Alternate Routes

Function presentation

This functionality displays a list of alternate routes for a selected flight.
On selection of one of the proposed alternate routes, the user will be able to :

  • Request the evaluation of a possible rerouting.
  • Immediately request to reroute the flight without a first evaluation.
  • Request to reroute based on the returned evaluation.


Access to alternate route listing, reroute evaluation, execution, generate and add will be restricted by security profile.

Opening the window

From the Application / ATFCM menu, select the option Flights / Alternate Routes.

A new empty Alternate Routes window will be opened with the following defaults :

  • IOBD : current or last queried traffic date is proposed (relative to current UTC date) depending on selected user preference (CHMI / ATFCM application / General / Dates and times / Default date proposed for query).
  • IOBT : blank. Drop-down list will propose pre-formatted time on a 20 minutes step base.
  • ARCID : the drop-down box will propose the most recent query data elements you have queried before with success.
  • ADEP : the drop-down box will propose the most recent query data elements you have queried before with success.


On initial display, the focus is set on the first mandatory query control with no default value: the ARCID input control.

Preparing to query

The Initial Estimated Off Block Date (IOBD) may be adjusted to one of the proposed values. Common ATFCM Tactical / Pre-Tactical dates behaviour is implemented.
The Initial Estimated Off Block Time (IOBT) input box shall be adjusted to a valid time value from 00:00 to 23:59 included. This time does not have to be exact. The system allows some flexibility to identify the precise flight you want to query.
The Aircraft Identifier (ARCID) shall be filled in or selected from the drop-down list (when a previous query was successful).
The Aerodrome of Departure (ADEP) shall be filled in with an Aerodrome ICAO code or selected from the drop-down list (when a previous query was successful).
All these query data elements are mandatory in order to identify a unique flight.
The Send button will send the query to the CFMU system.
This window may be closed before any query is issued.
The Reset action common functionality is implemented for this function. All query criteria are considered for activating the Reset action.

Displaying the query results

This display shows the list of alternate routes for the Flight that corresponds to the selected query crieria.
The title contains the time stamp when the information was retrieved from the CFMU system.
The header section of the window contains the different query data elements used to retrieve the displayed alternate routes :

  • IOBD : Initial Estimated Off Block Date.
  • IOBT : Initial Estimated Off Block Time possibly adjusted to its correct value based on the query results data.
  • ARCID : Aircraft Identifier.
  • ADEP : Aerodrome of Departure.


The Aerodrome of Destination (ADES) is displayed in the header section when the reply is received from the CFMU system.
On query results display, the focus is set on the alternate route list after selecting the first entry in the list.
The frame below the header section displays the following details for the selected flight :

  • the Estimated Take Off Time,
  • the Calculated Take Off Time, if appropriate,
  • the Calculated Shift+Delay, if appropriate,
  • the Estimated Elapsed Time of the flight,
  • the Most Penalising Regulation, if any and possibly if Other regulations apply,
  • the ICAO identifier of the Aircraft Type,
  • the Initial Requested Level,
  • the initial true airspeed in Kilometers per hour (K), Nautical Miles per hour (N) or Mach number (M) (Initial Requested Speed),
  • the current Route Length in miles.


The description of the current route (FPL field 15 - Point Sequence) is not available for display.
Finally, the next part of the window proposes the possible alternate routes.
At the top of the alternate route list, a counter indicates the number of alternate routes retrieved.
This counter may be affected by filtering (fff / rrr Alternate Routes where fff is the filtered number and rrr is the retrieved number).
The main listbox contains the list of proposed Alternate Routes.
The CFMU system will return all potential alternative routes for the selected flight.
For each alternate route, the following information is displayed :

  • the Route ID (see later),
  • the worst CDR applied to this route (C) (see later),
  • the length of the proposed alternate route in Nautical Miles (NM) and the difference with the current route (Diff),
  • the Type of route (see later)
  • the other columns are only filled in after a "Try" or "Apply" function. The presence of the different columns will depend on the evaluation results.


