S1P2 ROUTES SERVICE
END2END
DESCRIPTION
An overview of the FAA Implementation of Airborne Reroutes, Direct-To Fix,
Tailored Arrivals, and Controller Initiated Routes Services from a full end-toend perspective
August 29, 2014
Version 1.0
1
Written by the Data
Comm
Implementation
Team
Routes End to End Service Description
Contents
How to use this document ............................................................................................................................ 4
Scope of the Routes Service.......................................................................................................................... 4
Use cases we are mapping to ....................................................................................................................... 4
Operational assumptions .............................................................................................................................. 6
Operational Scenarios for Routes Service..................................................................................................... 6
Chapter 1: Initial En Route Services .............................................................................................................. 6
Initial Service: Operational Context for Crew Initiated Request for Direct To ......................................... 6
Initial Service: Operational Context for Controller Initiated Direct To ..................................................... 9
Initial Service: Operational Context for Ground System Initiated Reroute ............................................ 11
Chapter 2: Full En Route Services ............................................................................................................... 13
Full Service: Operational Context for Crew Initiated Request for Direct To ........................................... 13
Full Service: Operational Context for Controller Initiated Direct To ...................................................... 13
Full Service: Operational Context for Ground System Initiated Reroute................................................ 15
Full Service: Operational Context for Aircrew Initiated Re-route........................................................... 16
Messages Addressed in this End to End Document .................................................................................... 19
Definitions of terms .................................................................................................................................... 23
Equipage Assumptions ................................................................................................................................ 23
Considerations for loadable content .......................................................................................................... 24
General guidance for all uplinks ................................................................................................................. 24
Direct to clearances for duplicate waypoints ......................................................................................... 25
Guidance for constructing [routeclearances] ............................................................................................. 26
General [routeclearance] instructions .................................................................................................... 26
Airways in routeclearances ..................................................................................................................... 27
Message Specific Instructions ..................................................................................................................... 29
UM74 ...................................................................................................................................................... 29
UM77 ...................................................................................................................................................... 29
UM79 ...................................................................................................................................................... 29
UM80 ...................................................................................................................................................... 30
UM81 ...................................................................................................................................................... 30
2
UM83 ...................................................................................................................................................... 31
UM84 ...................................................................................................................................................... 32
UM169 .................................................................................................................................................... 32
Guidance for Multi-Element Messages....................................................................................................... 32
Appendix: Open Issues ................................................................................................................................ 34
Guidance for intercepting arrival and transition procedures midway ....................................................... 34
Descend Via................................................................................................................................................. 34
Appendix: Explanation of Route and Route Segment Clearances (UM79, UM80, and UM83) ................. 36
3
How to use this document
This document describes the routes service from the Data Comm Implementation Team’s (DCIT)
perspective. This document provides an overview of how the routes services will work based on the
FAA’s use cases. Additionally, this document includes rules for the ground automation to have the
greatest chance of building route uplinks that are loadable and operationally acceptable. These rules
can serve as the basis for requirements for ground systems.
This document is the parent to supporting documents that provide greater detail about how the routes
and reroutes services impact individual organizations. For example, supporting documentation like the
systems integration document and the local systems design and requirements will address detailed
interfaces. Use Cases provide greater detail about features in the controller’s CHI.
This document is considered complete for the FAA’s Final Investment Decision as all high risk items
pertaining to the routes service have been identified. However, open issues will continue to be
addressed by the DCIT, and this document will continually be updated as new problems and solutions
are identified.
In addition, this document contains information from ground system specifications, en route use cases
and leverages DCIT and industry user community input. This document represents the best available
information at the time it is published and will be updated as new information becomes available.
Scope of the Routes Service
This end to end service description covers both the S1P2 initial and full versions of the CPDLC Routes,
Airborne Reroute (ABRR), and Initial Tailored Arrivals (ITAs) services. The complete lists of uplink and
downlink messages included in the routes services appear in Table 7 - Table 10.
Because the en route services will be implemented in phases, this end to end document is divided into
two chapters
1. Initial en route services (controller initiated reroutes, direct-to fix, Airborne Reroutes, pilot
altitude and direct-to fix requests)
2. Full en route services (Tailored Arrivals, Pilot initiated routes)
Use cases we are mapping to




