End-end DCL Trials Procedures
1. The aircraft operator will provide a list of participating tail numbers. The list will be
maintained within DTAP, and will updated with additions and deletions.
2. At the appropriate time, the airline files the Flight Plan (FP) for a participating flight via
normal flight plan filing mechanisms. The flight plan must have the Flight Identification
(FID) in field 7, the departure airport, and registration number in field 18, per standard
requirements for FANS operations.
When a NAT Track is filed in the flight plan, the airline shall file the flight plan using the
lat/long waypoint definitions for the track, rather than the NAT Track name or the NAT
Track grid point names. When a NAT track is filed in the flight plan in this manner, the
airline shall include “these coordinates are identified as the [NAT Track name]” in the
airlines remarks section for aircrew (this item is not part of the Flight Plan filed with the
FAA).
If an airline files “FRC” in the Remarks field of the Flight Plan, PDC clearances will be
inhibited for the flight, while DCL processing will continue.
When an airway is included in the flight plan, the entry and exit point should be
designated by a published named waypoint. If there is an airway crossing point between
two airways, i.e. where two airways cross.
Note: If the filed FP does not designate any applicable airways entry, exit, and crossing
points between two airways by a published named waypoint, the uplinked DCL will not
load on some aircraft. This will result in a rejection of the uplink by the aircrew, and
reversion to voice.
3. For participating flights at an airport utilizing “auto mode”, the airline shall:
a. Automatically identify PDCs received from the Tower, and prevent these from
being transmitted to the aircraft.
b. Automatically identify PDC requests received from the aircraft, and respond
saying “request Departure Clearance using FANS-1/A or request your ATC
clearance via voice”.
4. Approximately 30 minutes prior to the proposed departure time (specifically at a
parameter time configured to the site’s current strip printing time), ERAM/Host triggers
strip printing with the planned route. the DTAP shall compare the route as filed by the
airline with the route as modified by HCS/ERAM:
a. If routes are identical, DTAP shall create a DCL for controller review.
i. if the filed FPL did not include a SID/transition, the DLC shall include a
um169 with the phrase “CLEARED AS FILED”
ii. if the filed FPL did include a SID/transition, the um169 shall include the
SID/transition name and the phrase “THEN AS FILED”
iii. DTAP shall not include a um80 in DCLs with a um169 with the phrase
“AS FILED”.
b. If routes are not identical, DTAP shall create a DCL that includes a um80 with
the cleared route of flight.
c. The controller reviews the clearance and sends it to automation; automation
formats it into a FANS-1/A clearance using UM 80, UM169 UM19, UM169,
UM123 and, and places the clearance in a queue awaiting downlink request (see
Appendix for sample messages).
Note: See step 9 for the DCL creation rules observed by DTAP.
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5. For each flight plan, the DTAP shall compare the registration number in field 18 with the
list of participating aircraft list from Step 1.
a. When there is no registration number, or the registration number is not part of the
participating flight list, the PDC clearance will be handled as it is today, and no
DCL clearance will be sent.
b. When the registration number is part of the daily participating flight list the
controller:
i. Removes the PDC from the system.
ii. Edits the DCL Departure clearance, and adds it to the Departure
clearance queue (available for transmission to the flight crew upon DCL
request).
6. At the appropriate time, and while still at the gate, the aircrew logs-on to FANS using the
local DTAP Tower address.
7. The DTAP will accept valid log-ons, correlate accepted log-ons with proposed FPs for
which DCLs have been approved, and establish CPDLC connections with aircraft.
FP/Log-on correlation occurs on three triggering events (Log-on acceptance, DCL
approval, and update to flight data used for correlation), as described below.
a. When a log-on request message (FN_CON) has valid and required data, the
DTAP will accept the log-on and send a positive log-on response (FN_AK). In all
other cases the DTAP will send a negative response (FN_AK).
b. If the log-on is attempted and no response is received, or a negative response is
received, the aircrew may attempt one further log-on before reverting to voice for
their departure clearance.
c. When a log-on is accepted, the log-on will be stored.
d. When a DCL clearance is created (approved) for a proposed FP, FP to log-on
correlation will be attempted using the set of log-ons that have been positively
responded to.
e. When correlation is not successful, accepted log-ons and FPs with DCLs are
retained (stored) for future correlation attempts.
