FAA/ATCSCC

APRIL 1997

FEDERAL AVIATION ADMINISTRATION

AIR TRAFFIC CONTROL SYSTEM COMMAND CENTER

ESTIMATED DEPARTURE CLEARANCE TIME \[EDCT\]

AUTOMATED SUBSTITUTION \[SI\] MESSAGE PROCESSING

The Substitution process is available to the user during a ground delay
program. A user may reassign a Controlled Time of Arrival (CTA) slot by
cancelling the flight assigned and substituting another. The CTA of the
second flight can then be used by a third flight \[and continuing for
the remaining slots\]. A second option is to exchange the CTA slots of
two flights. A third option is to adjust a flight's departure time while
retaining the assigned CTA slot. Following are detailed instructions for
the user to participate in the automated SI program.

**1. AIRLINE INPUT**

Requests for automated substitution processing must be transmitted to
the Air Traffic Control System Command Center (ATCSCC) ARINC address
TFMBSYA. Messages sent to other addresses will NOT be processed.

The 3-letter airline identifier is validated with a table of authorized
ARINC addresses. If the address of the requester is not in the table,
processing will terminate; an error message will be returned to the
sender.

SAMPLE INPUT SUBSTITUTION MESSAGE

(SENT BY AIRLINE TO ARINC ADDRESS TFMBSYA, PRIORITY=QU)

=========================================================

LINE 1= SI (Must be first line/first column of message)

LINE 2= xxx (Where xxx = arrival airport)

LINE 3=STATUS FLIGHT DEP PTIME EDCT ETA DF CTA ODF

CNX FAA1 PHL P2000 2040 2130 40 2210 40

SUB FAA2 CLE P2130 2130 2210 0 2210 20

END

SI RPL FAA2 CLE P2130 2150 2210 20 2230 20

DATA: SUB FAA3 ORD P2000 2010 2220 10 2230 30

END

RPL FAA3 ORD \...\....ETC\...\.....

SUB FAA\...\...\...\...\....ETC\...\.....

END

EXC FAA8 PHL P2000 2110 2130 70 2240 40

EXC FAA9 CLE P2130 2130 2210 0 2210 30

END

ADJ FAA10 CLE P2000 2000 2200 0 2220 20

END

LAST LINE= DISPATCHER-NAME AIRLINE-NAME PHONE-NUMBER

=========================================================

NOTE: Allow at least one space between columns.

Results of the above example:

Flight #1 is cancelled.

Flight #2 is assigned the 2210Z arrival slot vacated by flight #1.

Flight #3 is assigned the 2230Z arrival slot vacated by flight #2.

Flights #8+9 are assigned the new EDCT/CTA times indicated. \[Their CTA
slots were exchanged.\]

Flight #10 is assigned the adjusted EDCT time of 2000Z to arrive at the
assigned CTA time of 2220Z.

**2. EXPLANATION OF FIELDS IN INPUT RECORD**

LINE 1: Enter SI to identify the ARINC message as a substitution
request.

LINE 2: Enter the arrival airport in place of \'xxx\'. If a ground delay
program is not in effect for the airport, an error message will be
returned to the sender.

LINE 3: Enter column heading information as shown.

SI DATA: See below **\*\***. Spacing: Allow at least one space between
fields.

LAST LINE: Enter the name of the dispatcher, the company name, and the
telephone number.

\-\-\-\-\-\-\--

**\*\*** SI DATA:

**FIELD 1/STATUS:**

Enter one of the following requested actions.

-   **ADJ** (Adjust) - ADJ indicates that the Estimated Departure
    Clearance Time is adjusted to meet the Controlled Time of Arrival
    (CTA) slot assigned. An ADJ request must be followed on the next
    line by END.

-   **CNX** (Cancel) - CNX indicates that a flight is to be cancelled.
    To use the vacated CTA slot, the CNX request must be followed by a
    SUB request and END.

-   **EXC** (Exchange) - EXC indicates that the Controlled Time of
    Arrival (CTA) slots of two flights are to be exchanged. An EXC
    request must be followed by another EXC request and END. The revised
    EDCT and CTA times must be indicated in each EXC line.

-   **RPL** (Replace) - RPL indicates that the original CTA arrival time
    slot of this particular flight is available and is to be used by the
    following SUB flight. The RPL flight was already used in a SUB
    action, resulting in an open slot available for SUB action. RPL and
    SUB must be followed by END.

-   **SUB** (Substitute) - SUB indicates that a flight will use the
    arrival time slot of the preceding cancelled (CNX) or replaced (RPL)
    flight. The SUB action must be preceded by a CNX or a RPL action and
    followed by END.

-   **END (**End of Requested Transaction) - END indicates the end of a
    pair of SI requests or the end of a single line ADJ request. Valid
    combinations are:

-   To adjust the departure slot of a flight (no change to CTA)

    ADJ

    END

-   To exchange arrival slots of 2 flights

    EXC

    EXC

    END

-   To cancel a flight + substitute another

    CNX

    SUB

    END

-   To replace a flight + substitute another

    RPL

    SUB

    END

    NOTES:

-   The RPL/SUB\...RPL/SUB\... series must be started by a CNX/SUB
    action to create an open arrival slot. The CNX may have been
    approved in an previously submitted SI message.