NUT CPDLC Routes Use Case 07_30_14
DRAFT FULL CPDLC Routes Use Case 3_5_14
NUT CPDLC Airborne Reroute (ABRR) Use Case 07_30_14
DRAFT FULL CPDLC Initial Tailored Arrivals Use Case 3_5_14
4
5
Operational assumptions
It is assumed that the routes service will operate domestically, ground automation will build the
clearance for the controller, all datalink equipped aircraft are eligible for the procedures, and the
aircrew will be properly trained to participate.
According to the GOLD section 4.1.2.3, the controller should use voice to communicate with an aircraft
that is below 10,000 ft AGL to minimize distractions and pilot head down time.
For the ground automation to build messages that load, it is assumed that the aircraft’s current route is
what the ground automation knows.
Operational Scenarios for Routes Service
1. Crew initiated request direct to (initial service)
2. Controller initiated direct to (initial service)
3. Ground initiated route, including (initial service)
a. Traffic Flow Management (TFM) initiated reroutes (initial service)
b. controller initiated re-routes (initial service)
4. Aircrew initiated route request (includes AOC initiated to crew via ACARS, weather deviations)
(full service)
5. Enhanced ground initiated routes (full service)
a. ITAs (full service)
b. weather deviations (full service)
c. holding (full service)
Chapter 1: Initial En Route Services
The initial routes service will support the crew initiated request for direct to, controller initiated direct
to, and some scenarios of ground initiated routes (TFM initiated and controller initiated). ITAs and
aircrew initiated route requests will be implemented in Full Services which are discussed in Chapter 2.
The messages supported in Initial route services are limited to those in Table 7 and Table 9.
Initial Service: Operational Context for Crew Initiated Request for Direct To
The messages for a crew or Pilot Initiated Downlink (PID) for direct-to-fix are shown in Figure 1. The
steps of this scenario are covered in the CPDLC Routes Use Case, and they are summarized in Table 1.
6
1. Request direct
to [position]
7. WILCO/
UNABLE
5. Proceed direct
to [position]
3. Standby
Figure 1. Crew initiated request for direct to or request for reroute
Table 1. Operational steps for crew initiated request for direct to routing (Initial Service)
Step
Operating Method
1
The flight crew sends a CPDLC downlink message, for example DM22
REQUEST DIRECT TO [pos].
2
Upon ATSU system receipt of DM22, the controller is notified.
3
The controller may respond with a UM1 STANDBY.
4
Upon aircraft system receipt of the STANDBY, the flight crew is notified.
5
If the controller can accommodate the crew’s request, the controller responds to
the downlink with UM74 PROCEED DIRECT TO [pos]. The ground system
will concatenate UM169 REST OF ROUTE UNCHANGED to any route uplink,
except when the clearance includes the destination.
If the controller cannot accommodate the crew’s request, the controller responds
to the downlink with UM0 UNABLE.
6
Upon aircraft system receipt of the response message, the flight crew is notified.
If the controller sent UM74, the crew views the message and loads it into the
FMC (if applicable).
7W
If the crew can comply with the direct to, the crew responds with DM0 WILCO.
7
Step
Operating Method
7U
If the crew cannot comply with the direct to, the crew responds with DM1
UNABLE.
8
Initial Service: Operational Context for Controller Initiated Direct To
The controller can initiate a direct to clearance through a keyboard command. The steps of this scenario
are described in the CPDLC Routes Use Case, and they are summarized in Table 2 . Figure 2 shows the
uplinks and downlinks between the aircraft and ground.
3. Standby
5. WILCO/
UNABLE
1. Proceed direct to
[position]
Figure 2. Controller initiated direct to
9
Table 2. Operational steps for controller initiated direct to routing (Initial Service)
Step
Operating Method
1
The controller sends a CPDLC message for direct routing to a fix that is on the
aircraft’s currently cleared route. UM74 PROCEED DIRECT TO [pos] is
concatenated with UM169 REST OF ROUTE UNCHANGED, unless the
[position] is the destination airport.
When the ATSU system sends a CPDLC message, the controller is notified.
2
Upon aircraft system receipt of a CPDLC message requiring a response, the
flight crew is notified. The flight crew reviews the uplink, and if the message is
loadable, the flight crew loads the clearance in the FMC.
3
The flight crew may respond with DM2, STANDBY.
4
Upon ATSU system receipt of DM2 STANDBY, the controller is not notified
but the STANBY response can be viewed.
5W
After the flight crew has determined that they can comply with the direct to, the
flight crew responds with a DM0 WILCO.
5U
If the aircrew cannot comply with the direct to, the flight crew responds with a
DM1 UNABLE. The crew may append DM65 DUE TO WEATHER or DM66
DUE TO AIRCRAFT PERFORMANCE.
6
Upon ATSU system receipt of the flight crew response:
 when the response is WILCO the uplink in progress indication is removed, or
 when the response is an UNABLE or NEGATIVE, the controller is notified.
10
Initial Service: Operational Context for Ground System Initiated Reroute
According to the CPDLC Routes Use Case, a ground system initiated reroute could occur for several
reasons, including a Traffic Flow Management (TFM) generated reroute or a controller initiated re-route.
The following operational method in Table 3 is intentionally written to be generic and capture both
types of ground system initiated reroutes. In this example, there are several options for the type of
route uplink that could be sent including um79, um80, and um83. Figure 3 shows the messaging for a
ground system initiated reroute.
3. Standby
5. WILCO/
UNABLE
1. [routeclearance]
message
Figure 3. Messaging for ground system initiated reroute
11
Table 3. Operational steps for ground initiated reroute (Initial Service)
Step
Operating Method
1
The controller sends a CPDLC message for reroute, UM79 CLEARED TO
[pos] VIA [routeclearance] + UM169 REST OF ROUTE UNCHANGED.
(Alternatively, the ground could build a reroute message with UM80
CLEARED [routeclearance], or UM83 AT [position] CLEARED
[routeclearance].)
Note that for TFM initiated reroutes, UM169 [TRAFFIC FLOW
MANAGEMENT REROUTE] will also be appended to the uplink.
2
Upon aircraft system receipt of the uplink, the flight crew is notified. The flight
crew reviews the uplink and loads the clearance in the FMC.
3
The flight crew may respond with DM2, STANDBY.
4
Upon ATSU system receipt of DM2 STANDBY, the controller is not notified
but the STANBY response can be viewed.
5W
After the flight crew has determined that they can comply with the new route,
the flight crew responds with a DM0 WILCO.
5U
If the uplink is unacceptable (a partial load occurs or an irresolvable
discontinuity results), the flight crew responds with a DM1 UNABLE. The
crew may append DM65 DUE TO WEATHER or DM66 DUE TO AIRCRAFT
PERFORMANCE if those reasons apply.
6
Upon ATSU system receipt of the flight crew response:
 when the response is WILCO the uplink in progress indication is removed,
or
 when the response is an UNABLE or NEGATIVE, the controller is notified.
12
Chapter 2: Full En Route Services
In addition to the capabilities implemented during initial en route services, full en route services will
introduce ITAs and aircrew initiated route requests. The uplink and downlink messages that will be
added during the Full En Route Service and are listed in
13
Table 8 shows all the uplink and downlink messages that will be added when the Full Routes Service is
implemented. All the initial services messages from Table 7 will remain available.
Table 8 and Table 10.
Full Service: Operational Context for Crew Initiated Request for Direct To
For full services, an aircrew initiated request for direct to would be sent the same way as during initial
services, and the ground’s response would always be either UM74 or UNABLE. Reference chapter 1,
Figure 1 and Table 1 for a description of the operating method and messaging.
Full Service: Operational Context for Controller Initiated Direct To
For full services, a controller initiated direct routing would be sent the same way as during initial
services, but the controller could send three additional messages, UM75, UM77 and UM78. See Figure
4 for messaging.
3. Standby
5. WILCO/
UNABLE
1. Direct to
message
Figure 4. Messaging for controller initiated direct to (full services)
14
Table 4. Operational steps for controller initiated direct to routing (Full Services)
Step
Operating Method
1
The controller sends a CPDLC message for direct routing to a fix that is on the
aircraft’s currently cleared route with UM74 PROCEED DIRECT TO [pos],
UM75 WHEN ABLE PROCEED DIRECT TO [position], UM77 AT [pos]
PROCEED DIRECT TO [pos], or UM78 AT [altitude] PROCEED DIRECT TO
[position], (whichever message is appropriate for the situation) concatenated
with UM169 REST OF ROUTE UNCHANGED, unless the position is the
destination airport.
