Section 3. Advanced Technologies and Oceanic Procedures (ATOP) - Oceanic Controller Pilot Data Link Communications (CPDLC)

14-3-1. MEANS OF COMMUNICATION

  1. When CPDLC is available and CPDLC connected aircraft are operating outside of VHF coverage, CPDLC must be used as the primary means of communication.
  2. Voice communications may be utilized for CPDLC aircraft when it will provide an operational advantage and/or when workload or equipment capabilities demand.
  3. When CPDLC is being utilized, a voice backup must exist (e.g., HF, SATCOM, Third Party).
  4. When a pilot communicates via CPDLC, the response should be via CPDLC.
  5. To the extent possible, the CPDLC message set should be used in lieu of free text messages.

14-3-2. TRANSFER OF COMMUNICATIONS TO THE NEXT FACILITY

  1. When the receiving facility is capable of CPDLC communications, the data link transfer is automatic and is accomplished within facility adapted parameters.
  2. When a receiving facility is not CPDLC capable, the transfer of communications must be made in accordance with local directives and Letters of Agreement (LOAs).

14-3-3. ABNORMAL CONDITIONS

  1. If any portion of the automated transfer fails, the controller should attempt to initiate the transfer manually. If unable to complete the data link transfer, the controller should advise the pilot to log on to the next facility and send an End Service (EOS) message.
  2. If CPDLC fails, voice communications must be utilized until CPDLC connections can be reestablished.
  3. If the CPDLC connection is lost on a specific aircraft, the controller should send a connection request message (CR1) or advise the pilot via backup communications to log on again.
  4. If CPDLC service is to be canceled, the controller must advise the pilot as early as possible to facilitate a smooth transition to voice communications. Workload permitting, the controller should also advise the pilot of the reason for the termination of data link.
  5. When there is uncertainty that a clearance was delivered to an aircraft via CPDLC, the controller must continue to protect the airspace associated with the clearance until an appropriate operational response is received from the flight crew. If an expected operational response to a clearance is not received, the controller will initiate appropriate action to ensure that the clearance was received by the flight crew. On initial voice contact with aircraft preface the message with the following:

    TBL 14-3-1
    Response Attribute of CPDLC Message Element

    Response Attribute

    Description

    For Uplink Message

    W/U

    Response required.

    Valid responses. WILCO, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if required), ERROR.

    NOTE– WILCO, UNABLE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY and ERROR will close the uplink message.

    FANS 1/A.— WILCO, UNABLE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

    A/N

    Response required.

    Valid responses. AFFIRM, NEGATIVE, STANDBY, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if required), ERROR

    NOTE– AFFIRM, NEGATIVE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY and ERROR will close the uplink message. FANS 1/A.— AFFIRM, NEGATIVE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

    R

    Response required.

    Valid responses. ROGER, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if required), ERROR.

    NOTE– ROGER, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY and ERROR will close the uplink message.

    FANS 1/A.— ROGER, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY. FANS 1/A aircraft do not have the capability to send UNABLE in response to an uplink message containing message elements with an “R” response attribute. For these aircraft, the flight crew may use alternative means to UNABLE the message. These alternative means will need to be taken into consideration to ensure proper technical and operational closure of the communication transaction.

    Y

    Response required.

    Valid responses: Any CPDLC downlink message, LOGICAL ACKNOWLEDGEMENT (only if required).

    N

    No response required unless logical acknowledgement is required.

    Valid Responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL ACKNOWLEDGEMENT, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY, ERROR.

    FANS 1/A.— “N” is defined as “no response is required,” but not used. Under some circumstances, an ERROR message will also close an uplink message.

    NE

    [Not defined in Doc 4444]

    FANS 1/A.— The WILCO, UNABLE, AFFIRM, NEGATIVE, ROGER, and STANDBY responses are not enabled (NE) for flight crew selection. An uplink message with a response attribute NE is considered to be closed even though a response may be required operationally. Under some circumstances, a downlink error message may be linked to an uplink message with a NE attribute.

    For Downlink Message

    Y

    Response required. Yes

    Valid responses. Any CPDLC uplink message, LOGICAL ACKNOWLEDGEMENT (only if required).

    N

    Response required. No, unless logical acknowledgement required.

    Valid responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL ACKNOWLEDGEMENT, SERVICE UNAVAILABLE, FLIGHT PLAN NOT HELD, ERROR

    FANS 1/A.— Aircraft do not have the capability to receive technical responses to downlink message elements with an “N” response attribute (other than LACK or ERROR for ATN B1 aircraft). In some cases, the response attribute is different between FANS 1/A aircraft and Doc 4444. As an example, most emergency messages have an “N” response attribute for FANS 1/A whereas Doc 4444 defines a “Y” response attribute for them. As a consequence, for FANS 1/A aircraft, ATC will need to use alternative means to acknowledge to the flight crew that an emergency message has been received.

    TBL 14-3-2
    Route Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM74

    (position)

    W/U

    Instruction to proceed directly to the specified position.

    UM75

    position

    NOTE– This message element is equivalent to SUPU-5 plus RTEU-2 in Doc 4444.

    W/U

    Instruction to proceed directly to the specified position.