Note: Tthe specific period of retention for log-ons and FPs will be established by
a variable parameter, whose specific value is not yet determined (starting values
may be on the order of 3-6 hours). This may be an area for trials may be a good
forum for providing first information in this area.
f. When correlation is successful, the ATC ground system shall attempt to establish
a CPDLC connection with the aircraft by sending a CR1 (to which the aircraft
responds with a CC1.
g. Only one log-on from a given aircraft registration will be stored for correlation at
any given time. If a new log-on request for the same aircraft registration is
received and accepted, it will replace the stored log-on data for that aircraft
registration. If the new log-on has a different FID than the previously stored logon data, any existing FP correlation or CPDLC connection will be terminated.
8. At the impropriate time, and after establishment of CPDLC connection, the aircrew
requests the Departure Clearance using only DM25 (REQUEST CLEARANCE).
Note: If the aircrew uses any other message type to request the Departure Clearance, to
include appending a freetext to the DM25, the DTAP shall respond with a freetext
“MESSAGE NOT SUPPORTED BY THIS ATS UNIT”.
9. The DTAP
a. Delivers the Departure clearance to the aircraft using FANS-1/A message
elements um80, um169, um19, um169 and um123 all within the same message
(see Appendix A for message samples). The clearance will contain an
intermediate level to maintain, a beacon code, and the cleared route of flight, and
potentially the STAR at the arrival airport (not Approach or Arrival Runway). No
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b.
c.
d.
e.
f.
g.
altitude or speed constraints shall be included in the loadable part of the
message (um80), other than those automatically loaded from the aircraft’s Nav
Database with an uplinked STAR.
The uplink does not contain a departure runway or SID in the loadable portion
(um80), though it may contain a SID and transition as appropriate in a nonloadable um169 freetext element within the clearance.
Note: The SID is included in the non-loadable portion because FAA systems
cannot include the departure runway in the uplink and this is required for correct
loading of the SID. Although departure runway cannot be provided within the
DCL Trials, inclusion of departure runway is an important feature for aircrew and
the FAA is investigating how to provide it in the operational DCL system.
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.
Based on the flight plan from the airline, the DTAP will uplink the unpublished
lat/long waypoint definitions for the track, rather than the NAT Track name or the
NAT Track grid point names. DTAP will not uplink a message with more than 20
unpublished lat/long waypoints.
The DTAP will determine which waypoint names have two or more locations in
the worldwide published Nav database.
i. When the DTAP determines that a waypoint name has two or more
locations, and can unambiguously identify the waypoint name intended
for the departure clearance, the DTAP shall include the optional lat/long
field for that waypoint name in the Departure Clearance uplink.
ii. When the DTAP determines that a waypoint name has two or more
locations, and cannot unambiguously identify the waypoint name
intended for the departure clearance, the DTAP will not include the
optional lat/long field for that waypoint name in the Departure Clearance
uplink.
Note: Some aircraft require inclusion of the optional lat/long field to process
duplicate waypoint names. In case ‘ii’, above, the uplink will be unloadable for
these aircraft; aircrew will need to reject the clearance and revert to voice.
Um169[freetext] elements shall include no more than 80 characters.
When an airway is included in the uplink, the entry and exit point should be
designated by a named waypoint
Note: If the filed flight plan does not designate any applicable airways entry, exit,
and crossing points between two airways by a published named waypoint, the
uplinked DCL will not load on some aircraft. This will result in a rejection of the
uplink by the aircrew, and reversion to voice.