When the ATSU system sends a CPDLC message, the controller is notified.
2
Upon aircraft system receipt of a CPDLC message requiring a response, the
flight crew is notified. The flight crew reviews the uplink, and if the message is
loadable, the flight crew loads the clearance in the FMC.
3
The flight crew may respond with DM2, STANDBY.
4
Upon ATSU system receipt of DM2 STANDBY, the controller is not notified
but the STANBY response can be viewed.
5W
After the flight crew has determined that they can comply with the direct to, the
flight crew responds with a DM0 WILCO.
5U
If the aircrew cannot comply with the direct to, the flight crew responds with a
DM1 UNABLE. The crew may append DM65 DUE TO WEATHER or DM66
DUE TO AIRCRAFT PERFORMANCE.
6
Upon ATSU system receipt of the flight crew response:
 when the response is WILCO the uplink in progress indication is removed, or
 when the response is an UNABLE or NEGATIVE, the controller is notified.
15
Full Service: Operational Context for Ground System Initiated Reroute
In Full Services, a ground system initiated reroute could occur for several reasons, including a Traffic
Flow Management (TFM) generated reroute, a controller initiated re-route, or ITAs. In addition to
UM79, UM80, and UM83, the controller could also send UM81 and UM84 in full services. The following
operational method in Table 5 is intentionally written to be generic and capture all types of ground
system initiated reroutes.
Figure 5 shows the messaging for a ground system initiated reroute.
3. Standby
5. WILCO/
UNABLE
1. [routeclearance]
message
Figure 5. Messaging for ground system initiated reroute
16
Table 5. Operational steps for ground initiated reroute
Step
Operating Method
1
The controller sends a CPDLC message for reroute, UM79 CLEARED TO
[pos] VIA [routeclearance] + UM169 REST OF ROUTE UNCHANGED.
(Alternatively, the ground could build a reroute message with UM80
CLEARED [routeclearance], UM81 CLEARED [procedurename], UM83 AT
[position] CLEARED [routeclearance], or UM84 AT [position] CLEARED
[procedurename].)
Note that for TFM initiated reroutes, UM169 [TRAFFIC FLOW
MANAGEMENT REROUTE] will also be appended to the uplink.
2
Upon aircraft system receipt of the uplink, the flight crew is notified. The flight
crew reviews the uplink and loads the clearance in the FMC.
3
The flight crew may respond with DM2, STANDBY.
4
Upon ATSU system receipt of DM2 STANDBY, the controller is not notified
but the STANBY response can be viewed.
5W
After the flight crew has determined that they can comply with the new route,
the flight crew activates the route in the FMC and responds with a DM0
WILCO.
5U
If the uplink is unacceptable (a partial load occurs or an irresolvable
discontinuity results), the flight crew responds with a DM1 UNABLE. The
crew may append DM65 DUE TO WEATHER or DM66 DUE TO AIRCRAFT
PERFORMANCE if those reasons apply.
6
Upon ATSU system receipt of the flight crew response:
 when the response is WILCO the uplink in progress indication is removed,
or
 when the response is an UNABLE or NEGATIVE, the controller is notified.
Full Service: Operational Context for Aircrew Initiated Re-route
Figure 6 shows the messaging involved with a crew initiated reroute.
17
1. Request
[routeclearance]
7. WILCO/
UNABLE
[routeclearance]
message
3. Standby
Figure 6. Messaging for aircrew initiated request for reroute
The GOLD outlines the Dynamic Airborne Reroute Procedure (DARP) for an airborne aircraft to
request reroute clearances that are initiated by an Aeronautical Operational Control (AOC). The
following steps are in line with the GOLD for DARP.
If the re-route is initiated from the AOC, the following steps will occur prior to Table 6:
a. The flight crew will receive a re-route suggestion from their AOC via an ACARS uplink.
b. The crew loads this route into the inactive route, reviews the re-route, and modifies it if
needed.
c. When applicable, the crew deletes any waypoints on the proposed route that have already
been sequenced.
d. If the re-route is acceptable to the crew, they follow the steps in Table 6 to request a route
revision from ATC.
18
Table 6. Operational steps for aircrew/AOC initiated re-route
Step
Operating Method
1
At least 10 minutes prior to the divergence waypoint, the flight crew sends a
CPDLC downlink message, for example DM24 REQUEST [routeclearance]
where the first fix in the [routeclearance] is the next waypoint ahead of the
aircraft.
2
Upon ATSU system receipt of DM24, the controller is notified.
3
The controller may respond with a UM1 STANDBY.
4
Upon aircraft system receipt of the STANDBY, the flight crew is notified.
5
If the controller can accommodate the crew’s request, the controller responds to
the downlink with either UM80, UM79, UM83, UM81, or UM84. When the
clearance excludes the destination, the ground system will concatenate UM169
REST OF ROUTE UNCHANGED to route uplinks.
If the controller cannot accommodate the crew’s request completely, the
controller responds to the downlink with UM0 UNABLE.
If the controller can only accommodate some portion of the request, the
controller responds to the downlink with UM0 UNABLE, and they may use
freetext to indicate they are working on another route revision.
When the requested clearance is rejected by the controller, the flight crew
should continue in accordance with the existing clearance.
6
Upon aircraft system receipt of the response message, the flight crew is notified.
If the controller sent an FMC loadable message, the crew views the message and
loads it into the FMC. If the message is not FMC loadable, the aircrew views
the message and manually enters the route modifications.
7W
If the crew can comply with the new route, the crew responds with DM0
WILCO.
7U
If the crew cannot comply with the new route, the crew responds with DM1
UNABLE. The crew may append DM65 DUE TO WEATHER or DM66 DUE
TO AIRCRAFT PERFORMANCE.
8
Upon ATSU system receipt of the flight crew response:
 when the response is WILCO the uplink in progress indication is removed, or
 when the response is an UNABLE or NEGATIVE, the controller is notified.
19
Messages Addressed in this End to End Document
The SSSD contains the master list of all messages for each service, and the following message tables are
a subset of the SSSD. These tables need to be kept consistent with the SSSD, as the SSSD is maintained
outside DCIT.
Table 7 shows all the uplink and downlink messages planned for the Initial Routes Service. These
messages will remain available when full services are implemented later.
Table 7. Messages for Initial Routes service
FANS
MSG ID
UM74
UM79
UM80
UM83
UM137
DM22
DM40
FANS Message Element
PROCEED DIRECT TO [position]
CLEARED TO [position] VIA [routeclearance]
CLEARED [routeclearance]
AT [position] CLEARED [routeclearance]
CONFIRM ASSIGNED ROUTE
REQUEST DIRECT TO [position]
ASSIGNED ROUTE [routeclearance]
20
Dialog
Type
Route
Route
Route
Route
Route
Route
Route
ENR S1P2 Segment
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
Table 8 shows all the uplink and downlink messages that will be added when the Full Routes Service is
implemented. All the initial services messages from Table 7 will remain available.
Table 8. Messages added for the Full Routes Service
FANS
MSG ID
UM75
UM77
UM78
UM81
UM82
UM84
UM91
UM92
UM93
DM15
DM23
DM24
DM27
DM41
DM51
FANS Message Element
WHEN ABLE PROCEED DIRECT TO [position]
AT [position] PROCEED DIRECT TO [position]
AT [altitude] PROCEED DIRECT TO [position]
CLEARED [procedurename]
CLEARED TO DEVIATE UP TO [distanceoffset] [direction]
OF ROUTE
AT [position] CLEARED [procedurename]
HOLD AT [position] MAINTAIN [altitude] INBOUND
TRACK [degrees] [direction] TURNS [leg type]
HOLD AT [position] AS PUBLISHED MAINTAIN [altitude]
EXPECT FURTHER CLEARANCE AT [time]
REQUEST OFFSET [distanceoffset] [direction] OF
ROUTE
REQUEST [procedurename]
REQUEST [routeclearance]
REQUEST WEATHER DEVIATION UP TO
[distanceoffset] [direction] OF ROUTE
BACK ON ROUTE
WHEN CAN WE EXPECT BACK ON ROUTE
21
Dialog
Type
ENR
S1P2
Segment
Route
Route
Route
Route
S1P2-F
S1P2-F
S1P2-F
S1P2-F
Route
Route
S1P2-F
S1P2-F
Route
Route
Route
S1P2-F
S1P2-F
S1P2-F
Route
Route
Route
S1P2-F
S1P2-F
S1P2-F
Route
Route
Route
S1P2-F
S1P2-F
S1P2-F
The messages in Table 9 include uplinks and downlinks for the Initial Altitude and Speed services. In
addition, messages that do not belong to one specific service category are listed, such as freetext and
Wilco. The altitude and speed messages are included in this end to end document to reduce the need
for more end to end documents later.
Table 9. Messages for Initial Altitude, Speed, and other services
FANS
MSG ID
FANS Message Element
Dialog
Type
ENR S1P2
Segment
UM0
UM1
UNABLE
STANDBY
N/A
N/A
S1P2-I, S1P2-F
S1P2-I, S1P2-F
UM19
UM20
UM23
MAINTAIN [altitude]
CLIMB TO AND MAINTAIN [altitude]
DESCEND TO AND MAINTAIN [altitude]
Altitude
Altitude
Altitude
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
UM36
UM37
EXPEDITE CLIMB TO [altitude]
EXPEDITE DESCENT TO [altitude]
Altitude
Altitude
S1P2-I, S1P2-F
