Communications (VFR and IFR)
Phraseology
Use standard ICAO phraseology and the phonetic alphabet. Read back runway instructions, hold-short, altitude, heading, frequency and squawk. "Roger" acknowledges but is not a readback; "Wilco" means will comply.
Distress and urgency
MAYDAY three times for grave and imminent danger; PAN PAN three times for urgency without immediate danger. Emergency frequency is 121.5 MHz. Transponder codes: 7700 emergency, 7600 radio failure, 7500 unlawful interference.
Clearances
An IFR clearance normally contains the clearance limit, route, level and any speed or departure instruction. CPDLC and SELCAL reduce HF and VHF workload on long sectors.
Worked example
ATC: "ABC123, cleared to the XYZ VOR via A1, maintain FL100, squawk 4521." Correct readback: "Cleared to the XYZ VOR via A1, maintain FL100, squawk 4521, ABC123." For "line up and wait runway 27", read back "Line up and wait runway 27, ABC123".
Traps
Using "roger" for a clearance that requires a full readback; failing to read back a hold-short instruction; transmitting before checking the frequency; forgetting 7600 after a radio failure.