-   EXC/EXC will exchange the arrival slots of two flights; no vacant
    slot is created.

-   ADJ will adjust the EDCT of a single flight; the CTA does not
    change. No CNX/SUB action is required.

    **FIELD 2/FLIGHT** (Aircraft Identifier): Enter the flight to be
    processed. Do NOT leave spaces between the airline identifier and
    the flight number. Do not use leading zeros in the flight number.

    **FIELD 3/DEP** (Departure Airport): Enter the departure airport
    identifier as specified in the ground delay program.

    **FIELD 4/PTIME** (Proposed Departure Time): Enter the proposed
    departure time (prior to assigned delays). The PTIME must be in
    Coordinated Universal Time (UTC) and may be prefixed with either the
    character \"P\" (Proposed) or \"S\" (Scheduled).

    **FIELD 5/EDCT** (Estimated Departure Clearance Time):

    CNX and RPL actions - Enter previously assigned EDCT.

    SUB/EXC/ADJ actions - Enter the new EDCT (in UTC) which is requested
    by the airline.

    **FIELD 6/ETA** (Estimated Time of Arrival): Enter the time (in UTC)
    that the flight was scheduled to arrive at the airport (prior to
    assigned delays).

    **FIELD 7/DF (**Delay Factor): Enter the delay in minutes.

    CNX and RPL actions - Enter the previously assigned delay.

    (NOTE: For CNX-or-RPL, this is the same as FIELD 9/ODF.)

    SUB/EXC/ADJ actions - Enter the new delay requested by the airline.

    **FIELD 8/CTA** (Controlled Time of Arrival):

    CNX/RPL/ADJ actions - Enter the previously assigned CTA (UTC).

    SUB and EXC actions - Enter the revised CTA (UTC) requested by the
    airline.

    The new CTA must be within a window from 0 minutes before to 20
    minutes after the CTA of the CNX-or-RPL-or-EXC flight.

    **FIELD 9/ODF** (Original Delay Factor): Enter the previously
    assigned delay (in minutes). (NOTE: For CNX-or-RPL, the numbers in
    the DF and ODF fields are the same.)

    NOTE: Fields 5/EDCT, 7/DELAY, 8/CTA, and 9/OLD-DELAY must reflect
    the most recently approved substitutions if more than one
    substitution action has been taken on a flight.

    **3. EDIT CHECKS**

-   Message Format

-   ..Address message to TFMBSYA, priority QU.

-   ..First line is SI (starting in column 1).

-   ..Second line is the arrival airport.

-   ..Third line is the heading information.

-   ..All lines begin in column 1.

-   ..Allow at least one space between fields.

-   ..Do not leave a space between the airline and flight number.

-   ..Do not use leading zeros in the flight number.

-   ..EXC must be followed EXC and END.

-   ..CNX must be followed by SUB and END.

-   ..RPL must be followed by SUB and END.

-   ..ADJ must be followed by END.

-   ..RPL/SUB \... RPL/SUB series must have started with a CNX/SUB
    action to create an open arrival slot. \[CNX may have been approved
    on a previously submitted request.\]

-   CTA Window

> The requested CTA of the SUB-or-EXC flight must be within a window
> from 0 minutes before to 20 minutes after the vacated CTA slot which
> it is filling (i.e., the preceding CNX or RPL flight or the companion
> EXC flight).

NOTES:

Multiple Requests: For more efficient processing, send multiple requests
(up to 15 pair) in a message. The size of the message is limited by the
maximum message length set by ARINC. Since requests may be based on
earlier substitutions, the user must wait for confirmation before
sending a subsequent batch. Otherwise, if an error is encountered in the
first batch, the follow-on batch will be rejected and have to be
resubmitted.

Error Processing: Message processing will terminate if an error is
encountered during SI processing. Airlines will receive confirmation of
the substitutions approved prior to the error, followed by the error
message for the rejected flight.

**4. OUTPUT**

a\. AIRLINES/ATCSCC - The response is sent to the return address on the
incoming message.

