AIM Text
Pilots, when calling a ground station, should begin with the name of the facility being called followed by the type of the facility being called as indicated in TBL 4-2-1.
TBL 4-2-1
Calling a Ground Station
| Facility | Call Sign |
| Airport UNICOM | “Shannon UNICOM” |
| FAA Flight Service Station | “Chicago Radio” |
| Airport Traffic Control Tower | “Augusta Tower” |
| Clearance Delivery Position (IFR) | “Dallas Clearance Delivery” |
| Ground Control Position in Tower | “Miami Ground” |
| Radar or Nonradar Approach Control Position | “Oklahoma City Approach” |
| Radar Departure Control Position | “St. Louis Departure” |
| FAA Air Route Traffic Control Center | “Washington Center” |
4-2-7. Phonetic Alphabet
The International Civil Aviation Organization (ICAO) phonetic alphabet is used by FAA personnel when communications conditions are such that the information cannot be readily received without their use. ATC facilities may also request pilots to use phonetic letter equivalents when aircraft with similar sounding identifications are receiving communications on the same frequency. Pilots should use the phonetic alphabet when identifying their aircraft during initial contact with air traffic control facilities. Additionally, use the phonetic equivalents for single letters and to spell out groups of letters or difficult words during adverse communications conditions. (See TBL 4-2-2.)
TBL 4-2-2
Phonetic Alphabet/Morse Code
| Character | Morse Code | Telephony | Phonic |
| A | ● — | Alfa | (AL-FAH) |
| B | — ● ● ● | Bravo | (BRAH-VOH) |
| C | — ● — ● | Charlie | (CHAR-LEE) or |
| D | — ● ● | Delta | (DELL-TAH) |
| E | ● | Echo | (ECK-OH) |
| F | ● ● — ● | Foxtrot | (FOKS-TROT) |
| G | — — ● | Golf | (GOLF) |
| H | ● ● ● ● | Hotel | (HOH-TEL) |
| I | ● ● | India | (IN-DEE-AH) |
| J | ● — — — | Juliett | (JEW-LEE-ETT) |
| K | — ● — | Kilo | (KEY-LOH) |
| L | ● — ● ● | Lima | (LEE-MAH) |
| M | — — | Mike | (MIKE) |
| N | — ● | November | (NO-VEM-BER) |
| O | — — — | Oscar | (OSS-CAH) |
| P | ● — — ● | Papa | (PAH-PAH) |
| Q | — — ● — | Quebec | (KEH-BECK) |
| R | ● — ● | Romeo | (ROW-ME-OH) |
| S | ● ● ● | Sierra | (SEE-AIR-RAH) |
| T | — | Tango | (TANG-GO) |
| U | ● ● — | Uniform | (YOU-NEE-FORM) or |
| V | ● ● ● — | Victor | (VIK-TAH) |
| W | ● — — | Whiskey | (WISS-KEY) |
| X | — ● ● — | Xray | (ECKS-RAY) |
| Y | — ● — — | Yankee | (YANG-KEY) |
| Z | — — ● ● | Zulu | (ZOO-LOO) |
| 1 | ● — — — — | One | (WUN) |
| 2 | ● ● — — — | Two | (TOO) |
| 3 | ● ● ● — — | Three | (TREE) |
| 4 | ● ● ● ● — | Four | (FOW-ER) |
| 5 | ● ● ● ● ● | Five | (FIFE) |
| 6 | — ● ● ● ● | Six | (SIX) |
| 7 | — — ● ● ● | Seven | (SEV-EN) |
| 8 | — — — ● ● | Eight | (AIT) |
| 9 | — — — — ● | Nine | (NIN-ER) |
| 0 | — — — — — | Zero | (ZEE-RO) |
4-2-8. Figures
- Figures 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.”
Source: FAA Aeronautical Information Manual · current edition · paragraph 4-2-6.
Research Notes
AIM 4-2-6 covers aircraft call signs — the standard ways pilots identify their aircraft on the radio.
U.S. registration prefix: "N" — pronounced "November" in international comms. In U.S. domestic operations, "N" is commonly dropped on the initial call once two-way comms are established (controllers may abbreviate to the last three characters).
Call sign formats:
- Civil aircraft: The full registration (e.g., N12345 → "November One-Two-Three-Four-Five"). After comms established, may shorten to last three (e.g., "Three-Four-Five").
- Civil aircraft with aircraft type: "Cessna One-Two-Three-Four-Five" — substitutes the manufacturer/model for the "November" prefix. Common for GA.
- Air carriers: Company name + flight number ("Alaska 187"). The company name takes the place of the registration.
- Military: Branch + tail number variant ("Army Six-Six-One-Two").
Shortening protocols: The controller may abbreviate your call sign after the initial exchange. You may shorten back to match. BUT: if another similar call sign is on the frequency, ATC will use full call signs to avoid confusion.
Same-call-sign confusion: If two N-numbers ending in the same three digits are on the same frequency, ATC will use the full call sign on both. Pay attention — accidentally responding to another aircraft's clearance is a common error.
Reference: AIM 4-2-6; FAA Order 7110.65 § 2-4 (Call signs).