10. If the airline has requested a DCL copy, the DTAP shall provide a decoded copy of the
clearance, excepting beacon code, to the Airline Host via the airline-supplied 7-character
ACARS address. The DCL copy shall include a header “COURTESY COPY – NOT AN
ATC CLEARANCE. Requesting airlines shall be capable of distinguishing the DCL copy
from a PDC clearance. Upon receipt of the DCL copy the Airline Host shall send an
acknowledgement back to the DTAP system. The Airline Host may optionally provide the
flight’s Gate along with the acknowledgement of the DCL copy. The Airline Host shall
ensure that the DCL copy is not forwarded to the aircrew/aircraft.
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11. The aircrew loads the DCL clearance into the FMS and reviews it. If acceptable, the flight
crew activates the route in the FMS and downlinks “WILCO”. If unacceptable, or if a
“Partial Load” or “Load Failure” indication occurs, the crew downlinks “UNABLE”. If a
DISCON is present when the clearance is loaded, and the aircrew cannot resolve the
DISCON, the crew downlinks “UNABLE”.
12. In accordance with the operating airline’s procedures, the aircrew requests wind/temp
data, Take-Off data, and Performance Data. These requests shall not be done using the
route request function.
Note: Using the route request function risks overwriting the clearance received from ATC.
Therefore, other request functions shall be used for this data.
13. One or more Revised Departure clearances may be sent by ATC prior to aircraft
departure (see Appendix A for sample messages). These clearances will contain some or
all of the same information as the initial Departure clearance, The uplink will never
contain a departure runway or SID in the loadable portion (um79, um80, or um83),
though it may contain a SID and transition as appropriate in a non-loadable um169
freetext element. No altitude or speed constraints shall be included in the loadable part of
the message (um79, um80, um83), other than those automatically loaded from the
aircraft’s Nav Database with an uplinked STAR. Revisions may contain um80, um83, or
um79, according to the information being revised.
a. Formatting rules and notes listed for the original DCL clearance also apply to
DCL revisions.
b. Um83 shall 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.
c. The DTAP shall not include a departure airport in um83.
d. The Um79 shall be used when the revision includes a route change ending at the
specified position (the “TO” point) is a point after the SID or the SID Transition (if
these are present) up to and including the last en-route point prior to the first
point in the first Arrival, Approach, or associated Transition in the aircraft’s active
route.
e. When a um79 is used, the uplink shall include a um169 freetext stating that the
rest of the route is unchanged following the “TO” point in the uplink (e.g. “AFTER
MCB REST OF ROUTE UNCHANGED” for a um79 with a “TO” point of “MCB”).
f. The DTAP shall not include an arrival airport in um79.
g. Um80 shall be used when the revision includes a route change and um79 or
um83 is not appropriate according to rules 13.b. and 13.c, above.
Note 1: Although departure runway cannot be provided within the DCL Trials, inclusion of
departure runway is an important feature for aircrew and the FAA is investigating how to
prove it in the operational DCL system.
14. If the airline has requested a DCL Revision copy, the DTAP shall provide a decoded copy
of the clearance, excepting beacon code, to the Airline Host via the airline-supplied 7character ACARS address. The DCL Revision copy shall include a header “COURTESY
COPY – NOT AN ATC CLEARANCE. Requesting airlines shall be capable of
distinguishing the DCL copy from a PDC clearance. Upon receipt of the DCL Revision
Copy, the Airline Host shall send an acknowledgement back to the DTAP system. The
Airline Host may optionally provide the flight’s Gate along with the acknowledgement of
the DCL Revision copy. The Airline Host shall ensure that the DCL Revision copy is not
forwarded to the aircrew/aircraft.
15. The aircrew loads the DCL clearance into the FMS and reviews it. If acceptable, the flight
crew activates the route in the FMS and downlinks “WILCO”. If unacceptable, or if a
“Partial Load” or “Load Failure” indication occurs, the crew downlinks “UNABLE”. If a
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DISCON is present when the clearance is loaded, and the aircrew cannot resolve the
DISCON, the crew downlinks “UNABLE”.
16. The DTAP shall disconnect CPDLC with the aircraft at a time parameter after departure.
The disconnect time will be an adjustable parameter, initially set to coincide with the
average aircraft passing through 12,000ft on climbout.