    UM76

    AT (time) PROCEED DIRECT TO (position)

    W/U

    Instruction to proceed, at the specified time, directly to the specified position.

    UM77

    AT (position) PROCEED DIRECT TO (position)

    W/U

    Instruction to proceed, at the specified position, directly to the next specified position.

    UM78

    AT (altitude) PROCEED DIRECT TO (position)

    W/U

    Instruction to proceed upon reaching the specified altitude, directly to the specified position.

    UM79

    CLEARED TO (position) VIA (route clearance)

    W/U

    Instruction to proceed to the specified position via the specified route.

    UM80

    (route clearance)

    W/U

    Instruction to proceed via the specified route.

    UM83

    AT (position) CLEARED (route clearance)

    W/U

    Instruction to proceed from the specified position via the specified route.

    UM85

    route clearance

    R

    Notification that a clearance to fly on the specified route may be issued.

    UM86

    AT (position) EXPECT (route clearance)

    R

    Notification that a clearance to fly on the specified route from the specified position may be issued.

    UM87

    position

    R

    Notification that a clearance to fly directly to the specified position may be issued.

    UM88

    AT (position) EXPECT DIRECT TO (position)

    R

    Notification that a clearance to fly directly from the first specified position to the next specified position may be issued.

    UM89

    AT (time) EXPECT DIRECT TO (position)

    R

    Notification that a clearance to fly directly to the specified position commencing at the specified time may be issued.

    UM90

    AT (altitude) EXPECT DIRECT TO (position)

    R

    Notification that a clearance to fly directly to the specified position commencing when the specified altitude is reached may be issued.

    UM93

    time

    R

    Notification that an onwards clearance may be issued at the specified time.

    UM99

    procedure name

    NOTE– Used when a published procedure is designated.

    R

    Notification that a clearance may be issued for the aircraft to fly the specified procedure or clearance name.

    UM137

    CONFIRM ASSIGNED ROUTE

    NOTE– NE response attribute.

    NE

    Request to confirm the assigned route.

    UM147

    REQUEST POSITION REPORT

    NE

    Request to make a position report.

    TBL 14-3-3
    Route Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM22

    REQUEST DIRECT TO (position)

    Y

    Request for a direct clearance to the specified position.

    DM23

    procedure name

    Y

    Request for the specified procedure or clearance name.

    DM24

    route clearance

    Y

    Request for the specified route.

    DM25

    REQUEST CLEARANCE

    Y

    Request for the specified clearance.

    DM26

    REQUEST WEATHER DEVIATION TO (position) VIA (route clearance)

    Y

    Request for a weather deviation to the specified position via the specified route.

    DM40

    route clearance

    N

    Confirmation that the assigned route is the specified route.

    DM48

    position report

    N

    Position report.

    DM51

    WHEN CAN WE EXPECT BACK ON ROUTE

    Y

    Request for the time or position that can be expected to rejoin the cleared route.

    DM70

    degrees

    Y

    Request for the specified heading.

    DM71

    degrees

    Y

    Request for the specified ground track.

    TBL 14-3-4
    Lateral Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM64

    OFFSET (distance offset) (direction) OF ROUTE

    W/U

    Instruction to fly a parallel track to the cleared route at a displacement of the specified distance in the specified direction.

    UM65

    AT (position) OFFSET (distance offset) (direction) OF ROUTE

    W/U

    Instruction to fly a parallel track to the cleared route at a displacement of the specified distance in the specified direction and commencing at the specified position.

    UM66

    AT (time) OFFSET (distance offset) (direction) OF ROUTE

    W/U

    Instruction to fly a parallel track to the cleared route at a displacement of the specified distance in the specified direction and commencing at the specified time.

    UM67

    PROCEED BACK ON ROUTE

    W/U

    Instruction to rejoin the cleared route.

    UM68

    position

    W/U

    Instruction to rejoin the cleared route before passing the specified position.

    UM69

    time

    W/U

    Instruction to rejoin the cleared route before the specified time.

    UM70

    position

    W/U

    Notification that a clearance may be issued to enable the aircraft to rejoin the cleared route before passing the specified position.

    UM71

    time

    W/U

    Notification that a clearance may be issued to enable the aircraft to rejoin the cleared route before the specified time.

    UM72

    RESUME OWN NAVIGATION

    W/U

    Instruction to resume own navigation following a period of tracking or heading clearances. May be used in conjunction with an instruction on how or where to rejoin the cleared route.

    UM82

    CLEARED TO DEVIATE UP TO (distance offset) (direction) OF ROUTE

    W/U

    Instruction allowing deviation up to the specified distance(s) from the cleared route in the specified direction(s).

    UM98

    IMMEDIATELY TURN (direction) HEADING (degrees)

    NOTE– This message element is equivalent to EMGU-2 plus LATU-11 in Doc 4444.

    W/U

    Instruction to turn left or right as specified on to the specified heading.

    UM127

    REPORT BACK ON ROUTE

    NOTE– R response attribute.

    W/U

    Instruction to report when the aircraft is back on the cleared route.

    UM130

    position

    NOTE– R response attribute.

    W/U

    Instruction to report upon passing the specified position.

