ZLA Logo
Table of Contents

Radio and Interphone Communications — Phonetics and Numbers Last updated: 2017-07-10


To eliminate some ambiguity, each letter of the alphabet is associated with a word. These words are used whenever you pronounce letters on the radio. The 7110.65 has a complete list of the phonetic pronunciations in chapter 2, section 4. You will use these phonetic pronunciations regularly.


Altitudes are grouped into thousands and hundreds of feet. The word “feet” is omitted when referencing altitudes on the radio. For example:

  • 5000' would be spoken as “five thousand.”
  • 15000' would be spoken as “one five thousand.”
  • Altitudes may be restated in group form for emphasis. For example, you could say “maintain one one thousand, eleven thousand.”

Flight levels

Altitude assignments at or above 18,000' MSL are called “flight levels.” They are called “flight levels” because the pilot uses a constant altimeter setting and does not reference local altimeter settings until he descends back below 18,000'. When referencing flight levels, first state the term “flight level” followed by each digit of a flight level spoken individually. For example:

  • “Flight level two zero zero.”
  • “Flight level three four zero.”


Time always references zulu time (sometimes known as UTC Coordinated Universal Time or GMT Greenwich Mean Time), which is a standard time used around the world. VRC or ASRC will calculate this time for you (presuming that your computer system time and time zone is set correctly), and display it at the top of the screen.

When referencing time on the radio, always speak it as four digits. For example:

  • “Time one seven four five.”
  • “Time two three five nine.”

You may choose to add quarter minutes to the above if desirable. For example:

  • “Time zero four one two and one-quarter.”
  • “Time one one zero two and one-half.”
  • “Time two two five two and three-quarters.”

Altimeter setting

Altimeter settings are always issued in inches of mercury. When advising a pilot of the altimeter setting, use four digits and omit the decimal point. For example, an altimeter setting of 30.27” of mercury would be spoken, “Altimeter three zero two seven.”

Surface wind

Wind direction is always issued in degrees from magnetic north, and velocity in knots. The direction is always given in three digits and the velocity in the number of digits required. Pronounce each number individually, and omit the reference to “degrees” and “knots.” For example:

  • A wind of 70° at 20 knots would be spoken, “Wind zero seven zero at two zero.”
  • A wind of 340° at 5 knots would be spoken, “Wind three four zero at five.”


Aircraft headings are issued in reference to magnetic north. When assigning an aircraft a heading, it is issued using three digits spoken individually. For example:

  • A heading of 360 degrees would be spoken, “heading three six zero.”
  • A heading of 30 degrees would be spoken, “heading zero three zero.”
  • A heading of 5 degrees would be spoken, “heading zero zero five.”

Transponder codes

When issuing a transponder code always speak each digit individually. For example:

  • “Squawk Zero Four One Five”
  • “Squawk Seven Two One Zero”


When issuing a frequency, each digit is spoken individually. Zeroes beyond the first decimal place and all digits beyond two decimal places are not spoken. The word “point” is used for the decimal point. For example:

  • 135.000 MHz would be spoken, “One Three Five point Zero.”
  • 124.500 MHz would be spoken, “One Two Four point Five.”
  • 120.950 MHz would be spoken, “One Two Zero point Niner Five.”
  • 134.375 MHz would be spoken, “One Three Four point Three Seven.”


Each digit of an airspeed is spoken individually. Each digit of a mach number is spoken individually, and the word “point” is used for the decimal point. For example:

  • 250 Knots would be spoken “Two Five Zero knots.”
  • Mach .8 would be spoken “Mach point eight.”
  • Mach 1.2 would be spoken “Mach one point two.”
  • Mach .75 would be spoken “Mach point seven five.”


Distances are always given in nautical miles. State each digit of a distance followed by the word “mile.”

{Reference: FAAO 7110.65 2-4-16 through 2-4-18}