RADIO MANAGEMENT, AUDIO PATHS AND INTERCOMMUNICATION
Radio management separates tuning from audio integration. The RMP establishes frequency/receiver selections; the audio-control path establishes what the crew hears and which transmitter is keyed. A correctly displayed active frequency does not prove that the intended receiver is being monitored at the required level, and hearing a frequency does not establish that the microphone will transmit on it. Keep active/standby transfer, receive selection, transmit selection and microphone/headset path as distinct observations. [92, PDF pp. 3–8]
The aircraft’s tuning architecture permits reconfiguration when the normal management path is unavailable. The historical briefing distinguishes automatic tuning, crew manual tuning through the FMGS and backup radio-navigation tuning through the appropriate RMP function. These modes have different authority and side-specific effects. A backup navigation selection should not be treated as an innocuous communication-frequency change. Establish the actual receiver/control source and applicable procedure before using it, then verify received identification and guidance rather than relying only on the tuning digits. [87, PDF pp. 206–211] [92, PDF pp. 5–7]
Flight interphone, service interphone, cabin calls and passenger address serve different recipients. Cabin communication can therefore fail or be misconfigured while external radio communication remains available. SELCAL identifies a selective call rather than providing speech or proving the whole audio path is correctly selected. Fenix’s supported Virtual Purser/airline-pack features use a configured cabin workflow; they should not be equated with every physical cabin interphone circuit. The current register also identifies different ACP presentation options on the named platform. [92, PDF pp. 4, 8] [81, Virtual Purser; Cockpit Cabin Call] [70, Available Options: fnx_acp_type]
ACARS and CPDLC add message channels with their own addressing, logon, reception and acknowledgement workflow. They are not replacements for audio selection or proof of an ATC clearance merely because a message reached the aircraft. Company information, load reports and ATC instructions have different authority and uses. For system troubleshooting, identify the service, chosen radio/data path, message status and intended recipient. The operational workflow chapter gives the supported Fenix steps; this architecture chapter avoids inventing a physical SATCOM/HF capability from a visible antenna or inactive control. [93, ACARS Overview; supported company-message functions] [94, How to CPDLC; supported logon/message workflow] [92, Communications contents/effectivity, optional systems] [95, PDF pp. 2–8]