Examples of ACK, CNL, CHG, DLA, and REJ Messages

ACK for FPL with Optional Message Number – ACK to Optional NADIN address vice FPF/AFTN address

US Airways (AFTN address KTULUSAD) filed for America West (NADIN address AWE). ACK or REJ response will be sent to NADIN address AWE, not AFTN address KTULUSAD. The complete rules for routing responses are as follows:

1. AFTN originator address must be adapted as answerable in the receiving center, or no response is provided.
2. If optional NADIN address in ICAO Field 03b is not adapted or not present, response is sent to AFTN originator.
3. If optional NADIN address is present in Field 03b and is adapted, response is sent to that address.

Input from US Airways

FF KZDCZQZX
231411 KTULUSAD
(FPLAWE/KZDC004-AWE603-IS
-A319/M-SDIW/C
-KBWI1230
-N0291F090 SWANN3 SWANN V214 DQO DCT
-KPHL0017
-RMK/DVRSN)

Output to AWE (Adapted in NADIN as KPHXAWED)

ACK FPL/004 KZDC AWE603 KBWI 1230 KPHL

ACK for FPL with Optional Message Number – ACK to Optional NADIN address vice FPF/AFTN address

If there is no Optional Message Number in Field 3b, the Aircraft ID, departure airport, departure time and destination airport are used to identify the flight.

Input from United Airlines

FF KZDCZQZX
1081714 KCHIUALE
(FPL-UAL1447-IS
-A320/M-SDGIRWZ/S
-KIAD2130
-N0360F360 DCT DAILY J61 HUBBS DCT KEMPR DCT ILM
AR21 CRANS FISEL2
-KFLL0206
-NAV/RNVD1E2A2)

Output to KCHIUALE

ACK FPL KZDC UAL1447 KIAD 2130 KFLL

REJ for invalid FPL

Field 15a (Cruising Speed) is invalid due to an illegal prefix (K). The REJ identifies the element and data in error, and provides the entire contents of the erroneous incoming message.

Input from Leesburg Flight Service Station

FF KZDCZQZX
1081714 KDCAYFYX
(FPLDCA/KZDC015-N57FC-IG
-C500/L-SDGWZ/C
-KDAN1530

-K0300F210 DCT FVX DCT

-KCHO0020
-IRMK/FRC RMK/PTP PATTERN WORK NAV/RNVE99)

Output to DCA

REJ FPL/015 KZDC SPD K0300F210 DCT FVX DCT FORMAT

FPLDCA/KZDC015-N57FC-IG-C500/L-SDGW/C-KDAN1530-K0300F210 DCT FVX DCT-KCHO0020-IRMK/FRC RMK/RNVE99

ACK for CNL with an Optional Message Number

This example shows cancellation by Pope AFB of a previously filed FPL; departure and destination are both KPOB. The CNL message number is 015 in the Optional Message Data (Field 3c), and it refers to message number 008 in the Optional Message Number (Field 3b) of the previous FPL. Note the message number can refer to a NADIN address (POP in this case) that is the same location as the AFTN originator (KPOBYXYX), so the response is returned to the originator.

Input from Pope Air Force Base

FF KZDCZQZX
231411 KPOPYXYX
(CNLPOP/KZDC015POP/KZDC008-FRTTN23-KPOB)

Output to POP

ACK FPL/004 KZDC AWE603 KBWI 1230 KPHL

REJ of CNL with Multiple Flight Plans

An Optional Message Number was not included in the CNL. The CNL will be rejected if more than one FPL exists with the same ACID, departure airport and destination airport.

Input from Delta Airlines

FF KZDCZQZX
231411 KATLDALW
(CNL-DAL1964-KDCA-KLGA)

Output to KATLDALW

REJ CNL KZDC MULTIPLE FLIGHT PLANS MANUAL COORDINATION REQUIRED

CNL DAL1964 KDCA KLGA

ACK for CHG filed without an Optional Message Number or Departure Time

If there is no Optional Message Number in Item 3b or departure time, the Aircraft ID, departure airport, and destination airport are used to identify the FPL; if no duplicate FPL exists, the CNL message will be acknowledged.

Input from DUATS

FF KZDCZQZX
251201 KIADXCLX
(CHG-N96747-KFDK-KDAN-15/N0110F080 DCT JYO DCT CSN DCT)

Output to KIADXCLX

ACK CHG KZDC N96747 KFDK KDAN

ARTCC Four-letter Location Identifiers for Domestic ICAO FPL Field 3b/c

Location identifiers in red (i.e., KZCA, KZCH, KZCL) shall not be filed anywhere other than in Fields 3b/c of a U.S. domestic ICAO flight planning message. The location identifiers below will be included in Acknowledgement (ACK) and Rejection (REJ) messages to indicate the source of the message.

Abbreviations Used in REJ Messages

GNSS Library - Documents