AIM ¶ 4-2-4 — Aircraft Call Signs

4-2-4. 4-2-4. Aircraft Call Signs Precautions in the Use of Call Signs. Improper use of call signs can result in pilots executing a clearance intended for another aircraft. Call signs should never be abbreviated on an initial contact or at any time when other aircraft call signs have similar numbers/sounds or identical letters/number; e.g., Cessna 6132F, Cessna 1622F, Baron 123F, Cherokee 7732F, etc. EXAMPLE- Assume that a controller issues an approach clearance to an aircraft at the bottom of a holding stack and an aircraft with a similar call sign (at the top of the stack) acknowledges the clearance with the last two or three numbers of the aircraft's call sign. If the aircraft at the bottom of the stack did not hear the clearance and intervene, flight safety would be affected, and there would be no reason for either the controller or pilot to suspect that anything is wrong. This kind of “human factors” error can strike swiftly and is extremely difficult to rectify. Pilots, therefore, must be certain that aircraft identification is complete and clearly identified before taking action on an ATC clearance. ATC specialists will not abbreviate call signs of air carrier or other civil aircraft having authorized call signs. ATC specialists may initiate abbreviated call signs of other aircraft by using the prefix and the last three digits/letters of the aircraft identification after communications are established. The pilot may use the abbreviated call sign in subsequent contacts with the ATC specialist. When aware of similar/identical call signs, ATC specialists will take action to minimize errors by emphasizing certain numbers/letters, by repeating the entire call sign, by repeating the prefix, or by asking pilots to use a different call sign temporarily. Pilots should use the phrase “VERIFY CLEARANCE FOR (your complete call sign)” if doubt exists concerning proper identity. Civil aircraft pilots should state the aircraft type, model or manufacturer's name, followed by the digits/letters of the registration number. When the aircraft manufacturer's name or model is stated, the prefix “N” is dropped; e.g., Aztec Two Four Six Four Alpha. EXAMPLE- Bonanza Six Five Five Golf. Breezy Six One Three Romeo Experimental (omit “Experimental” after initial contact). Air Taxi or other commercial operators not having FAA authorized call signs should prefix their normal identification with the phonetic word “Tango.” EXAMPLE- Tango Aztec Two Four Six Four Alpha. Air carriers and commuter air carriers having FAA authorized call signs should identify themselves by stating the complete call sign (using group form for the numbers) and the word “super” or “heavy” if appropriate. EXAMPLE- United Twenty-Five Heavy. Midwest Commuter Seven Eleven. Military aircraft use a variety of systems including serial numbers, word call signs, and combinations of letters/numbers. Examples include Army Copter 48931; Air Force 61782; REACH 31792; Pat 157; Air Evac 17652; Navy Golf Alfa Kilo 21; Marine 4 Charlie 36, etc. Air Ambulance Flights. Because of the priority afforded air ambulance flights in the ATC system, extreme discretion is necessary when using the term “MEDEVAC.” It is only intended for those missions of an urgent medical nature and to be utilized only for that portion of the flight requiring priority handling. It is important for ATC to be aware of a flight's MEDEVAC status, and it is the pilot's responsibility to ensure that this information is provided to ATC. To receive priority handling from ATC, the pilot must verbally identify the flight in radio transmissions by stating “MEDEVAC” followed by the FAA authorized call sign (ICAO 3LD, US Special, or local) or the aircraft civil “N” registration numbers/letters. EXAMPLE- If the aircraft identification of the flight indicates DAL51, the pilot states “MEDEVAC Delta Fifty One.” If the aircraft identification of the flight indicates MDSTR1, the pilot states “MEDEVAC Medstar One.” If the aircraft identification of the flight indicates N123G or LN123G, the pilot states “MEDEVAC One Two Three Golf”. If requested by the pilot, ATC will provide additional assistance (e.g., landline notifications) to expedite ground handling of patients, vital organs, or urgently needed medical materials. When possible make these requests to ATC via methods other than through ATC radio frequencies. MEDEVAC flights may include: Civilian air ambulance flights responding to medical emergencies (e.g., first call to an accident scene, carrying patients, organ donors, organs, or other urgently needed lifesaving medical material). Air carrier and air taxi flights responding to medical emergencies. The nature of these medical emergency flights usually concerns the transportation of urgently needed lifesaving medical materials or vital organs, but can include inflight medical emergencies. It is imperative that the company/pilot determine, by the nature/urgency of the specific medical cargo, if priority ATC assistance is required. When filing a flight plan, pilots may include “L” for MEDEVAC with the aircraft registration letters/digits and/or include “MEDEVAC” in Item 11 (Remarks) of the flight plan or Item 18 (OtherInformation) of an international flight plan. However, ATC will only use these flight plan entries for informational purposes or as a visual indicator. ATC will only provide priority handling when the pilot verbally identifies the “MEDEVAC” status of the flight as described in subparagraph b1 above. NOTE- Civilian air ambulance aircraft operating VFR and without a filed flight plan are eligible for priority handling in accordance with subparagraph b1 above. ATC will also provide priority handling to HOSP and AIR EVAC flights when verbally requested. These aircraft may file “HOSP” or “AIR EVAC” in either Item 11 (Remarks) of the flight plan or Item 18 of an international flight plan. For aircraft identification in radio transmissions, civilian pilots will use normal call signs when filing “HOSP” and military pilots will use the “EVAC” call sign. Student Pilots Radio Identification. The FAA desires to help student pilots in acquiring sufficient practical experience in the environment in which they will be required to operate. To receive additional assistance while operating in areas of concentrated air traffic, student pilots need only identify themselves as a student pilot during their initial call to an FAA radio facility. EXAMPLE- Dayton tower, Fleetwing One Two Three Four, student pilot. This special identification will alert FAA ATC personnel and enable them to provide student pilots with such extra assistance and consideration as they may need. It is recommended that student pilots identify themselves as such, on initial contact with each clearance delivery prior to taxiing, ground control, tower, approach and departure control frequency, or FSS contact.