S1P2-I, S1P2-F
UM38
UM39
UM49
Altitude
Altitude
Altitude
Altitude &
Speed
N/A
N/A
N/A
N/A
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
UM61
UM159
UM166
UM167
UM169
IMMEDIATELY CLIMB TO [altitude]
IMMEDIATELY DESCEND TO [altitude]
CROSS [position] AT AND MAINTAIN [altitude]
CROSS [position] AT AND MAINTAIN [altitude] AT
[speed]
ERROR [errorinformation]
DUE TO TRAFFIC
DUE TO AIRSPACE RESTRICTION
[freetext]
UM169
UM169
UM169
UM177
DM0
DM1
[freetext] "DUE TO WEATHER"
[freetext] "REST OF ROUTE UNCHANGED"
[freetext] "TRAFFIC FLOW MANAGEMENT REROUTE"
AT PILOTS DISCRETION
WILCO
UNABLE
N/A
N/A
N/A
N/A
N/A
N/A
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
DM2
DM3
DM6
DM9
DM10
DM20
STANDBY
ROGER
REQUEST [altitude]
REQUEST CLIMB TO [altitude]
REQUEST DESCENT TO [altitude]
REQUEST VOICE CONTACT
N/A
N/A
Altitude
Altitude
Altitude
N/A
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
DM38
DM62
DM65
DM66
DM73
ASSIGNED ALTITUDE [altitude]
ERROR [errorinformation]
DUE TO WEATHER
DUE TO AIRCRAFT PERFORMANCE
[versionnumber]
Altitude
N/A
N/A
N/A
N/A
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
22
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
S1P2-I, S1P2-F
The messages in Table 10 include uplinks and downlinks for the Full Altitude and Speed services, as well
as messages that are not specific to one service category.
Table 10. Messages for Full Altitude, Speed, and other services
FANS
MSG ID
UM4
UM5
UM30
UM31
UM32
UM46
UM47
UM48
UM55
UM56
UM57
UM106
UM107
UM108
UM109
UM116
UM131
UM136
UM169
UM171
UM173
DM7
DM18
DM25
DM28
DM29
DM30
DM32
DM34
DM37
DM39
DM49
DM75
DM76
FANS Message Element
AFFIRM
NEGATIVE
MAINTAIN BLOCK [altitude] TO [altitude]
CLIMB TO AND MAINTAIN BLOCK [altitude] TO [altitude]
DESCEND TO AND MAINTAIN BLOCK [altitude] TO
[altitude]
CROSS [position] AT [altitude]
CROSS [position] AT OR ABOVE [altitude]
CROSS [position] AT OR BELOW [altitude]
CROSS [position] AT [speed]
CROSS [position] AT OR LESS THAN [speed]
CROSS [position] AT OR GREATER THAN [speed]
MAINTAIN [speed]
MAINTAIN PRESENT SPEED
MAINTAIN [speed] OR GREATER
MAINTAIN [speed] OR LESS
RESUME NORMAL SPEED
REPORT REMAINING FUEL AND SOULS ON BOARD
CONFIRM ASSIGNED SPEED
[freetext] "DUE TO SPACING"
CLIMB AT [verticalrate] MINIMUM
DESCEND AT [verticalrate] MINIMUM
REQUEST BLOCK [altitude] TO [altitude]
REQUEST [speed]
REQUEST CLEARANCE
LEAVING [altitude]
CLIMBING TO [altitude]
DESCENDING TO [altitude]
PRESENT ALTITUDE [altitude]
PRESENT SPEED [speed]
LEVEL [altitude]
ASSIGNED SPEED [speed]
WHEN CAN WE EXPECT [speed]
AT PILOTS DISCRETION
REACHING BLOCK [altitude] TO [altitude]
23
Dialog
Type
ENR
S1P2
Segment
N/A
N/A
Altitude
Altitude
S1P2-F
S1P2-F
S1P2-F
S1P2-F
Altitude
Altitude
Altitude
Altitude
Speeds
Speeds
Speeds
Speeds
Speeds
Speeds
Speeds
Speeds
N/A
Speeds
N/A
Altitude
Altitude
Altitude
Speeds
N/A
Altitude
Altitude
Altitude
Altitude
Speeds
Altitude
Speeds
Speeds
N/A
Altitude
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
S1P2-F
Definitions of terms
FMC Loadable
A loadable message can be automatically entered into the FMC when the crew selects the LOAD
prompt. For example, when routeclearances are loaded into the FMC, and the new route is
automatically populated rather than manually entered by the crew.
Non-loadable
A non-loadable message cannot be auto-loaded into the FMS and the LOAD prompt is not displayed.
Some messages are non-loadable by design. For example, freetext is not loadable. Whether a specific
message is loadable or non-loadable depends on the aircraft type.
Partial load
After the crew selects the LOAD prompt, the FMC may display a message, “Partial Clearance Loaded” to
indicate that one or more parameters in the uplink did not load. For example, the route may be missing
an airway or procedure. Because the crew cannot resolve the ground’s intention, crews must reject
messages that result in partial clearance loaded. Crews should use CPDLC or voice to resolve the
clearance with the ground.
Discontinuity
A discontinuity in the route can occur after loading a routeclearance. Discontinuities indicate that there
is a gap in the route, i.e. no defined path between two waypoints. Crews should reject any clearance
that results in a discontinuity that they are unable to resolve.
Equipage Assumptions
The rules for ground automation in this end to end document are written with the assumption that the 922 FMC is operating on MD-11 aircraft, and the U11 FMC is operating on the B737.
For example, on the 737, the U11 FMC software must be used for uplinks with arrival,
departure, approach, and transition procedures, and uplinks that attach altitude and/or speed
constraints to a latitude/longitude point as part of the [routeclearance] variable. The FMC
version U10.8a, as well as all preceding versions, will not load these items in a routeclearance,
resulting in “partial load” annunciations that cannot be resolved by the aircrew.
24
And on the MD-11 -921 FMC, messages using the [routeclearance] parameter must adhere to
the following rule when using airways with Transitions or Arrivals: The end of the airway cannot
be the first fix in the Transition or the Arrival. The consequence of using the same point for the
end of the airway and the first point in the Transition or Arrival is a discontinuity which requires
crew intervention to resolve. This issue has been resolved on the -922 FMC.
The DCIT’s strategy is to write rules for uplinks in order to accommodate the lowest common
denominator in terms of aircraft type specific limitations. The ground system is not expected to build
messages specific to aircraft type.
Considerations for loadable content
In general, the ground should uplink as much loadable content as possible. The intention is to leverage
the capability of auto-loading routes which will reduce workload for crews, one of the most powerful
features of datalink. If a loadable message exists that meets the intention of the clearance, the ground
automation should select that loadable message first, rather than a non-loadable message. Finally, the
ground system should construct messages so the least amount of repeat material is uplinked to the
cockpit (except as noted below). Reducing the amount of clearance material that the crew and
controller must review will improve response times and reduce errors.
Additionally, the ground should not exclude messages that are not loadable from being sent. Messages
that are not loadable are still valuable because they reduce radio transmissions, increase clarity, and
increase the overall capability of the routes service.
General guidance for all uplinks
The ground system should follow all ASN1 data definition rules for route construction from DO-258A. As
a result, radials cannot be uplinked as they are not defined in the ASN1.
When using the [position] parameter, the ground should follow data definition rules from DO-258A for
fixnames, navaids, airports, latitudeLongitudes, and placebearingdistance. This rule will resolve issues
such as fake/ghost intersections, VORs coded as airports, XXX (incomplete route indicator), and some
problems with duplicate waypoints.
For example, when sending uplinks with [position], the ground should code the position
appropriately as a fixname, navaid, airport, lat/long, or place bearing distance.
The following is an example of an ERAM Automatic Departure Route (ADR) that assigns a
ghost/fake intersection (i.e. SNADP). The fix SNADP is not published, but it is adapted in the
ZHU ERAM. If an aircraft files ‘KMSY DCT CEW....’, ERAM will insert the adapted ADR route
string ‘..SNADP..’ The resulting route will be ‘KMSY..SNADP..CEW.....’ However, since the fix
‘SNADP’ is not published and not stored in a navigation database, the route will not be loadable
on the aircraft.
25
When using the [procedure] parameter, the ground should follow data definition rules from DO-258A.
When using the [position] parameter with fixnames, navaids, and airports, the ground should only
uplink fixnames, navaids, and airports that are published in the current ground navigation database.
This rule will resolve fake/ghost intersections.
When using the [procedure] parameter, the ground should only uplink [procedurenames] that are
published in the current navigation database.
Direct to clearances for duplicate waypoints
Duplicate waypoints will not be supported for uplink purposes. Voice will be used when a route
amendment contains a clearance to or from a duplicate waypoint.
For example, for the route KLAX..FMN..LBL..CAP..LBL..VHP..KCLE, voice will be used for
clearances such as, “Proceed direct to LBL” or “At FMN proceed direct LBL.”
26
Guidance for constructing [routeclearances]
As a reminder, the ground should choose the message that uplinks the least amount of repeat material
to the cockpit. The ground should also choose the uplink that will minimize/eliminate the number of
partial loads or load failures for various fleet types, and many of the rules in this end to end document
are written to achieve that goal.
General [routeclearance] instructions