    UM132

    CONFIRM POSITION

    NE

    Instruction to report the present position.

    UM138

    CONFIRM TIME OVER REPORTED WAYPOINT

    NE

    Instruction to confirm the previously reported time over the last reported waypoint.

    UM139

    CONFIRM REPORTED WAYPOINT

    NE

    Instruction to confirm the identity of the previously reported waypoint.

    UM140

    CONFIRM NEXT WAYPOINT

    NE

    Instruction to confirm the identity of the next waypoint.

    UM141

    CONFIRM NEXT WAYPOINT ETA

    NE

    Instruction to confirm the previously reported estimated time at the next waypoint.

    UM142

    CONFIRM ENSUING WAYPOINT

    NE

    Instruction to confirm the identity of the next plus one waypoint.

    UM145

    CONFIRM HEADING

    NE

    Instruction to report the present heading.

    UM146

    REPORT GROUND TRACK

    NE

    Instruction to report the present ground track.

    UM152

    WHEN CAN YOU ACCEPT (specified distance) (direction) OFFSET

    NE

    Instruction to report the earliest time when the specified offset track can be accepted.

    TBL 14-3-5
    Lateral Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM15

    REQUEST OFFSET (specified distance) (direction) OF ROUTE

    Y

    Request for a parallel track from the cleared route at a displacement of the specified distance in the specified direction.

    DM16

    AT (position) REQUEST OFFSET (specified distance) (direction) OF ROUTE

    Y

    Request that a parallel track, offset from the cleared track by the specified distance in the specified direction, be approved from the specified position.

    DM17

    AT (time) REQUEST OFFSET (specified distance) (direction) OF ROUTE

    Y

    Request that a parallel track, offset from the cleared track by the specified distance in the specified direction, be approved from the specified time.

    DM27

    REQUEST WEATHER DEVIATION UP TO (specified distance) (direction) OF ROUTE

    Y

    Request for a weather deviation up to the specified distance(s) off track in the specified direction(s).

    DM31

    position

    N

    Report indicating passing the specified position.

    DM33

    position

    N

    Notification of the present position.

    DM35

    degrees

    N

    Notification of the present heading in degrees.

    DM36

    degrees

    N

    Notification of the present ground track in degrees.

    DM41

    BACK ON ROUTE

    N

    Report indicating that the cleared route has been rejoined.

    DM42

    position

    N

    The next waypoint is the specified position.

    DM43

    time

    N

    The ETA at the next waypoint is as specified.

    DM44

    position

    N

    The next plus one waypoint is the specified position.

    DM45

    position

    N

    Clarification of previously reported waypoint passage.

    DM46

    time

    N

    Clarification of time over previously reported waypoint.

    DM59

    DIVERTING TO (position) VIA (route clearance)

    NOTE 1. – H alert attribute.

    NOTE 2. – N response attribute.

    N

    Report indicating diverting to the specified position via the specified route, which may be sent without any previous coordination done with ATC.

    DM60

    OFFSETTING (distance offset) (direction) OF ROUTE

    NOTE 1. – H alert attribute.

    NOTE 2. – N response attribute.

    N

    Report indicating that the aircraft is offsetting to a parallel track at the specified distance in the specified direction off from the cleared route.

    DM80

    DEVIATING (deviation offset) (direction) OF ROUTE

    NOTE 1. – H alert attribute.

    NOTE 2. – N response attribute.

    N

    Report indicating deviating specified distance or degrees in the specified direction from the cleared route.

    DM67

    WE CAN ACCEPT (direction) (distance offset) AT (time)

    N

    We can accept a parallel track offset the specified distance in the specified direction at the specified time.

    DM67

    WE CANNOT ACCEPT (direction) (distance offset)

    N

    We cannot accept a parallel track offset the specified distance in the specified direction.

    DM67

    altitude

    N

    We cannot accept the specified altitude.

    TBL 14-3-6
    Altitude Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM6

    (altitude)

    R

    Notification that an altitude change instruction should be expected.

    UM7

    (time)

    R

    Notification that an instruction may be expected for the aircraft to commence climb at the specified time.

    UM8

    position

    R

    Notification that an instruction may be expected for the aircraft to commence climb at the specified position.

    UM9

    time

    R

    Notification that an instruction may be expected for the aircraft to commence descent at the specified time.

    UM10

    position

    R

    Notification that an instruction may be expected for the aircraft to commence descent at the specified position.

    UM11

    (time)

    R

    Notification that an instruction should be expected for the aircraft to commence cruise climb at the specified time.

    UM12

    position

    R

    Notification that an instruction should be expected for the aircraft to commence cruise climb at the specified position.

    UM13

    AT (time) EXPECT CLIMB TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence climb at the specified time to the specified altitude.

    UM14

    AT (position) EXPECT CLIMB TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence climb at the specified position to the specified altitude.

    UM15

    AT (time) EXPECT DESCENT TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence descent at the specified time to the specified altitude.

    UM16

    AT (position) EXPECT DESCENT TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence descent at the specified position to the specified altitude.

    UM17

    AT (time) EXPECT CRUISE CLIMB TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence cruise climb at the specified time to the specified altitude.