Other columns are used to display the Alternate Route evaluation results. See later Reroute Evaluation section for a detailed description.
The Route ID is composed of:

  • the route origin (Aerodrome),
  • the route destination (Aerodrome)
  • and the Standard Route sequence number: For Generated route the sequence number shall be preceded by ‘G’ (e.g.: “LFPG EBBR G01”). For Manually entered route thesequence number shall be preceded by ‘U’ (E.g.: “LFPG EBBR U01”).

Possible CDR types are:

  • 0 when the ATS route. Closure is published in AUP part 'B' and CRAM.
  • 1 for permanently plannable conditional route. Closure is published in AUP part 'B' and CRAM.
  • 2 for non permanently plannable conditional route. Opening can be published in a CRAM.
  • N for not available - non plannable.

Type of route:

  • SR Standard Route.
  • GR Generated Route.
  • UR User Route.

On initial display, the list is sorted with the following priority from top to bottom

  • Generated Route by ascending order on Route Id.
  • Manually entered routes by ascending order on Route Id.
  • Standard routes by ascending order on Route Id.


Selecting one of the proposed alternate routes will display:

  • the description of the rerouted part as a point sequence using the FPL presentation. The full route description of the rerouted flight will only be available after an evaluation using the "Try FPL" or the "Apply" and if IFPS could generate the full route details.
  • the Cruising Speed / Level currently associated with this alternate route. The initial value corresponds to the default provided by the TACT system. The user may overwrite these default values by using the Reroute Preparation screen. (see later section on Reroute Preparation for more details)
  • the Remark associated to the Standard Route.

The Max Shift+Delay initially displays the greatest value accepted by the CFMU system.

  • This value may be overwritten with the greatest number of minutes representing the Maximum Shift+Delay accepted by the user for the rerouted flight.
  • The application will check that the overwritten value is between 0 and the maximum identified by the CFMU system.
  • An error message with the corresponding reason will be returned if this limit cannot be respected.

The Standard filter boxes is initially on.

The Manual and Generated filter box are initially off

The Manual and Generated filter box are automatically set to on, when the corresponding action is used to add routes to the list.:

  • ADD for Manual filter box.
  • Generate for Generated filter box.

When a filter box is unchecked, the corresponding items are filtered out from the list, even if currently selected.

User interactions

Alternate Routes

Click on a line to select an Alternate Route to have more detailed information displayed in the Standard Route details pane (bottom pane).
The following options are only displayed and active if the selected flight satisfies the conditions implemented in the CFMU system to accept a rerouting (Shift+Delay, suspended, IFPS zone coverage,...).
When a line is selected in the list of Alternate Routes, the right mouse button pops up a contextual menu.
This popup menu lists the possible actions for the selected Alternate Route:

  • Plot Route: The display of the selected alternate route on the map.
  • Plot All Route: The display of all alternate routes on the map.
  • Reroute Preparation : The display of the Reroute Preparation screen.
  • Reroute Try : The immediate evaluation of that route.
  • Reroute Try FPL : The immediate FPL evaluation of that route.
  • Reroute Apply : The immediate Rerouting using that route.
  • Reroute Apply File : The immediate Rerouting using that route and filing of the necessary IFPL.

Following user preference may be adjusted to associate a colour with the selected route(s) when displayed on the map : CHMI / ATFCM application / Flights / General / Alternate Route colour.  The default is white.

The following additional options are only included and active in the menu if the selected flight satisfies the conditions implemented in the CFMU system to accept a rerouting (Shift+Delay, suspended, IFPS zone coverage,...).

Access to the different evaluation and reroute functions will be restricted by security profile.
When issuing an immediate "Try" or "Apply", the Reroute Preparation dialog is not proposed. Consequently the application will use the last updated Flight Speed / Level list. See the Reroute Preparation section for more details on updating Flight Speed / Level list. If no updated list is available, the default values will be used for the flight. (Cruising Speed / Flight Level)
To update the display, click on the Send button on the button bar or select the Action / Send menu option. This will issue exactly the same query to obtain an up to date alternate route list. Be careful, all previous evaluation data will be lost in order to provide a fresh display.
To print the alternate route list, first retrieve, sort and filter the data in the window. When ready, click on the Print button or select the File / Print menu option.
To display a sub-selection of the retrieved data, click on the Filter button on the button bar or select the Action / Filter menu option and adjust the desired filtering criteria.
To modify the Sort sequence of the alternate routes, click on column headers corresponding to your desired sort criteria.
To export the displayed details, click on the Export button or select the Action / Export menu option.