The ground will include the optional lat/long field for Published identifiers (waypoint names) in the
route information variable of [routeclearance] uplinks.

If the [routeclearance] in an uplink contains an arrival procedure/transition, then the last waypoint
in the [routeinformation] must be the same as the first fix in the transition (if specified) or the
procedure (if a transition is not specified). If the uplink contains a Transition, the Transition name
must be included in the [proceduretransition] field of the [procedurename] variable. If the
[routeclearance] in an uplink contains a departure procedure/transition, then the first waypoint in
the [routeinformation] must be the same as the last fix in the transition (if specified) or the
procedure (if a transition is not specified).
o
For example, the following uplink abides by this rule, as KEACH is the first point of the
KEACH1 arrival procedure, so it must be listed last in [routeinformation]:
UM80 : Cleared [routeclr]
dest airport(): KLAX
arr procname(): ARR,KEACH1
route info(): 4
(pub): MANEY
(pub): DUETS
(pub): DINTY
(pub): KEACH
o
No transition specified
For example, the following uplink abides by this rule, as CEBAD is the first point of the
CEBAD transition, so it must be listed last in [routeinformation]. Additionally, the CEBAD
transition is included in the [proceduretransition] field:
UM80 : Cleared [routeclr]
dest airport(): KLAX
arr procname(): ARR,KEACH1,CEBAD
route info(): 4
(pub): MANEY
(pub): DUETS
(pub): DINTY
(pub): CEBAD
27
CEBAD transition specified

