Note When Selective Calling (SELCAL) equipment is used certain of the following procedures are superseded by those contained in 5.2.4.
5.2.1.1 Voice and CPDLC Response Rules
PANS. When a controller or pilot communicates via voice, the response should be via voice. Except as provided by 8.2.12.1, when a controller or pilot communicates via CPDLC, the response should be via CPDLC.
Training reference only. Always defer to current approved manuals and official procedures.
8.2.12.1 CPDLC Emergency Acknowledgment
PANS. When a CPDLC emergency message is received, the controller shall acknowledge receipt of the message by the most efficient means available.