End-end DCL Trials Procedures
1. 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 (reg: GOLD 2.2.6,2.a).
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 has the option to 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).
For flights that will participate in the DCL trials, airlines shall include “FRC DCL” in the the
first 22 characters of the Remarks field of the Flight Plan (e.g. RMK/FRC DCL). Other
RMK entries can and should still be included in the flight plan as necessary. If an airline
files “FRC DCL” 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 shall be designated
by a published named waypoint.
Note 1: If the filed FP does not designate any applicable airways entry and exit,
points with 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. Airway intersection points do not need to have the intersection point
designated.
2. 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”.
3. 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. 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 8 for the DCL creation rules observed by DTAP.
1
4. DTAP shall search for the presence of “FRC DCL” and in the Remarks field of flight plans
and presents flight plans with this value to the controller. . When the flight plan contains
FRC DCL in the flight plan the controller:
a. Removes the PDC from the system.
b. Edits the DCL Departure clearance, and adds it to the Departure clearance
queue (available for transmission to the flight crew upon DCL request).
Note: When there is no FRC DCL in the Remarks field of the flight plan, the PDC
clearance will be handled as it is today, and no DCL clearance will be sent.
5. At the appropriate time, and while still at the gate, the aircrew logs-on to FANS using the
local DTAP Tower address. This can be done anytime after the airline has filed the Flight
Plan with the FAA.
6. The DTAP will accept valid log-ons, provided that log-on can be correlated with an FP
containing the same registration number and Flight Identification, and the FP contains
“FRC DCL” in the Remarks field. , Once it has accepted the log-on, DTAP will attempt to
establish a CPDLC connection with aircraft. Specifically:
a. When a log-on request message (FN_CON) has valid and required data, and
that log-on data is correlated with a flight plan, 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 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).
d. When an update (change) to flight data items used for correlation are received
for a FP that is correlated with a log-on, the CPDLC connection associated with
that flight plan will first be terminated, and the crew will then need to reaccomplish the log-on..
Note: For the trials, flight data items used for correlation are the aircraft registration
and the Flight ID. For the operational system, the lat/long position reported in the logon may also be used.
7. At the appropriate 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 UM169 freetext
“MESSAGE NOT SUPPORTED BY THIS ATS UNIT”.
8. The DTAP
a. If the DM25 request is sent prior to the appropriate time for the airport involved
(e.g. P-30), the DTAP will send a “STANDBY” message. At the appropriate time
for the airport, the DTAP will then conduct ‘b’ (see next).
b. Upon receipt of the aircrew request (if received at the appropriate time for the
airport, or at the appropriate time for the airport (if a “STANDBY” has been sent
for an early request, DTAP delivers the Departure clearance to the aircraft using
FANS-1/A message elements UM80, UM169, UM19, UM169 and UM123. These
message elements may all be sent within the same message, or a sub-set of the
elements may be sent in a message (see Appendix A for message samples).
The clearance will contain an intermediate level to maintain, a beacon code, the
SID/transition, and potentially the STAR/transition at the arrival airport. It will also
contain either the cleared route of flight in a loadable um80, or a freetext stating
CLEARED TO [destination airport] [SID] THEN AS FILED, and potentially the
STAR at the arrival airport (not Approach or Arrival Runway). No altitude or
2
c.
d.
e.
f.
g.
h.
i.
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. If DTAP encounters a situation where the uplink would require
transmission of more than 20 unpublished lat/long way points, the message will
be presented to the controller and the departure clearance will be delivered via
voice.
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 shall be
designated by a published named waypoint, or by the crossing point of that
airway and another consecutive airway in the RouteClearance.
9. The DTAP shall provide a courtesy copy message including required parts of the
clearance as defined in the the AOC Trials Functional Interface Document, excepting
beacon code, to the Airline Host via the airline-supplied 7-character ACARS address. The
courtesy copy shall include a header “DCL COURTESY COPY – NOT AN ATC
CLEARANCE”, and any contents sourced from the uplinked DCL clearance will be
decoded from ARINC622 format. 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.
10. 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 DM0[WILCO]. If unacceptable, or if a
3
“Partial Load” or “Load Failure” indication occurs, the crew downlinks DM1[UNABLE]. If a
DISCON is present when the clearance is loaded, and the aircrew cannot resolve the
DISCON, the crew downlinks DM1[UNABLE].
11. 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
with an AOC-built route. Therefore, other request functions shall be used for this data.
