AIM ¶ 4-2-8 — Radio Number Pronunciation
Learn how to speak altitudes, airways, and frequencies over the radio per AIM 4-2-8. Examples for ceilings, jet routes, and decimals for pilot students.
In Plain English
AIM 4-2-8 standardizes how pilots say numbers on the radio so controllers and other aircraft can clearly understand altitudes, ceilings, winds, routes, and frequencies.
Key rules:
- Round hundreds/thousands up to 9,900 (ceilings, winds aloft): say them naturally. Example: 4,500 = "four thousand five hundred."
- Above 9,900: separate the digits before "thousand." Example: 13,500 = "one three thousand five hundred."
- Airways and jet routes: spoken as a name plus number group. Example: V12 = "Victor Twelve"; J533 = "J Five Thirty-Three."
- All other numbers: pronounce each digit individually. Example: 10 = "one zero."
- Frequencies with a decimal: say "POINT." Example: 122.1 = "one two two point one." Under ICAO procedures the decimal is spoken as "DECIMAL," and the FAA accepts that from military or ICAO-required aircraft.
Using these standard phrasings reduces readback errors and is a basic professionalism item examiners listen for during checkrides.
AIM Source Text
FAA AIM ¶ 4-2-8Figures indicating hundreds and thousands in round number, as for ceiling heights, and upper wind levels up to 9,900 must be spoken in accordance with the following. Numbers above 9,900 must be spoken by separating the digits preceding the word “thousand.” Transmit airway or jet route numbers as follows. All other numbers must be transmitted by pronouncing each digit. When a radio frequency contains a decimal point, the decimal point is spoken as “POINT.”
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You are flying VFR in Class E airspace at 8,500 feet MSL during the day. What are your minimum visibility and cloud clearance requirements?
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Oral Exam Questions a DPE Might Ask
Q1How do you state an altitude of 13,500 feet on the radio?
Per AIM 4-2-8, numbers above 9,900 are spoken by separating the digits before "thousand," so 13,500 is spoken as "one three thousand five hundred."
Q2How are airway and jet route numbers transmitted?
Per AIM 4-2-8, airway and jet route numbers are spoken with the route designator and number group — for example, V12 is "Victor Twelve" and J533 is "J Five Thirty-Three."
Q3How is the decimal point in a radio frequency such as 122.1 pronounced, and is there an ICAO difference?
Per AIM 4-2-8, the decimal is spoken as "POINT," so 122.1 is "one two two point one." ICAO procedures use "DECIMAL," and the FAA honors that usage by military aircraft and others required to use ICAO procedures.
Related Paragraphs in Chapter 4
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