> NO ERRORS: If the requested substitutions pass the edit checks, a list
> with the revised EDCT\'s is sent to the airline via ARINC. A sample is
> shown below. (xxx is the arrival airport.)
>
> ACT ACID DEP EDCT CTA ARR
>
> CNX: FAA1 PHL 2040 2210 xxx
>
> SUB: FAA2 CLE 2130 2210 xxx
>
> SUB: FAA3 ORD 2010 2230 xxx
>
> EXC: FAA8 PHL 2110 2240 xxx
>
> EXC: FAA9 CLE 2130 2210 xxx
>
> ADJ: FAA10 CLE 2000 2220 xxx
>
> \*\*\* END OF SI MESSAGE \*\*\*
>
> ERRORS: If an error is encountered, processing will stop. An error
> message (with a listing of the valid substitutions approved PRIOR to
> the error) is sent to the airline. The error should be corrected and
> resubmitted. A sample is shown below.
>
> ACT ACID DEP EDCT CTA ARR
>
> CNX: FAA1 PHL 2040 2210 xxx
>
> SUB: FAA2 CLE 2130 2210 xxx
>
> \*\*SI ERROR - FAA3 NOT FOUND FOR RPL. SI TERMINATED
>
> \*\*\* END OF SI MESSAGE \*\*\*
>
> b\. CENTER TMU: A message listing the approved changes is sent to the
> Center TMU via ETMS. The list contains flights departing from that
> Center. (Error messages will NOT be included.) This message is for TMU
> information. A sample is shown below. The flight strip will contain
> the revised EDCT. If the strip has already been printed, an amended
> EDCT time will be issued.
>
> FLIGHTS REVISED BY SI FOR xxx
>
> ACT ACID DEP C EDCT CTA ARR
>
> SUB: FAA3 ORD G 2010 2230 xxx
>
> \*\*\* END OF SI MESSAGE \*\*\*
>
> (\'C\' column indicates the departure Center.)

**5. REPORTS:** Three related reports are available to the user through
the SI process. An error message will also be generated if the 'LAST
LINE' information is not included with the request.

> **a. [CTALIST]{.underline}** is a list of all
> controlled/cancelled/open flights at the selected airport for the
> requesting airline/subcarriers. The flights with vacated open slots
> will show the open slot time available for substitution \[for use in a
> RPL action\]. Flights cancelled by SI actions are listed at the bottom
> of the report.
>
> \(1\) Input:
>
> LINE 1= SI (Must be first line/first column of message)
>
> LINE 2= xxx (Where xxx = arrival airport)
>
> LINE 3=STATUS FLIGHT DEP PTIME EDCT ETA DF CTA ODF
>
> REQ CTALIST
>
> END
>
> LAST LI NE= DISPATCHER-NAME AIRLINE-NAME PHONE-NUMBER
>
> \(2\) Output:
>
> [REPORT FORMAT]{.underline}
>
> CONTROLLED FLIGHTS FOR xxx
>
> IDENT DEP DEPT EDCT CTA OPEN
>
> FAA1111 DEN S2200 C2300 A0100
>
> FAA2222 ORD S2300 C2358 A0212 0232
>
> FAA3333 DFW S0300 C0400 A0600 0645
>
> CANCELLED FLIGHTS FOR xxx
>
> IDENT DEP
>
> FAA444 DCA
>
> FAA555 IAD
>
> **b. [SLOTS]{.underline}** is a list of all current open slots at the
> selected airport for the requesting airline/subcarriers. These are
> flights which have been successfully substituted, leaving an available
> CTA slot open.
>
> \(1\) Input:
>
> LINE 1= SI (Must be first line/first column of message)
>
> LINE 2= xxx (Where xxx = arrival airport)
>
> LINE 3=STATUS FLIGHT DEP PTIME EDCT ETA DF CTA ODF
>
> REQ SLOTS
>
> END
>
> LAST LINE= DISPATCHER-NAME AIRLINE-NAME PHONE-NUMBER
>
> \(2\) Output:
>
> [REPORT FORMAT]{.underline}
>
> OPEN SLOTS FOR xxx
>
> IDENT DEP DEPT EDCT CTA OPEN
>
> FAA2222 ORD S2334 C2358 A0212 0232
>
> FAA3333 DFW S0300 C0400 A0600 0645
>
> **c. [CNX]{.underline}** is a list of all flights cancelled for the
> selected airport for the requesting airlne/subcarriers. These are
> flights which have been cancelled through the SI process.
>
> \(1\) Input:
>
> LINE 1= SI (Must be first line/first column of message)
>
> LINE 2= xxx (Where xxx = arrival airport)
>
> LINE 3=STATUS FLIGHT DEP PTIME EDCT ETA DF CTA ODF
>
> REQ CNX
>
> END
>
> LAST LINE= DISPATCHER-NAME AIRLINE-NAME PHONE-NUMBER
>
> \(2\) Output:
>
> [REPORT FORMAT]{.underline}
>
> CANCELLED FLIGHTS FOR xxx
>
> IDENT DEP
>
> FAA444 DCA
>
> FAA555 IAD
>
> **d. [MULTIPLE REPORTS]{.underline}:** One, two, or all three reports
> for a single airport can be requested in a single message. The REQ
> statements cannot be combined in a message with other SI statements
> \[CNX/SUB/RPL/ADJ\].
>
> \(1\) Input:
>
> LINE 1= SI (Must be first line/first column of message)
>
> LINE 2= xxx (Where xxx = arrival airport)
>
> LINE 3=STATUS FLIGHT DEP PTIME EDCT ETA DF CTA ODF
>
> REQ CTALIST
>
> END
>
> REQ SLOTS
>
> END
>
> REQ CNX
>
> END
>
> LAST LINE= DISPATCHER-NAME AIRLINE-NAME PHONE-NUMBER
>
> \(2\) Output: Each report will be sent to the user as a separate
> message.