Note: Aircrew transiting to another FANS-supporting airspace (e.g. Oakland Oceanic,
New York Oceanic) will need to log-on to the next FANS facility. No automatic transfer of
the CPDLC connection will occur.
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Appendix A: Sample Messages
Initial DCL – Base Line Clearance w/RNAV SID
UM
Number
UM80
{RouteClearance}
UM169
[freetext]
UM19
MAINTAIN
[level]
UM169
[freetext]
UM123
SQUAWK [code]
Notes:.
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Response
Attributes
Urg(N)/Alr(A)/
Resp(W/U)/Rec(RC)
ASN1
Definition
Airport Departure[0]
Airport Destination [1]
Procedure Arrival [6]
Route information [7]
Urg(N)/Alr(L)
FreeText ::=
/Resp(R)
IA5String (SIZE
(1..256))
Urg(N)/Alr(A)/
LevelType ::=
Resp(W/U)/Rec(VC) CHOICE
levelFeet [0]
levelFlightLevel[2]
Urg(N)/Alr(L)/
FreeText ::=
Resp(R)
IA5String (SIZE
(1..256))
Urg(N)/Alr(M)/
Resp(W/U)
Code ::= SEQUENCE
SIZE (4) OF
CodeOctalDigit
CodeOctalDigit ::=
INTEGER (0..7)
Sample Clearance
KDFW
KMIA
SSCOT1.SZW
EIC..AEX.J50.CEW.J2.SZW
CLARE2.EIC RNAV SID
Lab Validation
(6) Optional if a ARR is not
part of the route Information
MAINTAIN 10000FT
EXP FLXXX WI 10 MIN
AFT DEP. DEP FREQ 118.55
EDCT 2145Z
SQUAWK 0562
FL/FT, MIN/MILES, Freq is
Ctrl selected from DP,
EDCT – display if HADS
provides
1. Repeating the last fix in the DP as part of the first fix in the Route Information sequence (e.g. Clare2.EIC with EIC starting the
route information)
2. For arrivals the Arrival Transition fix will be included as the last fix in the Route information sequence as appropriate to the
route of flight.
3. Second UM169 (additional Info) is a structured free text message with variable fields – FLXXX, MINS/MILES, DP Freq,
EDCT if provided
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Initial DCL – SID with Unique Textual DP
UM
Number
UM80
{RouteClearance}
Response
Attributes
Urg(N)/Alr(A)/
Resp(W/U)/Rec(RC)
ASN1
Definition
Airport Departure[0]
Airport Destination [1]
Procedure Arrival [6]
Route information [7]
UM169
[freetext]
UM19
MAINTAIN
[level]
Urg(N)/Alr(L)
/Resp(R)
Urg(N)/Alr(A)/
Resp(W/U)/Rec(VC)
UM169
[freetext]
Urg(N)/Alr(L)/
Resp(R)
FreeText ::= IA5String
(SIZE (1..256))
LevelType ::=
CHOICE
levelFeet [0]
levelFlightLevel[2]
FreeText ::= IA5String
(SIZE (1..256))
UM123
SQUAWK [code]
Urg(N)/Alr(M)/
Resp(W/U)
8
Code ::= SEQUENCE
SIZE (4) OF
CodeOctalDigit
CodeOctalDigit ::=
INTEGER (0..7)
Sample Clearance
Lab Validation
KLGA
KDFW
LIT.BYP5
LANNA.J48.MOL.J22.VXV..SYI
..MEM.J66.LIT
LGA2.LGA SID
RWY 13 WHITESTONE CLIMB
MAINTAIN 5000FT
EXP FLXXX WI 10 MIN
AFT DEP. DEP FREQ 120.4
EDCT 2145Z
SQUAWK 3021
FL/FT, MIN/MILES,
Freq is Ctrl selected
from DP, EDCT –
display if HADS
provides
Complex Revision
Case 1:
Route Modification:
 No change to the DP or Transition is allowed. Route information: Route change from point on original route to destination to
include arrival procedure as applicable.