When the controller’s intent is to send only the arrival procedure (no transition), the ground should
exclude the [proceduretransition] from the uplink.

When an uplink includes the [proceduretransition] variable in a [routeclearance], the ground must
use published, named transitions and arrival procedures. For example, the ground cannot uplink
PIECH.TUDOR2, where PIECH is coded as the [proceduretransition], because PIECH is not a published
arrival transition. Instead, the ground should use the published transition names for the TUDOR2:
LMT, LKV, or RBL in the [proceduretransition] variable.

For messages using the [routeclearance] parameter, a common waypoint must exist between the
flight segments listed here to avoid discontinuities in the uplink:
a. A departure procedure/transition and the en route segment
b. The en route segment and the arrival/transition
c. The arrival and the approach/transition
d. The en route segment and the approach/transition
e. A departure procedure/transition and the arrival/transition or
approach/transition (if there is no en route segment).
Airways in routeclearances
For the clearance to load properly, the ground system must use published named waypoints to
designate airway entry, termination and intersection points.
Note: This rule is an update to the previous guidance given for [airwayidentifier] in DO-258A,
Table 4.6-33 [routeclearance] Variables.
As a consequence of this rule, the first element in the route cannot be an airway. Instead, a
published identifier specifying the airway entry point must be the first element of the route.
For example, the following uplink is properly constructed for a route with multiple
airways.
The ground’s route is: KEWR./.GYNTS..SUZIE.J80..J100.BCE..OAL.MOD4..KSFO
(80) : Cleared [routeclr]
orig airport(): KEWR
dest airport(): KSFO
arr procname(): ARR,MOD4,OAL
route info(): 7
(pub): GYNTS
SUZIE is the entry to J80
(pub): SUZIE
(airway): J80
SAKES is the intersection of J80 and J100
(pub): SAKES
(airway): J100
BCE is the exit from J100
(pub): BCE
(pub): OAL
28
If there is not a published waypoint at an airway intersection, the ground must specify the exit
point for the first airway by using a published, named waypoint as the exit point. Then, the
ground could insert a latlong at the mathematical intersection of the two airways. After the
latlong, the ground must use a published named waypoint for the second airway’s entry point.
The following UM80 illustrates this scenario:
The ground’s route is: KEWR./.COPES.J75..J61.FORTS..KRDU
The uplink built would be
(80) : Cleared [routeclr]
orig airport(): KEWR
dest airport(): KRDU
route info(): 7
(pub): COPES
(airway): J75
MURPH is inserted, is the exit from J75
(pub): MURPH
(l/l): N39 09.0 W076 53.0
Lat/long is inserted, the mathematical intersection
(pub): OTT
OTT is inserted, is the entry to J61
(airway): J61
(pub): FORTS
If no [publishedidentifier] exists between the aircraft’s current position and the intersecting
airway, the ground cannot send this type of clearance.
29
Message Specific Instructions
UM74
UM74 PROCEED DIRECT TO [position] will insert a direct leg from the aircraft’s present position to the
specified fix.


The specified position will be on the aircraft’s current route per the Routes Use Case. Allowed
waypoint types are: navaid, fixname, airport, latitudelongitude, and placebearingdistance.
Uplinking “PROCEED DIRECT TO [destinationairport]” will result in clearing all route points and
arrival/approach procedures in the aircraft’s route.
UM77
UM77 AT [pos] PROCEED DIRECT TO [pos] will insert a leg from the first specified fix to the second
specified fix.


The positions must be specified the same way as they are in the current route. For example, if
the [position] is coded as a navaid in the aircraft’s route, it must be coded as a navaid in the
uplink.
For both the first [position] and the second [position], the ground will always use a point on the
cleared route. Allowed waypoint types are: navaid, fixname, airport, latitudelongitude, and
placebearingdistance.
UM79
UM79 CLEARED TO [position] VIA [route clearance] will replace everything in the route before the
“TO” position with the [routeclearance] contents.