    UM18

    AT (position) EXPECT CRUISE CLIMB TO (altitude)

    R

    Notification that an instruction should be expected for the aircraft to commence cruise climb at the specified position to the specified altitude.

    UM19

    (altitude)

    W/U

    Instruction to maintain the specified altitude.

    UM20

    (altitude)

    W/U

    Instruction that a climb to the specified altitude is to commence and once reached is to be maintained.

    UM21

    AT (time) CLIMB TO AND MAINTAIN (altitude)

    W/U

    Instruction that at the specified time a climb to the specified altitude is to commence and once reached is to be maintained.

    NOTE– This message element would be preceded with uM19 MAINTAIN (altitude) to prevent the premature execution of the instruction.

    UM22

    AT (position) CLIMB TO AND MAINTAIN (altitude)

    W/U

    Instruction that at the specified position a climb to the specified altitude is to commence and once reached is to be maintained.

    NOTE– This message element would be preceded with uM19 MAINTAIN (altitude) to prevent the premature execution of the instruction.

    UM23

    (altitude)

    W/U

    Instruction that a descent to the specified altitude is to commence and once reached is to be maintained.

    UM24

    AT (time) DESCEND TO AND MAINTAIN (altitude)

    W/U

    Instruction that at the specified time a descent to the specified altitude is to commence and once reached is to be maintained.

    UM25

    AT (position) DESCEND TO AND MAINTAIN (altitude)

    W/U

    Instruction that at the specified position a descent to the specified altitude is to commence and once reached is to be maintained.

    UM26

    CLIMB TO REACH (altitude) BY (time)

    W/U

    Instruction that a climb is to be completed such that the specified altitude is reached before the specified time.

    UM27

    CLIMB TO REACH (altitude) BY (position)

    W/U

    Instruction that a climb is to be completed such that the specified altitude is reached before passing the specified position.

    UM28

    DESCEND TO REACH (altitude) BY (time)

    W/U

    Instruction that a descent is to be completed such that the specified altitude is reached before the specified time.

    UM29

    DESCEND TO REACH (altitude) BY (position)

    W/U

    Instruction that a descent is to be completed such that the specified altitude is reached before passing the specified position.

    UM30

    MAINTAIN BLOCK (altitude) TO (altitude)

    W/U

    Instruction to maintain the specified vertical range.

    UM31

    CLIMB TO AND MAINTAIN BLOCK

    W/U

    Instruction that a climb to the specified vertical range is to commence and once reached is to be maintained.

    UM32

    DESCEND TO AND MAINTAIN BLOCK (altitude) TO (altitude)

    W/U

    Instruction that a descent to the specified vertical range is to commence and once reached is to be maintained.

    UM33

    altitude

    Instruction that authorizes a pilot to conduct flight at any altitude from the minimum altitude up to and including the altitude specified in the clearance. Further, it is approval for the pilot to proceed to and make an approach at the destination airport.

    UM34

    altitude

    W/U

    A cruise climb is to commence and continue until the specified altitude is reached.

    UM35

    altitude

    W/U

    A cruise climb can commence once above the specified altitude.

    UM36

    altitude

    W/U

    Instruction that a climb to the specified altitude or vertical range is to commence and once reached is to be maintained.

    UM37

    (altitude)

    W/U

    Instruction that a descent to the specified altitude or vertical range is to commence and once reached is to be maintained.

    UM38

    altitude

    W/U

    Instruction that a climb to the specified altitude or vertical range is to commence and once reached is to be maintained.

    UM39

    altitude

    W/U

    Instruction that a descent to the specified altitude or vertical range is to commence and once reached is to be maintained.

    UM40

    altitude

    W/U

    Urgent instruction to immediately stop a climb once the specified altitude is reached.

    UM41

    altitude

    W/U

    Urgent instruction to immediately stop a descent once the specified altitude is reached.

    UM128

    altitude

    NOTE– R response attribute.

    W/U

    Instruction to report upon leaving the specified altitude.

    UM129

    altitude

    NOTE– R response attribute.

    W/U

    Instruction to report upon maintaining the specified altitude.

    UM133

    CONFIRM ALTITUDE

    NE

    Instruction to report the present altitude.

    UM135

    CONFIRM ASSIGNED ALTITUDE

    NOTE– NE response attribute.

    NE

    Request to confirm the assigned altitude.

    UM148

    altitude

    NOTE– NE response attribute.

    NE

    Request for the earliest time or position when the specified altitude can be accepted.

    UM149

    CAN YOU ACCEPT (altitude) AT (position)

    A/N

    Request to indicate whether or not the specified altitude can be accepted at the specified position.

    UM150

    CAN YOU ACCEPT (altitude) AT (time)

    A/N

    Request to indicate whether or not the specified altitude can be accepted at the specified time.

    UM171

    vertical rate

    W/U

    Instruction to climb at the specified rate or greater.

    UM172

    vertical rate

    W/U

    Instruction to climb at the specified rate or less.

    UM173

    vertical rate

    W/U

    Instruction to descend at the specified rate or greater.

    UM174

    vertical rate

    W/U

    Instruction to descend at the specified rate or less.

