Self-test

Self-test Subject 090 Communications

This self-test covers key concepts of Subject 090. Answers at the end.

VHF and radio discipline

1. Which frequency band does VHF aviation use?
2. Which modulation?
3. Which channel spacing is mandatory in EU since 2018?
4. What range at 1000 ft AGL?
5. What are the three core principles of radio discipline?

Alphabet and numbers

6. How is "DEMRA" spelled?
7. How is the digit 9 pronounced?
8. How is the frequency 118.450 spoken?
9. How is heading 90° spoken?

Standard expressions

10. What does "Roger" mean?
11. What does "Wilco" mean?
12. What does "Affirm" mean?
13. What is readability level 5?

Callsigns and transmissions

14. Which 5 components in the initial call?
15. When may the pilot abbreviate their callsign?
16. ATIS letter — what does the confirmation in the call mean?

Special situations

17. What are squawk codes 7700/7600/7500?
18. Which 9 components in a MAYDAY call?
19. Tower light signals on radio failure: steady green vs flashing green?
20. On interception: what does wing-rocking from the interceptor mean?

Transponder

21. What is the difference between Mode A and Mode C?
22. What is ADS-B?
23. When is Mode-C off requested?
24. VFR conspicuity code in Europe?

Special topics

25. What does QNH mean?
26. What is ATIS?
27. What is VOLMET?
28. EASA language proficiency level for PPL licence?

Answers

1. 118.000 – 137.000 MHz (VHF Aeronautical Mobile (R) Service).
2. AM (Amplitude Modulation), specifically A3E (Double-Sideband AM, voice).
3. 8.33 kHz channel spacing (EU Reg 1079/2012, since 5 February 2018).
4. About 39 NM (R ≈ 1.23 × √1000 = 39).
5. Brevity, Clarity, Accuracy.
6. Delta Echo Mike Romeo Alpha.
7. Niner (to distinguish from German "nein").
8. "One One Eight Decimal Four Five Zero".
9. "Zero Niner Zero" (three digits for heading).
10. "Received" — confirms only receipt, not understanding or action.
11. "Will Comply" — confirms receipt AND will obey.
12. "Yes" / "Confirmed" / "Correct".
13. "Perfectly readable" — like telephone.
14. Called station, own callsign, type (optional), position, intentions.
15. Only after ATC has abbreviated the callsign first.
16. ATC need not repeat the ATIS information (wind, QNH, runway).
17. 7700 = distress (emergency), 7600 = radio failure, 7500 = hijack.
18. MAYDAY × 3, callsign × 3, nature of distress, position, altitude, heading, intentions, POB, other info.
19. Steady green = cleared to land (in flight); flashing green = cleared to approach (return to pattern).
20. "You have been intercepted, follow me" — pilot should wing-rock back to confirm.
21. Mode A: code only (4 digits); Mode C: code + pressure altitude.
22. Automatic Dependent Surveillance — Broadcast: aircraft transmits GPS position, altitude etc. continuously.
23. On defective altitude encoder (transmits false altitude).
24. 7000 (Europe, ICAO standard) — in USA: 1200.
25. Altimeter setting so that the altimeter reads the field elevation AMSL on the ground.
26. Automatic Terminal Information Service — continuous recording with current weather, runway, QNH, NOTAMs at an aerodrome.
27. Meteorological Information for Aircraft in Flight — weather info for multiple fields, broadcast via HF or VHF.
28. Level 4 (Operational) minimum, re-test every 4 years.