12. 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 12.b. and 12.d, above.
h. For UM79, when the “TO” point is also an airway termination point for an airway
that’s the last element in the routeinformation field, DTAP shall include the “TO”
point as the last element in the routeinformation field after the airway.
i. For UM83, when the “AT” point is also an airway entry point for an airway that’s
the first element in the routeinformation field, DTAP shall include the “AT” point
as the first element in the routeinformation field prior to the airway.
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.
13. The DTAP shall provide a courtesy copy message including required parts of the
clearance as defined in the the AOC Trials Functional Interface Document, excepting
beacon code, to the Airline Host via the airline-supplied 7-character ACARS address. The
courtesy Revision copy shall include a header “REVISED DCL COURTESY COPY –
NOT AN ATC CLEARANCE” and any contents sourced from the uplinked DCL clearance
will be decoded from ARINC622 format. 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
4
copy. The Airline Host shall ensure that the DCL Revision copy is not forwarded to the
aircrew/aircraft.
14. 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 DM0[WILCO]. If unacceptable, or if a
“Partial Load” or “Load Failure” indication occurs, the crew downlinks DM1[UNABLE]. If a
DISCON is present when the clearance is loaded, and the aircrew cannot resolve the
DISCON, the crew downlinks DM1[UNABLE].
15. 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.
5
Appendix A: Sample Messages
DCL Initial – AS FILED / THEN AS FILED
ENCODED MESSAGE (ARINC 622):
FMD
AN N623FE
- /AA
FMCBOCR.AT1.N623FE84D497C399160D28B110549E825C5AF49041934A84FA5516209B166A07
082245A082A488B39041A682349991624260FA2A4D62D8A08234C66E5820AF2503160826C99C82
0C6A882245A0B10448B41046A5168A062C9B2E64D5045890EA2062D59357B1723647
MESSAGE DESCRIPTION
 UM169 – “CLEARED TO ” (airportdestination) “ AIRPORT,“ (proceduredeparture) ”.”
(proceduretransition) “ “ [Climb-out procedure] {if applicable} “ THEN AS FILED”
 UM19 – [altitude]
 UM169 – “EXP ” (requestedaltitude) “ “ [minutes-miles] {“ MIN ” or “ MILES ” as determined by the
adapted value of [minutes-miles]} “AFTER DEP. DEP FREQ ” [frequency] “ EDCT ” (edcttime) {if
applicable}
 UM123 – (beaconcode)
UM
Number
UM169
[freetext]
UM19
MAINTAIN
[altitude]
UM169
[freetext]
ASN1
Definition
FreeText ::= IA5String
(SIZE (1..256))
Altitude ::= CHOICE
altitudeqnh [0]
altitudeflightlevel[6]
FreeText ::= IA5String
(SIZE (1..256))
UM123
SQUAWK
[beaconcode]
Code ::= SEQUENCE
SIZE (4) OF
BeaconCodeOctalDigit
::= INTEGER (0..7)
Sample Clearance
Notes
CLEARED TO KEWR AIRPORT,
MEM 8 DEP THEN AS FILED
MAINTAIN 10000FT
EXP FL390 WI 10 MIN
AFT DEP. DEP FREQ 126.25
EDCT 1525
FL/FT, MIN/MILES,
Freq is Ctrl selected
from DP, EDCT –
display if HADDS
provides
SQUAWK 0562
Filed Route – Crew has a paper copy of flight plan – Manual FMS input or AOC uplink of Filed Flt Pln:
KMEM.J29.ROD.J29.DORET.J584.FQM.FQM2.KEWR
Local adds the MEM 8 DEP
6
DCL Initial – Full Route Clearance
ENCODED MESSAGE (ARINC 622):
FMD
AN N623FE
- /AA