    UM175

    altitude

    R

    Instruction to report when the aircraft has reached the specified altitude.

    NOTE– To be interpreted as “Report reaching an assigned altitude.”

    UM177

    AT PILOTS DISCRETION

    N

    Used in conjunction with a clearance or instruction to indicate that the pilot may execute when prepared to do so.

    UM180

    REACHING BLOCK (altitude) TO (altitude)

    NOTE– R response attribute.

    W/U

    Instruction to report upon reaching the specified vertical range.

    TBL 14-3-7
    Altitude Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM6

    (altitude)

    Y

    Request to fly at the specified altitude.

    DM7

    REQUEST BLOCK (altitude) TO (altitude)

    Y

    Request to fly at the specified vertical range.

    DM8

    altitude

    Y

    Request to cruise climb to the specified altitude.

    NOTE– Due to different interpretations between the various ATS units, this element should be avoided.

    DM9

    (altitude)

    Y

    Request for a climb to the specified altitude or vertical range.

    DM10

    (altitude)

    Y

    Request for a descent to the specified altitude or vertical range.

    DM11

    AT (position) REQUEST CLIMB TO (altitude)

    Y

    Request for a climb/descent to the specified altitude to commence at the specified position.

    DM12

    AT (position) REQUEST DESCENT TO (altitude)

    Y

    Request for a climb/descent to the specified altitude to commence at the specified position.

    DM13

    AT TIME (time) REQUEST CLIMB TO (altitude)

    Y

    Request for a climb/descent to the specified altitude to commence at the specified time.

    DM14

    AT TIME (time) REQUEST DESCENT TO (altitude)

    Y

    Request for a climb/descent to the specified altitude to commence at the specified time.

    DM28

    altitude

    N

    Notification of leaving the specified altitude.

    DM29

    altitude

    N

    Report indicating climbing to the specified altitude.

    DM30

    altitude

    NOTE– N alert attribute.

    N

    Notification of descending to the specified altitude.

    DM32

    altitude

    N

    Notification of the present altitude.

    DM37

    altitude

    N

    Report indicating that the specified altitude is being maintained.

    DM38

    (altitude)

    N

    Confirmation that the assigned altitude is the specified altitude or vertical range.

    DM52

    WHEN CAN WE EXPECT LOWER ALTITUDE

    Y

    Request for the earliest time or position that a descent can be expected.

    DM53

    WHEN CAN WE EXPECT HIGHER ALTITUDE

    Y

    Request for the earliest time or position that a climb can be expected.

    DM54

    altitude

    Y

    Request for the earliest time at which a clearance to cruise climb to the specified altitude can be expected.

    DM61

    (altitude)

    NOTE– Urgent alert attribute.

    N

    Report indicating descending to the specified altitude.

    DM67

    ‘WE CAN ACCEPT (altitude) AT TIME (time)’

    N

    We can accept the specified altitude at the specified time.

    DM67

    ‘WE CANNOT ACCEPT (altitude)’

    N

    Indication that the specified altitude cannot be accepted.

    DM67

    ‘WHEN CAN WE EXPECT CLIMB TO (altitude)’

    N

    Request for the earliest time at which a clearance to climb to the specified altitude can be expected.

    DM67

    ‘WHEN CAN WE EXPECT DESCENT TO (altitude)’

    N

    Request for the earliest time at which a clearance to descend to the specified altitude can be expected.

    DM72

    altitude

    N

    Notification that the aircraft has reached the specified altitude.

    DM75

    AT PILOTS DISCRETION

    N

    Used in conjunction with another message to indicate that the pilot wishes to execute the request when the pilot is prepared to do so.

    DM76

    REACHING BLOCK (altitude) TO (altitude)

    N

    Report indicating reaching the specified vertical range.

    DM77

    ASSIGNED BLOCK (altitude) TO (altitude)

    NOTE– Used for a vertical range.

    N

    Confirmation that the assigned vertical range is the specified vertical range.

    TBL 14-3-8
    Crossing Constraint Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM42

    EXPECT TO CROSS (position) AT (altitude)

    R

    Notification that a altitude change instruction should be expected which will require the specified position to be crossed at the specified altitude.

    UM43

    EXPECT TO CROSS (position) AT OR ABOVE (altitude)

    R

    Notification that a altitude change instruction should be expected which will require the specified position to be crossed at or above the specified altitude.

    UM44

    EXPECT TO CROSS (position) AT OR BELOW (altitude)

    R

    Notification that a altitude change instruction should be expected which will require the specified position to be crossed at or below the specified altitude.

    UM45

    EXPECT TO CROSS (position) AT AND MAINTAIN (altitude)

    R

    Notification that a altitude change instruction should be expected which will require the specified position to be crossed at the specified altitude which is to be maintained subsequently.

    UM46

    CROSS (position) AT (altitude)

    W/U

    Instruction that the specified position is to be crossed at the specified altitude.

    UM47

    CROSS (position) AT OR ABOVE (altitude)

    W/U

    Instruction that the specified position is to be crossed at or above the specified altitude.

    UM48

    CROSS (position) AT OR BELOW (altitude)

    W/U

    Instruction that the specified position is to be crossed at or below the specified altitude.

