TBL 5-3-6

Crossing Constraint Message Elements (CSTU)
CPDLC Message Sets

Operational Definition in PANS-ATM (Doc 4444)

FANS 1/A

ATN B1

Response

Message
Element
Identifier

UM49 CROSS (position) AT AND MAINTAIN (altitude)
Note 1. - A vertical
range cannot be provided.
Note 2. - This message element is equivalent to CSTU-1 plus
LVLU-5 in Doc 4444.

W/U

CSTU-1

Instruction that the CROSS (position)
specified position
AT (level)
is to be crossed at
the specified level
or within the specified vertical range.

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.

UM61 CROSS
(position) AT AND
MAINTAIN (level)
AT (speed)

W/U

CSTU-14

Instruction that the
specified position
is to be crossed at
the level or within
the vertical range,
as specified, and at
the specified
speed.

Message Element
Intended Use

Format for
Message Element
Display

CROSS (position)
AT (level) AT
(speed)

TBL 5-3-7

Air Traffic Advisory Uplink Message Elements
Operational Definition in PANS-ATM (Doc 4444)

CPDLC Message Sets
FANS 1/A

ATN B1

Response

UM153 ALTIMETER
(altimeter)
Note - The facility
designation and the
time of measurement
cannot be provided.

UM213 (facility
designation)
ALTIMETER (altimeter)
Note - The facility
designation is always provided and
the time of measurement cannot be
provided.

ADVU-1

5-3-6

Message
Element
Identifier
Advisory providing the
specified altimeter setting
for the specified facility.

Message Element
Intended Use

Format for
Message Element
Display

(facility designaADVU-1
tion) ALTIMETER
(altimeter setting)

En Route Procedures