Communications
This domain tests standard radiotelephony, readback discipline, frequency management and ATS data link. Expect questions that pick the correct phraseology for a situation, identify a missing readback, or ask what to do when a data link or frequency fails.
Standard phraseology
- Use Doc 9432 wording: "cleared", "line up", "hold short", "report", "say again", "standby", "roger", "affirm", "negative", "wilco", "unable".
- "Roger" means the message was received; it is not an answer to a question and never substitutes for a readback.
- "Take-off" is used only when issuing or cancelling an actual take-off clearance. In all other situations say "departure".
- Numbers are spoken digit by digit with standard pronunciations: tree, fife, niner; altitudes as "flight level tree fife zero" or "two thousand fife hundred".
Readback
Safety-related items must be read back: clearances and instructions, levels, headings, speeds, runway-in-use, hold-short instructions, altimeter settings, frequencies and SSR codes. Conditional clearances must be read back in full including the condition.
Frequency management
- VHF air-ground band 118.000–136.975 MHz, with 25 kHz or 8.33 kHz channel spacing depending on the State.
- Emergency frequency 121.5 MHz (243 MHz military) is monitored where required; guard transmitters used for triangulation.
- SELCAL alerts an aircraft without voice contact; transfer of communication is completed only when the next unit is contacted.
Data link
- CPDLC replaces voice for many clearances; ADS-C reports position automatically. Messages carry timestamps, and a clearance is not effective until the appropriate uplink response (WILCO/UNABLE) is received.
- On data link failure, revert to voice and advise the aircraft; do not assume a message left in the system was seen.
Worked example
Aircraft MD-123 on final, another on short final. Correct conditional clearance: "MD-123, behind the landing A320, line up runway 27 behind, report lined up." Reasoning: it names the traffic to follow, includes the runway, repeats "behind", and requires a report, making the condition verifiable.
Traps
Accepting "roger" for a clearance; using "take-off" outside a take-off clearance; issuing a conditional clearance without the traffic to follow; assuming a CPDLC uplink was read without a response.