Add user routes

The Add button allows the user to enter its own route. This function is only available for flight which has its “AO What if Reroute” indicator code (W) set to T (Try allowed) or A (Apply and Try allowed). It opens the Reroute Preparation screen(C.f: Reroute Preparation).

The Manual filter box is automatically ticked after a route was manually added.

The created route is added to the list of alternate route with a route Id. These routes are presented into the list in ascending order on Route Id, before the Standard routes but after the Generated route.

Ask for generated routes

The Generate button allows the Operator to request to the CFMU system dynamically generated routes.

The Via Point, Via Airspace, Avoid Point and Avoid Airspace field allow the Operator to specify constraints on the routes to be generated:

  • Via Point: PublishedPoints the proposed route shall over fly.
  • Via Airspace: Airspace (2D projection) the proposed routes shall traverse
  • Avoid Point PublishedPoints the proposed routes shall avoid.
  • Avoid Airspace: Airspace(2D projection) the proposed routes shall avoid.

The generated routes already present from a previous request are removed from the list of alternate routes. The newly generated routes returned by the CFMU system will be added to the list of alternate routes with a route Id as defined in [ATFCM.CHMI.ALTRT.DISPLAY.015]. The number of generated route might be limited by the server to preserve performances (initially limited to 5). These routes are presented into the list in ascending order on Route Id, at the top of the list of alternate routes.

 

Reroute Preparation

The Reroute Preparation screen is an optional intermediate screen in the evaluation process.
Once the list of possible alternate routes is retrieved from the CFMU system for the selected flight, if it is reroutable and the user is authorised to the reroute functions, the Reroute Preparation dialog may be invoked for one of the proposed alternate routes or via the Add button.

This is a modal dialog box ! It means that when it is opened, no other function can be invoked.
This dialog allows to update :

  • The route description: cruising speed and level, but also the route itself
  • The Maximum Shift+Delay accepted by the user for the new route.
  • The associated network address.


The header section contains the selected query criteria used to identify a unique flight :

  • the Initial Estimated Off Block Date (IOBD),
  • the Initial Estimated Off Block Time (IOBT).
  • the Aircraft identifier (ARCID),
  • the ICAO code for the Aerodrome of Departure (ADEP).


The Aerodrome of Destination is displayed for information (ADES).
The Standard Route ID is inserted as the title of this header section.
Next to this ID, the stamp of the possible previous evaluation processing time.

When opened from the Add button, the Route Description Edit is empty.

The Route Description Edit shall allow Copy/Paste functionality.

The “Result of previous action” box gives more details on the selected alternate route with possibly the results of a previous evaluation.

  • Any relevant error message described above in the Reroute Evaluation section.
  • the description of the rerouted part as a point sequence using the FPL presentation. Replaced by the detailed description (ICAO flight plan) of the full route, if a "Try FPL" function was invoked before and if IFPS could generate the full route details.
  • the Remark associated to the Standard Route.

Before requesting a "Try" or an "Apply" on this alternate route, the Operator has the possibility to update the following data elements :

  • The Max Shift+Delay may be overwritten with the greatest number of minutes accepted by the user for the new Shift+Delay value. A maximum value is imposed by a CFMU parameter. The proposed default is this maximum or the last queried Max Shift+Delay value. An error message will be returned if this limit cannot be respected.
  • The network address to be associated with this terminal. This information is mandatory for all "Try" and "Apply" actions. If a default AFTN or SITA address is defined, it is presented in the Originator Address drop-down box. To have a default address defined, you need to update the Message Originator preferences (CHMI / ATFCM application / General / Origin / Default Address ID).
  • The Route description may be adjusted by the user.