The specified “TO” position in UM79 must be a point in the aircraft’s current flight plan.
The ground will concatenate UM79 with the freetext message, “Rest of route unchanged.”

The specified “TO” position must be a point after the SID or the SID Transition (if these are present)
up to but excluding the first point in the Arrival, Approach, or associated Transition in the aircraft’s
active route.
For UM79, when the “TO” point is not an airway termination, the ground system will not include
the “TO” point as the last element in the routeinformation field.For UM79, when the “TO” point is
an airway termination point, the ground system will include the “TO” point as the last element in
the routeinformation field after the airway.

o This example message illustrates this rule:
(79) : Cleared To [pos] Via [routeclr]
pos(nav): BOS
route info(): 4
(pub): BREZY
30
(pub): PACER
(airway): J42
(pub): BOS


BOS is repeated in routeinfo
The ground system will not include the arrival airport as the [position] in UM79.
o (Reference GOLD 6.1.3.9) When using UM 79 CLEARED TO [position] VIA [route clearance],
ATC should not populate the [position] field with the destination airport unless the route is
specified to destination. All forecast weather data for the uplinked waypoints is lost from
the FMS when the new route is activated.
Guidance about when to use UM79:
o When the ground wants to replace the route from the aircraft’s present position leading up
to a point. UM79 only replaces a segment of the route.
UM80
UM80 CLEARED [routeclearance] will replace everything in the route with the routeclearance
contents.

UM80 should always be defined from next fix from aircraft’s current position to the destination.
Therefore, the ground should never concatenate the freetext message, “REST OF ROUTE
UNCHANGED” with UM80.
o
o


Reference GOLD 6.1.3.8: ATC should only use UM 80 CLEARED [route clearance] to issue
CPDLC re-route clearances if the route is specified from the aircraft present position to
destination. All forecast weather data is lost from the FMS when the new route is activated.
Note: For military aircraft, the clearance limit may mean destination airport.
UM80 should be used when the ground needs to send arrival procedures, when UM83 is not
available for use.
Guidance about when to use UM80:
o When the ground wants to replace the entire route, start to finish. This message is ideal for
non-airborne re-routes or predeparture clearances when the ground needs to change the
aircraft’s route in its entirety.
o In general, the ground should avoid using UM80 if only a segment is to be changed.
However, there may be cases where UM80 is the only message that will work.
UM81
UM81 CLEARED [procedurename] inserts or replaces the existing terminal area procedure of the
specified type in the active route.

UM81 will only be used to send arrivals and arrival transitions. The ground will not send approaches
or SIDS with UM81.
31


When the procedure is an arrival or transition, the procedure name must match that of a procedure
at the airplane’s destination airport and the [procedurename] must correspond to a procedure in
the navigation database on the airplane.
UM81 will be used to change an arrival procedure where the new arrival procedure’s transition fix is
already the last fix of the aircraft’s current cleared route.
UM83
UM83 AT [pos] CLEARED [routeclearance] will replace everything in the route after the specified AT
position with the [routeclearance] contents.
Note: UM83 with arrival procedures causes issues on some aircraft. To accommodate that
limitation, the FAA has implemented a switch to enable/disable uplink of UM83. When UM83 is
available for use, the following rules apply.


For UM83, the AT position must be a position in the aircraft’s current route.
For UM83, the ground should always give the final point as the destination. Therefore, the ground
should never concatenate the freetext message, “REST OF ROUTE UNCHANGED” with UM83.
o
Reference GOLD 6.1.3.7, ATC should only use UM 83 AT [position] CLEARED [route
clearance] to issue CPDLC re-route clearances if the following conditions are satisfied:
 a) The route is specified to destination; and
 b) The [position] in UM 83 is on the currently cleared route.
 Note.—All forecast weather data after [position] is lost from the FMS when the new
route is activated.

UM83 will be used when the revision includes a route change starting at a specified position (the
“AT” point) which is the last point in the SID or the SID Transition (if these are present) or any point
after that, excluding any point within the Arrival, Approach, or associated Transitions.

For UM83, when the “AT” point is an airway entry point, the ground system will include the “AT”
point as the first element in the [routeinformation] field and the airway itself as the second element.
o The following example illustrates this rule:
(83) : At [pos] Cleared [routeclearance]
pos(nav): LNK
dest airport(): KSFO
arr procname(): ARR,MOD4,OAL
route info(): 7
(pub): LNK
LNK is repeated in routeinfo
(airway): J146
(pub): GLD
(airway): J80
(pub): MLF
(airway): J58
(pub): OAL
32


For UM83, when the “AT” point is not an airway entry point, the ground system will not include the
“AT” point as the first element in the [routeinformation] field.
Guidance about when to use UM83
o When the ground wants to replace the route after a specified point up to the destination.
UM83 only replaces a segment of the route.
UM84
UM84 AT [pos] CLEARED [procedurename] will insert or replace an existing procedure of the type
specified. However, the DCIT recommends using it to give an aircraft a descent clearance on an
already assigned procedure, as UM80 is preferred for changes to arrival procedures since it is
loadable on more aircraft.



The [position] needs to be in the aircraft’s cleared route.
The [position] needs to be at the start of the arrival procedure or the arrival transition. Example: At
[CEBAD] cleared [KEACH1.CEBAD]
UM84 will only be used to send arrivals and arrival transitions that are already present in the
aircraft’s cleared route. New procedures/changed procedures will not be sent with UM84; instead
UM80 should be used because it is loadable on all aircraft types.
Approaches will not be sent with UM84.

Per DO-258-A, the [procedure] variable has a maximum size of 6 characters.