    UM49

    CROSS (position) AT AND MAINTAIN (altitude)

    W/U

    Instruction that the specified position is to be crossed at the specified altitude.

    UM50

    CROSS (position) BETWEEN (altitude) AND (altitude)

    W/U

    Instruction that the specified position is to be crossed within the specified vertical range.

    UM51

    CROSS (position) AT (time)

    W/U

    Instruction that the specified position is to be crossed at the specified time.

    UM52

    CROSS (position) AT OR BEFORE (time)

    W/U

    Instruction that the specified position is to be crossed before the specified time.

    UM53

    CROSS (position) AT OR AFTER (time)

    W/U

    Instruction that the specified position is to be crossed after the specified time.

    UM54

    CROSS (position) BETWEEN (time) AND (time)

    W/U

    Instruction that the specified position is to be crossed between the specified times.

    UM55

    CROSS (position) AT (speed)

    W/U

    Instruction that the specified position is to be crossed at the specified speed.

    UM56

    CROSS (position) AT OR LESS THAN (speed)

    W/U

    Instruction that the specified position is to be crossed at or less than the specified speed.

    UM57

    CROSS (position) AT OR GREATER THAN (speed)

    W/U

    Instruction that the specified position is to be crossed at or greater than the specified speed.

    UM58

    CROSS (position) AT (time) AT (altitude)

    W/U

    Instruction that the specified position is to be crossed at the specified time and at the specified altitude.

    UM59

    CROSS (position) AT OR BEFORE (time) AT (altitude)

    W/U

    Instruction that the specified position is to be crossed before the specified time and at the specified altitude.

    UM60

    CROSS (position) AT OR AFTER (time) AT (altitude)

    W/U

    Instruction that the specified position is to be crossed after the specified time and at the specified altitude.

    UM61

    CROSS (position) AT AND MAINTAIN (altitude) AT (speed)

    NOTE 1. – A vertical range cannot be provided.

    NOTE 2. – This message element is equivalent to CSTU-14 plus LVLU-5 in Doc 4444.

    W/U

    Instruction that the specified position is to be crossed at the altitude specified, and at the specified speed.

    UM62

    AT (time) CROSS (position) AT AND MAINTAIN (altitude)

    W/U

    Instruction that the specified position is to be crossed at the specified time and at the specified altitude.

    UM63

    AT (time) CROSS (position) AT AND MAINTAIN (altitude) AT (speed)

    W/U

    Instruction that the specified position is to be crossed at the specified time at the specified altitude, and at the specified speed.

    TBL 14-3-9
    Speed Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM100

    AT (time) EXPECT (speed)

    R

    Notification that a speed instruction may be issued to take effect at the specified time.

    UM101

    AT (position) EXPECT (speed)

    R

    Notification that a speed instruction may be issued to take effect at the specified position.

    UM102

    AT (altitude) EXPECT (speed)

    R

    Notification that a speed instruction may be issued to take effect at the specified altitude.

    UM103

    AT (time) EXPECT (speed) TO (speed)

    R

    Notification that a speed range instruction may be issued to be effective at the specified time.

    UM104

    AT (position) EXPECT (speed) TO (speed)

    R

    Notification that a speed range instruction may be issued to be effective at the specified position.

    UM105

    AT (altitude) EXPECT (speed) TO (speed)

    R

    Notification that a speed range instruction may be issued to be effective at the specified altitude.

    UM106

    speed

    W/U

    Instruction to maintain the specified speed.

    UM107

    MAINTAIN PRESENT SPEED

    W/U

    Instruction to maintain the present speed.

    UM108

    speed

    W/U

    Instruction to maintain the specified speed or greater.

    UM109

    speed

    W/U

    Instruction to maintain the specified speed or less.

    UM110

    MAINTAIN (speed) TO (speed)

    W/U

    Instruction to maintain the specified speed range.

    UM111

    speed

    W/U

    Instruction that the present speed is to be increased to the specified speed and maintained until further advised.

    UM112

    speed

    W/U

    Instruction that the present speed is to be increased to the specified speed or greater, and maintained at or above the specified speed until further advised.

    UM113

    speed

    W/U

    Instruction that the present speed is to be reduced to the specified speed and maintained until further advised.

    UM114

    speed

    W/U

    Instruction that the present speed is to be reduced to the specified speed or less, and maintained at or below the specified speed until further advised.

    UM115

    speed

    W/U

    The specified speed is not to be exceeded.

    UM116

    RESUME NORMAL SPEED

    W/U

    Instruction to resume a normal speed. The aircraft no longer needs to comply with a previously issued speed restriction.

    UM134

    CONFIRM SPEED

    NOTE– NE response attribute.

    NE

    Request to report the speed defined by the speed type(s).

    UM136

    CONFIRM ASSIGNED SPEED

    NOTE– NE response attribute.

    NE

    Request to confirm the assigned speed.

    UM151

    speed

    NOTE– NE response attribute.

    NE

    Request for the earliest time or position when the specified speed can be accepted.

    TBL 14-3-10
    Speed Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM18

    speed

    Y

    Request for the specified speed.

    DM19

    REQUEST (speed) TO (speed)

    Y

    Request to fly within the specified speed range.