UM
Response
ASN1
Sample Clearance
Lab Validation
Number
Attributes
Definition
UM169
Urg(N)/Alr(L)
FreeText ::= IA5String REVISED ROUTE
[freetext]
/Resp(R)
(SIZE (1..256))
UM83
AT [position]
CLEARED
[routeClearance]
UM19
MAINTAIN
[level]
Urg(N)/Alr(M)/
Resp(W/U)
PositionPosition ::=
SEQUENCE SIZE (2)
OF Position – atposition
RouteClearance ::=
SEQUENCE
Airport Destination [1]
Procedure Arrival [6]
Route information [7]
Urg(N)/Alr(A)/
LevelType ::= CHOICE
Resp(W/U)/Rec(VC) levelFeet [0]
levelFlightLevel[2]
CEW
KMIA
SSCOT1.SZW
KRSTO..SZW
MAINTAIN 10000FT
Notes:
Within um83 the specified position (the “AT” point) must be 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.
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Case 2:
Procedure Departure and different transition fix. Route information: different transition fix, links with an existing downstream route of
flight waypoint
UM
Response
ASN1
Sample Clearance
Lab Validation
Number
Attributes
Definition
UM169
Urg(N)/Alr(L)
FreeText ::=
REVISED DP TRSN AND RTE
[freetext]
/Resp(R)
IA5String (SIZE
(1..256))
UM79
CLEARED TO
[position] VIA
[routeClearance]
UM169
[freetext]
UM19
MAINTAIN
[level]
Urg(N)/Alr(M)/
Resp(W/U)
PositionPosition ::=
SEQUENCE SIZE (2)
OF Position – toposition
RouteClearance ::=
SEQUENCE
Airport Departure[0]
Route information [7]
Urg(N)/Alr(L)
FreeText ::= IA5String
/Resp(R)
(SIZE (1..256))
Urg(N)/Alr(A)/
LevelType ::=
Resp(W/U)/Rec(VC) CHOICE
levelFeet [0]
levelFlightLevel[2]
CLEARED TO MCB
KDFW
SWB
CLARE2.SWB
MAINTAIN 10000FT
Notes:
1. Within um79 the specified position (the “TO” point) must be a point after the SID or the SID Transition (if these are present)
up to and including the first point in the first Arrival, Approach, or associated Transition in the aircraft’s active route.
2. Route amendment from aircraft ground position to an existing FMS route waypoint – MCB/AEX - Inserts modification to
existing route (e.g. Baseline DCL Clearance UM80)
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Case 3
Complete change of route using UM80 - Procedure Departure and different transition fix, Route information: different
transition fix, change of route to connect to a new arrival procedure to original destination
UM
Response
ASN1
Sample Clearance
Lab Validation
Number
Attributes
Definition
UM169
Urg(N)/Alr(L)
FreeText ::= IA5String REVISED DP AND RTE
[freetext]
/Resp(R)
(SIZE (1..256))
UM80
Urg(N)/Alr(A)/
Airport Departure[0]
KDFW
{RouteClearance} Resp(W/U)/Rec(RC) Airport Destination [1] KMIA
Procedure Arrival [6]
CYY.CYY6
Route information [7]
CLL.IAH.J86.LEV.Q102.CYY
UM169
Urg(N)/Alr(L)
FreeText ::= IA5String ARDIA3.CLL RNAV SID
[freetext]
/Resp(R)
(SIZE (1..256))
UM19
Urg(N)/Alr(A)/
LevelType ::=
MAINTAIN 10000FT
MAINTAIN
Resp(W/U)/Rec(VC) CHOICE
[level]
levelFeet [0]
levelFlightLevel[2]
UM169
Urg(N)/Alr(L)/
FreeText ::= IA5String REVISED DEP FREQ 125.12
[freetext]
Resp(R)
(SIZE (1..256))
Notes:
1. Amendment to the baseline DCL Clearance to replace the existing route of flight with a New Route of flight with New Arrival
Procedure – using UM80
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