AIM

8/15/19

5

−

3

−

6

En Route Procedures

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

Message Element

Intended Use

Format for 

Message Element

Display

UM49 CROSS (

posi-

tion

) AT AND MAIN-

TAIN (

altitude

)

Note 1. 

−

 A vertical

range cannot be pro-
vided.
Note 2. 

−

 This mes-

sage element is equiv-
alent to CSTU

−

1 plus

LVLU

−

5 in Doc 4444.

N/A

W/U

CSTU

−

1

Instruction that the
specified position
is to be crossed at
the specified level
or within the speci-
fied vertical range.

CROSS 

(position)

AT 

(level)

UM61 CROSS 

(posi-

tion) 

AT AND MAIN-

TAIN 

(altitude)

 AT

(speed)
Note 1. 

−

 A vertical

range cannot be pro-
vided.
Note 2. 

−

 This mes-

sage element is equiv-
alent 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.

CROSS 

(position)

AT 

(level)

 AT

(speed)

TBL 5

−

3

−

7

Air Traffic Advisory Uplink Message Elements

CPDLC Message Sets

Operational Definition in PANS

−

ATM (Doc 4444)

FANS 1/A

ATN B1

Response

Message 
Element 

Identifier

Message Element

Intended Use

Format for 

Message Element

Display

UM153 ALTIMETER

(altimeter)
Note  

−

 The facility

designation and the
time of measurement
cannot be provided.

UM213 

(facility

designation)

 

ALTIMETER 

(al-

timeter)
Note  

−

 The facility

designation is al-
ways provided and
the time of mea-
surement cannot be
provided.

ADVU

−

1

Advisory pro-
viding the
specified al-
timeter setting
for the speci-
fied facility.

(facility designa-
tion)

 ALTIMETER

(altimeter setting)

ADVU

−

1