FMCBOCR.AT1.N623FE81286152E6C59B2E2D7A51C6A335928D4668605362CD8A532720A94F8
914A64E42449F4A2D48E53570D0146A337A9089B166A07082245A0260FA2A4DA2D8A08234C66
E5820AF2503160826C99C820C6A882245A0B90448B41046A5168A062C9B2E64D50208B121D440
C5AB26AF62E44EBA
MESSAGE DESCRIPTION
 UM80 – (airportdeparture) (airportdestination) (procedurearrival) (routeinformation)
 UM169 – (proceduredeparture) ”.”(proceduretransition) “ “ [Climb-out procedure] {if applicable}
 UM19 – [altitude]
 UM169 – “EXP ” (requestedaltitude) [minutes-miles] {“ MIN ” or “ MILES ” as determined by the
adapted value of [minutes-miles]} “ AFTER DEP. DEP FREQ ” [frequency] “ EDCT ” (edcttime) {if
applicable}
 UM123 – (beaconcode)
UM
Number
UM80
[RouteClearance]
UM169
[freetext]
UM19
MAINTAIN
[altitude]
UM169
[freetext]
UM123
SQUAWK
[beaconcode]
ASN1
Definition
AirportDeparture[0]
AirportDestination [1]
ProcedureArrival [6]
Routeinformation [8]
FreeText ::= IA5String
(SIZE (1..256))
Altitude ::= CHOICE
altitudeqnh [0]
altitudeflightlevel[6]
FreeText ::= IA5String
(SIZE (1..256))
Code ::= SEQUENCE
SIZE (4) OF
BeaconCodeOctalDigit
BeaconCodeOctalDigit ::=
INTEGER (0..7)
Sample Clearance
CLEARED ROUTE
CLEARANCE
7
KMEM
KEWR
FQM.FQM2
SEE RTE INFO below
MEM 8 DEP
MAINTAIN 10000FT
EXP FL390 WI 10 MIN
AFT DEP. DEP FREQ 126.25
EDCT 1525
SQUAWK 0562
Full route clearance:
MEM.J29.ROD.J29.DORET.J584.FQM.FQM2.KEWR
Local adds the MEM 8 DEP
Notes
FL/FT, MIN/MILES,
Freq is Ctrl selected from
DP, EDCT – display if
HADDS provides
8
DCL “Revised Clearance” – UM79 Example - Change in Departure procedure
ENCODED MESSAGE (ARINC 622):
FMD
AN N623FE
- /AA
FMCBOCR.AT1.N623FE84D485528B5A4D38B11052A9164F1224FA516A004001429D06A4B66C5
9A81C20891682C41063548B490449F4A2D4414A2D3A8827C6414A7D5A9150559D0E4419D1E2C
41307D088B6
MESSAGE DESCRIPTION
 UM169 - ”REVISED RTE”
 UM79 - (position) (routeclearance)
 UM169 - (proceduredeparture) ”.” (proceduretransition) “ “ [Climb-out procedure] {if applicable} “
AFTER “ (position) “ REST OF ROUTE UNCHANGED”
 UM19 – [altitude]
 UM169 – “EXP ” (requestedaltitude) [minutes-miles] {“ MIN ” or “ MILES ” as determined by the
locally adapted value of [minutes-miles]} “ AFTER DEP. “ {if applicable}, “DEP FREQ ” [frequency]
{if applicable}“. EDCT ” (edcttime) {if applicable}, “ SQUAWK “ (beaconcode) {if applicable}
UM
Number
UM169
[freetext]
UM79
CLEARED TO
[position] VIA
[routeClearance]
UM169
[freetext]
ASN1
Definition
FreeText ::= IA5String
(SIZE (1..256))
Position ::= CHOICE ::=
fixname
RouteClearance ::=
SEQUENCE
Routeinformation [8]
FreeText ::= IA5String
(SIZE (1..256))
UM19
MAINTAIN
[altitude]
Altitude ::= CHOICE
altitudeqnh [0]
altitudeflightlevel[6]
Amended Route:
KMEM..BNA..DORET.J584.FQM.FQM2.KEWR
Local adds the MEM 8 DEP
9
Sample Clearance
Notes
REVISED RTE
CLEARED TO DORET VIA
ROUTE CLEARANCE
MEM 8 DEP, AFTER DORET
REST OF ROUTE
UNCHANGED
MAINTAIN 10000FT
Routeinformation:
BNA (fixname)
DCL “Revised Clearance” – UM83 Example – Change in downstream route and
arrival procedure
ENCODED MESSAGE (ARINC 622):
FMD
AN N574FE
- /AA
FMCBOCR.AT1.N574FE825485528B5A4D38B11052A914533529F110A9716BD28E3519AC946A33
4102A53E202A14E1028D46687F95
MESSAGE DESCRIPTION
 UM169 – “REVISED RTE”
 UM83 - (position) (routeclearance)