    DM34

    speed

    N

    Report indicating the speed defined by the specified speed types is the specified speed.

    DM39

    speed

    N

    Confirmation that the assigned speed is the specified speed.

    DM49

    speed

    Y

    Request for the earliest time or position that the specified speed can be expected.

    DM50

    WHEN CAN WE EXPECT (speed) TO (speed)

    Y

    Request for the earliest time at which a clearance to a speed within the specified range can be expected.

    DM67

    ‘WE CAN ACCEPT (speed) AT TIME (time)’

    N

    Indication that the specified speed can be accepted at the specified time.

    DM67

    ‘WE CANNOT ACCEPT (speed)’

    N

    Indication that the specified speed cannot be accepted.

    TBL 14-3-11
    Air Traffic Advisory Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM123

    beacon code

    W/U

    Instruction to select the specified SSR code.

    UM124

    STOP SQUAWK

    W/U

    Instruction to disable SSR transponder responses.

    UM125

    SQUAWK ALTITUDE

    W/U

    Instruction to include altitude information in the SSR transponder responses.

    UM126

    STOP ALTITUDE SQUAWK

    W/U

    Instruction to stop including altitude information in the SSR transponder responses.

    UM144

    CONFIRM SQUAWK

    NOTE– NE response attribute.

    NE

    Request to confirm the selected SSR code.

    UM153

    (altimeter)

    NOTE– The facility designation and the time of measurement cannot be provided.

    R

    Advisory providing the specified altimeter setting for the specified facility.

    UM154

    RADAR SERVICES TERMINATED

    R

    Advisory that the ATS surveillance service is terminated.

    UM155

    position

    NOTE– The provision of the position is required.

    R

    Advisory that ATS surveillance service has been established. A position may be specified position.

    UM156

    RADAR CONTACT LOST

    R

    Advisory that ATS surveillance contact has been lost.

    UM158

    ATIS code

    NOTE– The airport is not provided.

    R

    code

    UM163

    ICAO facility designation

    NE

    Notification to the pilot of an ATSU identifier.

    UM168

    DISREGARD

    N/E

    The indicated communication should be ignored.

    The previously sent uplink CPDLC message shall be ignored. DISREGARD should not refer to a clearance or instruction. If DISREGARD is used, another element shall be added to clarify which message is to be disregarded.

    UM179

    SQUAWK IDENT

    W/U

    Instruction that the ‘ident’ function on the SSR transponder is to be actuated.

    UM182

    CONFIRM ATIS CODE

    NE

    Instruction to report the identification code of the last ATIS received.

    TBL 14-3-12
    Air Traffic Advisory Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM47

    code

    N

    Report indicating that the aircraft is squawking the specified SSR code.

    DM79

    ATIS code

    N

    The code of the latest ATIS received is as specified.

    TBL 14-3-13
    Voice Communications Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM117

    CONTACT (ICAO unit name) (frequency)

    W/U

    Instruction to establish voice contact with the specified ATS unit on the specified frequency.

    UM118

    AT (position) CONTACT (ICAO unit name) (frequency)

    W/U

    Instruction at the specified position to establish voice contact with the specified ATS unit on the specified frequency.

    UM119

    AT (time) CONTACT (ICAO unit name) (frequency)

    W/U

    Instruction at the specified time to establish voice contact with the specified ATS unit on the specified frequency.

    UM120

    MONITOR (ICAO unit name) (frequency)

    W/U

    Instruction to monitor the specified ATS unit on the specified frequency. The flight crew is not required to establish voice contact on the frequency.

    UM121

    AT (position) MONITOR (ICAO unit name) (frequency)

    W/U

    Instruction at the specified position to monitor the specified ATS unit on the specified frequency. The flight crew is not required to establish voice contact on the frequency.

    UM122

    AT (time) MONITOR (ICAO unit name) (frequency)

    W/U

    Instruction at the specified time to monitor the specified ATS unit on the specified frequency. The flight crew is not required to establish voice contact on the frequency.

    UM157

    frequency

    NOTE– R response attribute.

    R

    Instruction to check the microphone due to detection of a continuous transmission on the specified frequency.

    TBL 14-3-14
    Voice Communications Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM20

    REQUEST VOICE CONTACT

    NOTE– Used when a frequency is not required.

    Y

    Request for voice contact on the specified frequency.

    DM21

    frequency

    NOTE– Used when a frequency is required.

    Y

    Request for voice contact on the specified frequency.

    TBL 14-3-15
    Emergency/Urgency Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM131

    REPORT REMAINING FUEL AND SOULS ON BOARD

    NOTE– NE response attribute.

    Y

    Request to provide the fuel remaining (time) and the number of persons on board.

    UM38

    UM39

    Used in combination with LVLU-6 and LVLU-9, which is implemented in FANS 1/A as:

    altitude

    altitude

    N

    Instruction to immediately comply with the associated instruction to avoid imminent situation.

    TBL 14-3-16
    Emergency/Urgency Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM55

    PAN PAN PAN

    NOTE– N response attribute.

    N

    Indication of an urgent situation.

    DM56

    MAYDAY MAYDAY MAYDAY

    NOTE– N response attribute.

