response, as they may only receive another “Error”. They should confirm their response to the clearance / message on R/T. 8.4.2 CONTROLLER BEHAVIOUR On receipt of an operational time-out warning the controller will revert to voice to clarify the situation with the aircrew. 8.5 OPERATIONAL TIME-OUT - STANDBY RESPONSE FROM CREW If an aircrew responds to a data link message with a STANDBY, the timers for operational response are re-set. An operational response is then required from the crew no later than 60 seconds after a STANDBY has been sent

9. AIRBORNE ERROR MESSAGES 9.1 ERROR MESSAGES In the event of receiving an ‘ERROR’ message crews should revert to voice to clarify the operational situation with the controller. Crews should refrain from technical inquiries on the frequency with regard to possible reasons for provider aborts as controllers do normally not have any further information available. Air / Ground Datalink Procedures for Flights 32

10. REPORTING

CPDLC reports can be addressed to contact persons below, using the supplied form in Annex or any other agreed contact to Maastricht-UAC. Robert LONSDALE [email protected] DIV/Communication

Horsterweg 11, 6199 AC Maastricht-Airport, Netherlands Tel: +31 433 662 028

Volker STUHLSATZ [email protected] DIV/Operational and Airspace Systems

Horsterweg 11, 6199 AC Maastricht-Airport, Netherlands Tel: +31 433 661 510


mailto:[email protected]

mailto:[email protected]

ANNEX A

CPDLC Report – Flight Crew Data Link operations at Maastricht-UAC [EDYY]

Date: Time: Position:

C/S: ACFT Type: Registration:

24-Bit:

DL Provider: Hardware CMU/FMC: DL Mode:

Type of CPDLC event:

Airborne CPDLC LOG-ON failure

Unexpected CPDLC Provider abort (LOG-OFF)

Unexpected or Missing CPDLC message displayed

Erroneous CPDLC message received

Delayed CPDLC message receipt

Other (please specify problem in detail):

Was voice clarification need?

Which Error message was received?

Was expected CPDLC information missing?

How long was the delay of the CPDLC message?

Which abnormality was experienced?



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