Following possibilities are given to the user for Route description Edit :

  • No Update in which case the route will be used as proposed by the CFMU system or as previously created.
  • The Operator changes the Route Description:
    • In the case the Reroute Preparation was opened from a Generated or Standard alternate route or from the Add button, a new Manual route is created. A new line will be added to the alternate route list after having performed a Try or Apply operation.
  • When Reroute Preparation is opened from a Manual route already in the alternate route list, it is replaced by the modified one.

The local ATFCM CFMU Interface will only process syntax checks to validate the entered points. The CFMU server will perform further context editing.

Click on the AFTN or SITA radio button to select the address type.

You may introduce an address in the corresponding box or select another one in the list by clicking on the button to drop-down the list. Any address will be checked for a valid syntax.

To request a Shift+Delay evaluation only with no IFPS flight plan validation, click on the Try button.

To request a full reroute evaluation including FPL validation in IFPS, click on the Try FPL button.

To request an immediate booking if the selected reroute pass validation with the provided parameters (Max Shift+Delay and Route Description) click on the Apply button. The Operator will then have to file the flight plan by himself.

Click on the Apply / File button to request an immediate booking and filing. If the selected reroute is successfully validated with the provided parameters (Max Shift+Delay and Route Description), the slot will not only be booked in the CFMU system, but the corresponding flight plan will be filed automatically in IFPS.

To close this Reroute Preparation dialog without any "Try" or "Apply", click on the Cancel button. This action will ignore the updates made on this preparation window, if any.

Some buttons may be disabled for the following reasons:

  • The flight, checked by ETFMS, does not meet all requirements.
  • The user has a limited security profile.

 

Reroute Evaluation

This section describes the functionality implemented to request the evaluation of possible reroutings.
This functionality is available only if following conditions are met:

  • The flight satisfies the conditions implemented in the CFMU system to accept a rerouting evaluation.
  • The users' security profile allows him to apply this functionality.


Based on the previous conditions the user is allowed to invoke the "Try" functionality to request the evaluation of possible reroutings through following windows:


Once the list of possible alternate routes is retrieved from the CFMU system for a selected flight, the evaluation of routes may be requested.
The evaluation process may only be requested for one route at a time to preserve performance.
On selecting an alternate route, the Max Shift+Delay input box is initialised :

  • With the greatest Shift+Delay time accepted by the CFMU system to perform a rerouting action, if this route was not yet evaluated.
  • With the last updated Max Shift+Delay value used, if this route was already evaluated.


Before requesting a rerouting evaluation, the user may overwrite the content of the Max Shift+Delay input box with the maximum number of minutes he is ready to accept as the new Shift+Delay for the flight.
The "Try" and "Apply" functions will reject a Maximum Shift+Delay if it is greater than the one authorised by the CFMU system.
The network address to be associated with this terminal is mandatory for the "Try" and "Apply" actions.
To have a default address defined, you need to update the Message Originator preferences (CHMI / ATFCM application / General / Origin / Default Address ID).
To request a reroute evaluation for the flight, select the desired Alternate Route in the list and press the right button of the mouse. Select one of the following contextual popup or action menu options :

  • Reroute Preparation : to request the display of the Reroute Preparation screen. It is used to input input route description updates, Maximum Shift+Delay and/or associated network address..
  • Reroute Try : for an immediate Shift+Delay evaluation without IFPS verification.
  • Reroute Try FPL : for an immediate FPL evaluation including IFPS verification.


The Reroute Preparation screen is an optional intermediate screen in the evaluation process.
This preparation screen will mainly allow the user to modify the flight level and the speed information before submitting the "Try" or the "Apply" request.
The Reroute Preparation screen is described in an earlier section of this document.

