FAA En Route Domestic CPDLC—Operational Background Information for Pilots

Updated: 4/17/2019

FAA has been operating in Indianapolis and Kansas City Centers part time since 3/25/2019.

FAA is planning on transitioning to full-time 24/7 operations at Kansas City Center on Wednesday 4/17/2019, and at Indianapolis Center on Monday 4/22/2019.

FAA is currently replanning the entire program, due to significant schedule delays caused by the partial government shutdown at the beginning of the year.  Implementation will likely stretch through 2020.

Note that pre-flight Departure Clearance services are unaffected by this change and are in full operation 24/7.

Update: In April 2019, FAA published additional detailed guidance on the use of CPDLC, available on the Harris website.

Note that this material does not supersede any company training, bulletins, or other official guidance, but does provide additional reference material for using CPDLC in En Route US Airspace.

Disclaimer: ALPA has developed this webpage for informational purposes only, and it is not intended to supersede any company training, guidance, or other material. In case of any conflict, company-provided information should be considered to have primacy. If you have any questions, please contact ALPA Engineering and Air Safety at EAS@alpa.org or 800-424-2470.


The Federal Aviation Administration (FAA) is in the process of deploying controller-pilot data link communications (CPDLC) in U.S. en route domestic airspace.

CPDLC allows air traffic controllers to send data link clearances and instructions to pilots in domestic airspace, including climbs, descents, reroutes, and handoffs between ATC sectors in the En Route Center (ARTCC) environment. In addition to flight efficiency benefits from streamlined communications, CPDLC is expected to enhance safety as reroutes are provided in a form that allows for loading directly into the FMS, reducing the risk of typing errors or fix name confusion.

For pilots with international or oceanic experience with CPDLC, the service is largely the same in domestic airspace. However, there are some areas, especially concerning LOGON, that are unique to the United States. Also, because the domestic en route environment is more tactical than the oceanic environment, pilots should expect to receive both CPDLC and voice communications routinely on all flights.

ALPA will keep this page up to date with the latest information for pilots as the system is deployed.

General Guidance

  1. If you do not understand or are not absolutely clear on the interpretation or application of a CPDLC clearance, do not accept it (select REJECT/UNABLE), and then verify by voice.
  2. Follow company training and procedures for use of CPDLC.
  3. Review the dispatch release and MEL to ensure that the aircraft is qualified to perform CPDLC.
  4. Respond to all CPDLC messages received, including those that only require an acknowledgement (ROGER/ACCEPT).
  5. All CPDLC messages will be normal operational ATC clearances, and CPDLC messages do not require voice readbacks unless requested by ATC (acknowledgement is through the ACCEPT/WILCO or REJECT/UNABLE response via CPDLC).
  6. Note that clearances given by voice by ATC still require voice readbacks.

En Route CPDLC Site Activation Map

The latest map showing the status of CPDLC deployment at each FAA Air Route Traffic Control Center is available online from Harris Corp.

En Route Deployment Schedule

The following is the latest map showing the start of 24-hour, 7 days per week en route services. We will keep this map up to date as there are schedule changes.

Dates for the start of 24/7 services (Expanded DFV)

NOTE: Limited services may be received earlier.

Part-time use of CPDLC has been in operation at Indianapolis and Kansas City ARTCCs since 3/25/2019, and has been proceeding on track.  Kansas City ARTCC will transition to 24/7 operations starting Wednesday 4/17/2019, and Indianapolis ARTCC will transition to 24/7 operations starting Monday 4/22/2019.

Note that the remainder of the deployment is being replanned due to impacts from the partial government shutdown, and will likely extend through 2020.

Once an ARTCC adjacent to Canada or Oceanic FIRs is activated, CPDLC handoffs will be provided from KUSA to the new FIRs.

Logon Procedures and Connection Issues

An active connection established with KUSA (Boeing implementation). Do not relogon if “ACT CTR” = KUSA
  • Flight crews should confirm on the ATC LOGON/STATUS page that you have an active connection with KUSA in level flight after departure and relogon to KUSA only if a connection does not exist.
  • Flight crews may (very occasionally) see a “NO COMM” or similar message while in flight; in this case, you should go to the ATC LOGON/STATUS page and see whether an active connection is still established with KUSA. If there is a connection, then no action is required. This indicates a temporary loss of radio link, but the connection remains alive.

Technical Background: If a relogon is attempted while a connection with KUSA is already established, the ground system can only assume that an avionics reset has occurred, and the connection must be completely torn down on both ends to ensure safety. This will require additional ATC action and voice confirmation, followed by a third logon to reestablish CPDLC. Therefore, flight crews should be careful to only log on if there is no active connection with KUSA.

Welcome Message

Once a connection is established with an ATC facility, the aircraft may receive a welcome message. Make sure you ACCEPT or ROGER this message (red arrow)

Controller Handoffs—Monitor and Contact

While originally planned for initial implementation, use of the “MONITOR [facility] ON [frequency]” handoff message (e.g., “MONITOR KANSAS CITY CENTER ON 123.875”) will be delayed for several months due to procedural issues uncovered during testing.

For the time being, all handoffs between ATC sectors will use CONTACT (e.g., “CONTACT KANSAS CITY CENTER ON 123.875”).

Per current voice procedures, CONTACT requires the pilot to check in on the new frequency via voice. Be sure to ACCEPT/ROGER the CONTACT message after tuning the VHF radio.

Loading Routes with SIDs and STARs

In general, receiving a route clearance revision via data comm will be loadable into the FMS with a button press (“autoload”). While this is of great convenience and enhances safety by eliminating typographic errors, there are two exceptions that pilots should be aware of:

  1. SIDs/DPs: Due to limitations in FAA ground systems, when receiving a clearance revision prior to departure, all standard instrument departures (SIDs)/departure procedures (DPs) need to be inserted manually by the pilot:

    Boeing-style implementation


    Airbus-style implementation (this example is split across pages 1 and 2)

  2. STARs/Arrivals: Due to limitations in FAA ground systems, procedure designs, and/or avionics limitations, SOME aircraft may not be able to load Standard Terminal Arrivals (STARs) or Arrivals when receiving a revision while en route. In these cases, pilots will need to manually insert the STAR. This is prompted by free text in the cockpit “MANUALLY LOAD ARRIVAL”:
    Boeing-style implementation

    Note that this does not apply to all aircraft; for example, B-737s are able to load STARs.

Pilot Use of Free Text or “Due to” Reasons

In general, you should not use FREE TEXT to respond to ATC, as this feature is not planned to be fully implemented on the ground side. If free text is sent, in most cases the ground system will return an error message, and the message is not delivered to the controller. The only exception is for the defined EMERGENCY pilot downlink messages.

Similarly, when using a “DUE TO” reason, do not select any options except for “DUE TO WX” or “DUE TO PERFORMANCE.” Do not use free text either. An error message will be returned in most cases.