Per DO-258-A, the [proceduretransition] variable has a maximum size of 5 characters.

o
When the procedure is an arrival, then that arrival procedure must be compatible with the
assigned runway.
UM169
UM169[freetext] elements will include no more than 80 characters.
Guidance for Multi-Element Messages
When an ATC clearance containing one or more loadable message element is loaded into the route, all
loadable elements will load sequentially. Non-loadable elements in the same uplink will be displayed,
but will not be loaded and will not affect processing of the loadable elements in any way. Because
loadable elements load sequentially, the order of the elements is important. For example, an element
like UM50 (CROSS [position] between [level] and [level]) depends on the existence of the specified
[position] in the route. If the same uplink also contains UM80, which replace the entire route and delete
any previous changes, then UM80 should appear first and UM50 should follow.
33


A clearance that replaces the entire route (UM80) needs to be the first loadable element in an
uplink.
As general guidance, use of [routeclearance] elements helps to reduce the potential for
unintended loads that can result from concatenating multiple loadable message elements. The
ground should use messages with the [routeclearance] variable rather than piecing together
multiple elements.
o Example: CROSS ABC AT FL190 +PROCEED DIRECT TO XYZ. The last element may clear
ABC and its crossing constraint. A better solution would be to use a [routeclearance],
like uM79. Ex: CLEARED to XYZ via [ABC/FL190, XYZ].
34
Appendix: Open Issues
For all route uplinks, the first element needs to be a point that is some distance ahead of current aircraft
position (X minutes or X miles). (The intent is to not send a route point that has already been over
flown.) The DCIT needs time to figure out the requirement for the ground to use. This is an open item.
For a ground initiated re-route, the second rule that needs to be determined is how much time or
distance ahead the first divergence point must be. The DCIT needs time to figure out the requirement
for the ground to use. This is an open item.
Guidance for intercepting arrival and transition procedures midway
Aircraft operators and controllers have a need to intercept procedures mid-way through. For situations
where an arrival or transition procedure is to be intercepted part way down, the ground will not uplink
anything. Voice will be used instead, until the flight deck group develops their preference.
Descend Via
35
Nat Tracks
If an operator wants to file a nat track, the nat track must be broken into a series of lat/longs because
the FMC cannot load a Nat track. This issue will exist for Flex tracks as well.
Possible solution for Nat Tracks & Flex Tracks.
ATOP defines the tracks as a series of lat/longs and uplinks this way. ERAM could receive the
definitions for the Nat tracks via interface to ATOP and expand the Nat tracks, uplinking this
way, with limitation that the route expansion will end at the entry and the fixname to the nat
track. Expansion by ERAM will extend through the end fix of the track definition.
The ground will include UM169 including the NAT definition.
36
Appendix: Explanation of Route and Route Segment Clearances (UM79, UM80, and UM83)
(This section is an excerpt from Gordon Sandell’s Loading of ATC Clearances into the FMS.)
There are 3 clearance elements that replace all or large segments of the existing route that may be
loaded directly into the FMS on the various Boeing airplanes. They are as follows:
79
80
83
CLEARED TO position VIA route clearance
CLEARED routeclearance
AT position CLEARED route clearance
All four of these message elements are implemented on all Boeing FANS-1 airplane models (737, 747400, 747-8, 757/ 767, 777, 787, and MD-11).
The way in which each of these clearances modifies the route in the FMC is a little different. Message
element um80 will replace the route in its entirety, as shown in Figure 7 and Figure 8 below.
CLEARED XXXXX – YYYYY – ZZZZZ
Replaces flight plan between origin and destination (on ground), or
Between airplane and destination (in air)
EFGHI
JKLMN
OPQRS
Inserts the fixes/ATS routes in the [routeinformation]
ZABCD
UVWXY
ZZZZZ
YYYYY
PQRST
XXXXX
KLMNO
FGHIJ
ABCDE
ORIG
Figure 7. Loading of UM80 when aircraft is airborne
Loading of um80 when the airplane is on the ground is shown in Figure 8 below.
37
DEST
PREDEPARTURE CLEARANCE XXXXX – YYYYY – ZZZZZ
Replaces flight plan between origin and destination
Inserts the fixes/ATS routes in the [routeinformation]
EFGHI
JKLMN
ZABCD
UVWXY
OPQRS
DEST
ZZZZZ
YYYYY
PQRST
KLMNO
FGHIJ
ABCDE
XXXXX
ORIG
Figure 8. Loading of um80 when aircraft is on ground
The other route clearance uplinks (um79 and um83) will each only replace a segment of the route.
Message element 79 (CLEARED TO position VIA routeclearance) will replace the flight plan between
where the airplane is and the specified waypoint, as shown in Figure 9 below.
38
CLEARED TO JKLMN VIA XXXXX – YYYYY – ZZZZZ
Replaces flight plan between airplane and JKLMN
Inserts the fixes/ATS routes in the [routeinformation]
ZABCD
UVWXY
EFGHI
JKLMN
OPQRS
DEST
ZZZZZ
YYYYY
PQRST
XXXXX
KLMNO
FGHIJ
ABCDE
ORIG
Figure 9. Loading of um79
Note that Figure 9 shows what happens when the specified [position] is a fix in the existing active route.
If it is not a fix in the existing active route, then the position and the contents of the [routeinformation]
parameter will be inserted, followed by a flight plan discontinuity and the remainder of the existing enroute segment of the route. For the example shown, if the waypoint JKLMN did NOT exist in the active
route, then the result of this uplink would be:
XXXXX
YYYYY
ZZZZZ
JKLMN
-- DISCONTINUITY -PQRST
UVWXY
ZABCD
EFGHI
OPQRS
39
Message element 83 (AT position CLEARED routeclearance) will replace the flight plan, beginning at the
specified position, and continuing right up to the destination, as shown in Figure 10 below.
AT UVWXY CLEARED XXXXX – YYYYY – ZZZZZ
Replaces flight plan between UVWXY and destination
Inserts the fixes/ATS routes in the [routeinformation]
EFGHI
JKLMN
OPQRS
DEST
ZZZZZ
ZABCD
YYYYY
UVWXY
XXXXX
PQRST
KLMNO
FGHIJ
ABCDE
ORIG
Figure 10. Loading of um83
Again, Figure 10 shows what happens when the specified [position] is a fix in the existing active route. If
it is not a fix in the existing active route, then the position and the contents of the [routeinformation]
parameter will be inserted after the remainder of the existing en-route segment of the route, separated
from it by a flight plan discontinuity. For the example shown, if the waypoint UVWXY did NOT exist in
the active route, then the result of this uplink would be:
PQRST
ZABCD
EFGHI
JKLMN
OPQRS
-- DISCONTINUITY -UVWXY
40
XXXXX
YYYYY
ZZZZZ
41