Once a route has been successfully evaluated, the "Reroute Evaluation" results are added in the alternate route list Details pane:

  • The Status column (S) indicates the result of Reroute Evaluation process (see list below).
  • The new Take Off Time (TOT). After the time, a letter "C" for Calculated indicates that using this new route, the flight is subject to regulation. A letter "E" for Estimated indicates that the flight is out of any regulation.
  • The resulting new calculated Shift+Delay value, if any (S+Delay). The presence of asterisks in this column indicates provisional delays (i.e. '*12*').
  • The difference in minutes compared to the current Shift+Delay (Diff).
  • The Estimated Elapsed Time (EET) of the flight based on the new route.
  • The difference in minutes compared to the current EET (Diff).
  • The length of the new Route in Nautical Miles (NM).
  • The difference in Nautical Miles compared to the current length (Diff).
  • The identifier of the Most Penalising Regulation based on the new profile, if any (REGUL+).


Here follows the list of possible Reroute Evaluation Status:

  • The letter "T" indicates that a successful "Try" was processed by the CFMU system.
  • The letter "F" indicates that a successful "Try FPL" was processed by the CFMU system.
  • The letter "E" indicates that the Reroute Evaluation ended with an error message.


Selecting the evaluated alternate route will display additional details in the Details pane at the bottom.

  • A time stamp when the route evaluation request was processed and the rerouting request error reason, if any (see list below).
  • An error message returned by the TACT system, if applicable.
  • The description of the rerouted part as a point sequence using the FPL presentation. If the "Try FPL" function was invoked with success (IFPS could generate the full route details), the FPL presentation is replaced by the detailed description (ICAO flight plan extract) of the full route. In this case, the preceding static text "Standard Route details:" is suppressed.
  • Exceptional condition with the Traffic Volume ID and the Runway Visual Range (RVR) value, if applicable.
  • The Overloaded Traffic Volume ID, if applicable.
  • The list of IFPS error messages (i.e. "Point for Speed / Level update not found in route details", ...), if applicable.


In case the Reroute Evaluation process did not succeed, one of the following error reasons will be displayed next to the process stamp :

  • Wrong input with the justification message on the next line.
  • Suspended if the flight is suspended.
  • Route not for flight if the requested alternate route is not valid for the flight.
  • Not authorised if you are not authorised to perform the requested action.
  • Overload with the overloaded Traffic Volume
  • Not IFPS compliant and the corresponding IFPS messages for rejection
  • Bad Shift/Delay for an excessive new Shift+Delay value.
  • Not available if rerouting function has been deactivated by the TACT system.
  • Already a proposal when there is already a rerouting proposal accepted for the selected flight.
  • Other TACT Error with the justification message on the next line.

Remark these rerouting evaluation results are informative and related to the precise time when they were initially calculated.
Remark there is no certitude on the final slot attribution because it depends on the elapse time between the calculation and the final rerouting decision.

Rerouting request

This section describes the functionality implemented to request a rerouting.
This functionality is available only if following conditions are met:

  • The flight satisfies the conditions implemented in the CFMU system to accept a rerouting.
  • The users' security profile allows him to apply this functionality.


Based on the previous conditions the user is allowed to invoke the "Apply" functionality to request the evaluation of possible reroutings through following windows:


Once the list of possible alternate routes is retrieved from the CFMU system for a selected flight, a rerouting may be requested immediately or after one or more initial evaluations.
The Rerouting request is limited to one successful process per flight.
On selecting an alternate route, the Max Shift+Delay input box is initialised :

  • With the greatest Shift+Delay time accepted by the CFMU system to perform a rerouting action, if this route was not yet evaluated.
  • With the last updated Max Shift+Delay value used, if this route was already evaluated. Before issuing a rerouting request, the Max Shift+Delay input box may be overwritten with the maximum number of minutes accepted by the user as the new Shift+Delay for the flight.

