14-2-2

Abnormal Situations

JO 7110.65BB, Change 3, effective July 9, 2026 · Official text on faa.gov

When an Initial Contact (IC) mismatch or confirm assigned altitude (CAA) downlink time‐out indicator is displayed in the full data block (FDB) and ACL, the controller who has the aircraft on their voice frequency must use voice communication to verify the assigned altitude of the aircraft and acknowledge the IC mismatch/time‐out indicator.
Note

All sectors in the controlling ARTCC displaying an FDB will show the IC mismatch/time‐out indicator.
Abnormal CPDLC indications must be acknowledged by the controller only after required coordination has been performed.
Use voice communications when overriding an open CPDLC clearance and issuing alternate control instructions. If the CPDLC clearance contains multiple elements, the entire clearance must be restated.
Phraseology

DISREGARD CPDLC (type) CLEARANCE (description of clearance) AND SEND AN UNABLE (alternate clearance).

Example

“American Fifty‐Two, disregard CPDLC altitude clearance to flight level three five zero and send an unable. Climb and maintain flight level three one zero.”
“Delta Four Twenty‐Three, disregard CPDLC route clearance direct Memphis and send an unable. Cleared direct Nashville, direct Memphis, rest of route unchanged.”
“United Thirty‐Two, disregard CPDLC hold clearance at JKSON and send an unable. Cleared to Atlanta airport via direct JKSON GLAVN one, maintain flight level three three zero.”
“Alaska Ten, disregard CPDLC crossing and speed clearance at EMZOH and send an unable. Cross EMZOH at and maintain flight level two eight zero at two five zero knots.”

Note

Controllers should be aware that the CPDLC clearance being overridden may not have been received on the flight deck at the time of the voice communication. This phraseology tells the pilot exactly which clearance requires an UNABLE response.
Controllers may cancel an open uplink only after ensuring the pilot has been issued and acknowledged, via voice communication, the superseding ATC clearance.
Note
1. The provisions of this paragraph are not intended to replace the requirements to override a CPDLC clearance as stipulated in paragraph 14-2-3.
2. Canceling an uplink only removes the uplink from the CPDLC ground system. The uplink remains open on the flight deck. Controllers must instruct the pilot to respond with an unable to close the uplink on the flight deck.
3. The ability to cancel an uplink is only provided to allow controllers to clear open uplink indications in the FDB and ACL. Clearing these indications allows controllers to continue CPDLC operations with the affected aircraft.
For No Radio (NORDO) aircraft with an active CPDLC connection:
1. It is permissible for the sector with eligibility to mark the aircraft on frequency to allow CPDLC communications with that aircraft.
2. Use procedures in FAA Order JO 7110.65, paragraphs 5-2-4, Radio Failure, and 10-4-4, Communications Failure, for all CPDLC aircraft that experience a two‐way voice radio communications failure.