Radio architecture click a component
Simplified — not for operational use. Click an RMP, a radio, the ATSU, the ACP, or SELCAL.
Click any component above to see what it does →
When a box goes quiet
REVERSIONARY PATHS
Every radio and panel here has a stand-in. If RMP 1 or 2 fails, RMP 3 on the pedestal can tune any VHF or HF radio in its place. If the ACP itself fails, each panel has a mechanical backup mode that hard-wires the radios straight to the headset, bypassing the electronics entirely. And because HF and SATCOM exist alongside VHF, losing line-of-sight VHF coverage over an ocean isn't a lost-comms event — it's a reason to switch to the long-range set that was there for exactly this.
Quick reference
RADIOS
- 3 VHF (voice, plus ACARS data usually on VHF3) and 2 HF (long-range/oceanic)
- VHF1 normally guards 121.5 MHz emergency frequency
- HF needs a tuned antenna coupler and degrades in precipitation static
CONTROL PANELS
- RMP1 (Capt) and RMP2 (F/O) each normally control their own radios
- RMP3, on the pedestal, is a standby that can take over either side
- ACP selects transmit radio and adjusts receive volume per source
DATALINK
- ATSU manages ACARS messages — clearances, weather, company reports
- Text appears on the MCDU and can print on the flight deck printer
- SELCAL lets crews leave HF/VHF volume down until their code is called