The "Apply" functions will reject a maximum Shift+Delay if it is greater than the one authorised by the CFMU system.
The network address to be associated with this terminal is mandatory for the "Try" and "Apply" actions.
To have a default address defined, you need to update the Message Originator preferences (CHMI / ATFCM application / General / Origin / Default Address ID).
To issue a reroute request for the flight, select the desired Alternate Route in the list and press the right button of the mouse. Select one of the following contextual popup or action menu options :

  • Reroute Preparation : to request the display of the Reroute Preparation screen. It is used to input Route description updates, Maximum Shift+Delay and/or associated network address.
  • Reroute Apply : for an immediate booking if the selected reroute pass validation with the provided parameters (Max Shift+Delay, Speed / Level Update and associated network address). This "Apply" will only reserve a slot in the CFMU system but the Operator has still to file the new flight plan via AFTN / SITA.
  • Reroute Apply File : for an immediate booking including filing of the new flight plan in IFPS. The selected reroute must pass validation with the provided parameters. (Max Shift+Delay, Speed / Level Update and associated network address).


This route may have been evaluated or not before its booking.
The Reroute Preparation screen is an optional intermediate screen in the evaluation process.
This preparation screen will mainly allow the user to modify the flight level and the speed information before submitting the "Try" or the "Apply" request.
The Reroute Preparation screen is described in an earlier section of this document.
This rerouting request will issue a query to the CFMU system.
If the rerouting fails to pass validation, the request is then considered as another evaluation process. Error messages will be displayed as described above in the Reroute Evaluation section.
Because a rerouting request may result in important modifications for the flight, a Rerouting Confirmation dialog will be presented to the Operator before the request is sent to the CFMU system.

This is a modal dialog box ! It means that when it is opened, no other function can be invoked.
This confirmation dialog box contains a summary of the rerouting request :

  • Identification of the unique flight to be rerouted (IOBD, IOBT, ARCID, ADEP, ADES).
  • Type of "Apply" (including automatic filing of flight plan or not).
  • Rerouting details (alternate route, Maximum Shift+Delay, associated network address).


If the AUTOMATIC filing was selected by using the Reroute Apply File option, no action is required from the user if the "Apply File" process is successful.
With the MANUAL filing was selected by using the Reroute Apply option, if the "Apply" process is successful, a new slot will be booked and the user will have to REFILE a new FPL via SITA or AFTN networks.
The user has two options to continue:

  • Choose the Confirm button to confirm the rerouting request.
  • Choose the Cancel button to cancel the rerouting request and come back to the window where the "Apply" was requested. The Operator may then possibly change some details and issue a new request.


Once the Confirm button is chosen, then the Rerouting Request will be either:

  • ACCEPTED. In this case the following "Booked Reroute" confirmation dialog is displayed.
  • REJECTED. This means that the "Apply" request is considered as a Reroute Evaluation request (i.e. "Try"). In this case the Rerouting window closes and the Alternate Routes display is reactivated and the evaluation results are displayed as described in the Reroute Evaluation section.

After a successful confirmation the "Booked Reroute" modal dialog box is displayed. In that case no other function can be invoked.
Contrary to the succesful Rerouting Evaluation results that are of an informative nature, the results of the Rerouting Request are the ones applied to the CFMU system.
The displayed details correspond to the newly calculated values based on the booking of the new flight plan :

  • The selected Standard Route identifier for the rerouting (Std Route).
  • The length of the new route in Nautical Miles (Route Length).
  • The Most Penalising Regulation, if any (Most Penal Reg).
  • The newly obtained Shift+Delay (might be absent if flight no more regulated) (S+Delay).
  • The new Take Off Time (Calculated TOT or Estimated TOT).
  • The new Estimated Elapsed Time (EET).
  • The complete flight plan details used in IFPS.
  • Any relevant warning message (IFPS message, Exceptional condition,...).


Following actions are possible on the Booked Reroute dialog box:

  • Clicking the Print button will produce a paper copy of the new flight details as they appear on the window.
  • Clicking the Export button will save the new flight plan details displayed on the screen into a file. A special dialog box will pop up to ask the file name to the user. The Booked Reroute dialog box is not closed immediately in order for the user to issue an additional print request.
  • Clicking the Close button without an initial print or export request will cause a confirmation dialog box to pop up : You have not printed/exported a copy of the new flight details. Do you want to PRINT/EXPORT it ?
  • After a print/export, the Close button will close automatically both the "Booked Reroute" dialog box and the "Alternate Routes" window.


The box containing the new flight plan details allows to Copy/Paste its content.