AIM ¶ 4-2-7 — ICAO Phonetic Alphabet
AIM 4-2-7 explains the ICAO phonetic alphabet for pilot-ATC radio communications, including when to use it and the full A-Z and 0-9 pronunciation table.
AIM 4-2-7 establishes the ICAO phonetic alphabet as the standard way pilots and controllers spell out letters and numbers over the radio. Plain English letters can sound alike on a noisy frequency (B, D, E, P, T, V), so substituting unambiguous words like Bravo, Delta, Echo, Papa, Tango, Victor prevents costly misunderstandings.
The AIM directs pilots to use the phonetic alphabet in these situations:
- Initial contact with any ATC facility when stating your aircraft identification (e.g., "Cessna Six-One-Two-Tango-Charlie").
- Adverse communications conditions when single letters, groups of letters, or difficult words need to be spelled out.
- When ATC requests it because aircraft with similar-sounding call signs are on the same frequency.
Numbers also have standardized pronunciations — note "tree" for 3, "fife" for 5, "niner" for 9, and "zero" (never "oh"). These pronunciations reduce confusion with similar-sounding numerals, especially across languages and through static. While AIM 4-2-7 is a recommended practice rather than a regulation, fluent use of the phonetic alphabet is expected on every checkride and in everyday flying.