TBL 5-3-8

Voice Communications Uplink Message Elements (COMU)
CPDLC Message Sets

Operational Definition in PANS-ATM (Doc 4444)

ATN B1

Response

Message
Element
Identifier

UM117 CONTACT
(ICAO unit name)
(frequency)

UM117 CONTACT (unit name)
(frequency)

W/U

COMU-1

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

UM120 MONITOR
(ICAO unit name)
(frequency)

UM120 MONITOR (unit name)
(frequency)

W/U

COMU-5

Instruction to mon- MONITOR
itor the specified
(unit name)
ATS unit on the
(frequency)
specified frequency. The flight crew
is not required to
establish voice
contact on the frequency.

FANS 1/A

Message Element
Intended Use

Format for
Message Element
Display
CONTACT
(unit name)
(frequency)

TBL 5-3-9

Voice Communications Downlink Message Elements (COMD)
CPDLC Message Sets
FANS 1/A
DM20 REQUEST
VOICE CONTACT
Note - Used when a
frequency is not required.

Operational Definition in PANS-ATM (Doc 4444)

ATN B1

Response

Message
Element
Identifier

COMD-1

Message Element
Intended Use
Request for voice
contact on the specified frequency.

Format for
Message Element
Display
REQUEST
VOICE
CONTACT
(frequency)

TBL 5-3-10

Emergency/Urgency Uplink Message Elements (EMGU)
CPDLC Message Sets
FANS 1/A
Used in combination with
LVLU-6 and LVLU-9,
which is implemented in
FANS 1/A as:

Operational Definition in PANS-ATM (Doc 4444)

ATN B1

Response

Message
Element
Identifier

EMGU-2

Message Element
Intended Use
Instruction to immediately comply
with the associated
instruction to avoid
imminent situation.

Format for
Message Element Display
Immediately

UM38 IMMEDIATELY
CLIMB TO (altitude)
UM39 IMMEDIATELY
DESCEND TO (altitude)

En Route Procedures

5-3-7