    N

    Indication of an emergency situation.

    DM57

    (remaining fuel) OF FUEL REMAINING AND (remaining souls) SOULS ON BOARD

    NOTE– N response attribute.

    N

    Report indicating fuel remaining (time) and number of persons on board.

    DM58

    CANCEL EMERGENCY

    NOTE– N response attribute.

    N

    Indication that the emergency situation is canceled.

    TBL 14-3-17
    Standard Response Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM0

    UNABLE

    N

    Indication that the message cannot be complied with.

    UM1

    STANDBY

    N

    Indication that the message will be responded to shortly.

    UM2

    REQUEST DEFERRED

    NE

    Indication that a long‐term delay in response can be expected.

    UM3

    ROGER

    N

    Indication that the message is received.

    UM4

    AFFIRM

    NE

    Indication that ATC is responding positively to the message.

    UM5

    NEGATIVE

    NE

    Indication that ATC is responding negatively to the message.

    UM143

    CONFIRM REQUEST

    N

    Request to confirm the referenced request since the initial request was not understood. The request should be clarified and resubmitted.

    TBL 14-3-18
    Standard Response Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM0

    WILCO

    N

    Indication that the instruction is understood and will be complied with.

    DM1

    UNABLE

    N

    Indication that the instruction cannot be complied with.

    DM2

    STANDBY

    N

    Indication that the message will be responded to shortly.

    DM3

    ROGER

    NOTE– ROGER is the only correct response to an uplink free text message.

    N

    Indication that the message is received.

    DM4

    AFFIRM

    N

    Indication of a positive response to a message.

    DM5

    NEGATIVE

    N

    Indication of a negative response to a message.

    TBL 14-3-19
    Supplemental Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM164

    WHEN READY

    NE

    Indication that the associated instruction is to be executed when the flight crew is ready.

    UM165

    THEN

    NE

    Used to link two messages, indicating the proper order of execution of clearances/ instructions.

    UM166

    DUE TO TRAFFIC

    N

    Indication that the associated message is issued due to the specified reason.

    UM167

    DUE TO AIRSPACE RESTRICTION

    N

    Indication that the associated message is issued due to the specified reason.

    UM176

    MAINTAIN OWN SEPARATION AND VMC

    W/U

    Notification that the pilot is responsible for maintaining separation from other traffic and is also responsible for maintaining Visual Meteorological Conditions.

    TBL 14-3-20
    Supplemental Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM65

    DUE TO WEATHER

    N

    Indication that the associated message is issued due to specified reason.

    DM66

    DUE TO AIRCRAFT PERFORMANCE

    N

    Indication that the associated message is issued due to specified reason.

    TBL 14-3-21
    Free Text Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM169

    (free text)

    R

    A message or part of a message that does not conform to any standard message element in the PANSATM (Doc 4444).

    UM169

    (free text)

    R

    See Note

    UM169

    (free text)

    R

    See Note

    UM169

    (free text)

    R

    See Note

    UM169

    (free text)

    R

    See Note

    UM169

    (free text)

    R

    See Note

    UM169

    (free text)

    R

    See Note

    TBL 14-3-22
    Free Text Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM67

    free text

    NOTE– Medium (M) alert attribute.

    N

    DM68

    (free text)

    NOTE 1. – Urgency or Medium (M) alert attribute.

    NOTE 2. – Selecting any of the emergency message elements will result in this message element being enabled for the flight crew to include in the emergency message at their discretion.

    Y

    TBL 14-3-23
    System Management Uplink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM159

    (error information)

    N

    System‐generated notification of an error.

    UM160

    (ICAO facility designation)

    NOTE– The facility designation is required.

    N

    System‐generated notification of the next data authority or the cancellation thereof.

    UM161

    END SERVICE

    NE

    Notification to the avionics that the data link connection with the current data authority is being terminated.

    UM162

    SERVICE UNAVAILABLE

    NE

    Notification that the ground system does not support this message.

    TBL 14-3-24
    System Management Downlink Message Elements

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM62

    (error information)

    N

    System‐generated notification of an error.

    DM63

    NOT CURRENT DATA AUTHORITY

    N

    System‐generated rejection of any CPDLC message sent from a ground facility that is not the current data authority.

    DM64

    (ICAO facility designation)

    NOTE– Use by FANS 1/A aircraft in B1 environments.

    N

    System‐generated notification that the ground system is not designated as the next data authority (NDA), indicating the identity of the current data authority (CDA). Identity of the NDA, if any, is also reported.

    TBL 14-3-25
    Additional Uplink Messages

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    UM176

    MAINTAIN OWN SEPARATION AND VMC

    W/U

    Notification that the pilot is responsible for maintaining separation from other traffic and is also responsible for maintaining Visual Meteorological Conditions.

    TBL 14-3-26
    Additional Downlink Messages

    FANS 1/A Message Identifier

    Message Content

    Response

    Message element intended use

    DM74

    REQUEST TO MAINTAIN OWN SEPARATION AND VMC

    N

    States a desire by the pilot to provide his/her own separation and remain in VMC.

    DM78

    AT (time) (distance) (to/from) (position)

    N

    At the specified time, the aircraft's position was as specified.