 UM169 – “EXP “ (requestedaltitude) [minutes-miles] {“ MIN ” or “ MILES ” as determined by the
locally adapted value of [minutes-miles]} “ AFTER DEP. “ {if applicable}, “DEP FREQ “ [frequency]
{if applicable} “. EDCT ” (edcttime) {if applicable}, “ SQUAWK “ (beaconcode) {if applicable}
UM
Number
UM169
[freetext]
ASN1
Definition
FreeText ::= IA5String
(SIZE (1..256))
UM83
AT [position]
CLEARED
[routeClearance]
Position ::= CHOICE ::=
fixname
RouteClearance ::=
SEQUENCE
AirportDestination [1]
ProcedureArrival [6]
Routeinformation [8]
Sample Clearance
REVISED RTE
AT ROD CLEARED
ROUTE CLEARANCE
Original flight plan
KMEM.J29.ROD.J29.DORET.J584.FQM.FQM2.KEWR
Amended flight plan (change in red)
KMEM.J29.ROD..PSB..FQM.FQM2.KEWR
10
Notes
(routeclearance)
(airportdest) KEWR
(procarrival) FQM.FQM2
(routeinformation – 3
elements)
ROD, (fixname)
PSB (fixname)
FQM (fixname)
DCL “Revised Clearance” – UM80 Example – Full Route Clearance – Unable to
use previously cleared route
ENCODED MESSAGE (ARINC 622):
FMD
AN N623FE
- /AA
FMCBOCR.AT1.N623FE815485528B5A4D38B11052A91750C2A5C1A9325CC8F065973E952B2CD
459D3C3029142BC7298B9620A858A91CA62E5884A526247B31CA62E58828B3A7D485C49F3E65
96ABA24F9F32C898384A9418B628208D319B96082BC940C58209B26720831AA20891682E41122
D0411A945A2818B170B9AB54116243A88193168D5053A3560D796818356CCC8BA9
MESSAGE DESCRIPTION
 UM169 – “REVISED RTE”
 UM80 – (airportdeparture) (airportdestination) (procedurearrival) (routeinformation)
 UM169 - (proceduredeparture) ”.” (proceduretransition) “ “ [Climb-out procedure] {if applicable}
 UM19 – [altitude]
 UM169 – “EXP ” (requestedaltitude) [minutes-miles] {“ MIN ” or “ MILES ” as determined by the
adapted value of [minutes-miles]} {if applicable} “ AFTER DEP. DEP FREQ ” [frequency] {if
applicable} “. EDCT ” (edcttime) {if applicable} “ SQUAWK ” (beaconcode) {if applicable}
UM
Number
UM169
[freetext]
UM80
[RouteClearance]
ASN1
Sample Clearance
Definition
FreeText ::= IA5String REVISED RTE
(SIZE (1..256))
AirportDeparture[0]
CLEARED ROUTE
AirportDestination [1] CLEARANCE
ProcedureArrival [6]
Routeinformation [8]
UM169
[freetext]
UM19
MAINTAIN
[altitude]
UM169
[freetext]
FreeText ::= IA5String
(SIZE (1..256))
Altitude ::= CHOICE
altitudeqnh [0]
altitudeflightlevel[6]
FreeText ::= IA5String
(SIZE (1..256))
Notes
See new route below, repeat
Dept/Arr transition fix in the
route information string
DOOLY5.DOOLY
MAINTAIN 9000FT
EXP FLXXX WI 10 MIN
AFT DEP. DEP FREQ 118.55
EDCT 2145 SQUAWK 0562
New add to this UM169,
Squawk due to concatenation
limits
Original flight plan
KATL.UGAAA3.AHN.J208.HPW.J191.PXT.KORRY3.KLGA
Amended flight plan (change in red)
KATL.DOOLY5.DOOLY..HPW.J191.PXT.J191.RIDGY.J191.ENO.KORRY3.KLGA
11
DCL Courtesy Copy, FAA to Airline ground-to-ground message
^AQU ANPOCWN
.HOUTWXA 161300
^BCCI
001 COURTESY COPY - NOT AN ATC CLEARANCE
SWA9999 7421 KHOU
MD88/Q-SDG/S P1340
000 370
KHOU 30L SBI2 27R --- LGC2
LINGG YOKEM SBI LLA LEV
THEN AS FILED
EXPECT LEVEL F370
DEPARTURE SPEED M0.5
DEPARTURE HEADING 083DT
NO DELAY EXPECTED
FREQ 118.700
MAINT 5000
SQUAWK 7421
ATIS 124.6
^C
^A = STX = Start of text
^B = STH = start of header
^C = ETX = end of text
each line ends with CR/LF characters
12