Section 12. Collaborative Trajectory Options Program (CTOP)


CTOP is a method of managing demand through constrained airspace leveraging the use of one or more FCAs while considering customer preference with regard to both route and delay as defined in a Trajectory Options Set (TOS). CTOP TMIs are managed through the Traffic Situation Display (TSD). The TOS will allow the customer to better manage flights by expressing route and delay preferences. Whereas a traditional flight plan contained a single request with a defined route, altitude, and speed, a TOS may contain multiple trajectory options with each one containing a different route, altitude, or speed. In addition to multiple options within a single TOS, each option may contain “start” and “end” times which they are willing to accept for that particular option. Each option will be ranked in the order of customer preference indicating their willingness to accept one option over another. This will be expressed in minutes of ground delay. Using algorithms comparing capacity and demand, the CTOP will look at each trajectory option and determine the amount of ground delay that would need to be associated with that option (which may be zero). CTOP will then assign the most preferred trajectory available. Customers must file flight plans in accordance with the TOS option assigned. Customers may manage their flights through the use of the TOS or through the substitution of flights.


CTOP may be applied to all aircraft departing airports in the contiguous United States and from select international airports. Aircraft that have been assigned an EDCT in a CTOP should not be subject to additional delay. Exceptions to this policy are miles-in-trail and departure/en route spacing initiatives that have been approved by the ATCSCC.

  1. CTOP - Collaborative Trajectory Options Program - A type of traffic management initiative which leverages one or more FCAs to identify demand. Then, based on customer preferred options (as specified in a TOS), it assigns either a route to avoid the FCA, or a route and EDCT to meet an allocated slot time within the FCA.
  2. TOS - Trajectory Options Set - A message sent by the NAS user to TFMS defining a group of preferences for how they would like to see a specific flight managed. These preferences are defined through a combination of routes and/or altitudes and/or speeds with each trajectory being weighted through the use of flight operator submitted preferences.

The ATCSCC must:

  1. In conjunction with the field facilities, identify the constraint through the use of FEA(s)/FCA(s).
  2. Conference affected facilities and system users as appropriate.
  3. Create the CTOP in the Traffic Situation Display.
  4. When time permits, send the Proposed CTOP with the advisory.
  5. Send the Actual CTOP with the advisory.
  6. Coordinate with affected facilities to ensure the CTOP is adequately managing demand.
  7. Revise CTOP parameters as necessary and send the Revised CTOP.
  8. Cancel the CTOP as per paragraph 18-12-8.

The ARTCC TMU must:

  1. Issue a GI message advising of the CTOP. In some instances, verbal notification, in addition to a GI, may enhance the dissemination of information.
  2. Monitor the effectiveness of the CTOP and notify the ATCSCC with requests for adjustments and/or revisions as necessary.
  3. Issue assigned route and EDCT information to non FDEP/FDIO-equipped towers and other customers in sufficient time for proper planning and control actions. This does not include non-FDEP towers that are satellites of TRACON facilities.
  4. Relay information, received from Terminal facilities, to the ATCSCC about EDCT issues (i.e., flights requiring a revision due to mechanical or flight crew duty issues).
  5. Ensure route compliance with assigned TOS option and issue route amendments as needed.
  6. Provide EDCT information, when requested, for flights departing underlying non-towered airports. If a flight departing a non-towered airport is airborne and not in compliance with a CTOP EDCT, coordinate with the ATCSCC for the appropriate course of action.


  1. Use the TSD/TSD-C to verify EDCT when missing or pilots advise they have something different.
  2. Ensure the EDCT is included in the flight clearance when a CTOP is in effect.
  3. Issue EDCT information to non-FDEP/FDIO-equipped towers.
  4. Provide EDCT information, when requested, for flights departing underlying non-towered airports.
  5. Forward EDCT issues to their overlying facility.
  6. Facilities with TMUs, assist the ARTCC to ensure route compliance.
  1. Field facilities with TSD may use the UPDATE EDCT feature to assign an EDCT.


Field facilities will only have the “unlimited” option available for use.

  1. Field facilities requesting a time other than the time assigned through the “unlimited” option must coordinate through the ATCSCC.
  2. Field facilities without the CTOP “UPDATE EDCT” feature must contact their overlying facility to request a new EDCT.
  3. The ATCSCC may amend EDCTs via the CTOP “UPDATE EDCT” feature by first attempting to utilize the “Unlimited” option, followed by the “Limited” option, followed by the “Manual” option.

When conditions no longer warrant a CTOP,

  1. The ATCSCC must:
  1. Conference facilities and customers as appropriate to develop an operational plan for exiting the CTOP.
  2. Cancel the CTOP and transmit an advisory stating the CTOP has been canceled.
  1. The ARTCC TMU and the terminal TMU must:
  1. Issue cancellation information to underlying facilities.
  2. Notify facility personnel, as appropriate, of the cancellation.

Facilities must use the NTML, where applicable, to document all pertinent information related to the CTOP. Facilities that do not have NTML will log information as required by local procedure.