Radio Communications

Study-aid disclaimer

Why radio work matters

Radio is how you share intentions, receive clearances and traffic information, and keep the National Airspace System orderly—especially near airports. A bad call is recoverable; a wrong assumption about what was cleared (takeoff vs LUAW, taxi vs cross the runway, Class D entry) is how runway incursions and midairs start.

ACS framing. Private Pilot Airplane ACS (FAA-S-ACS-6C) Area of Operation III, Task A expects knowledge, risk management, and skill with:

• Obtaining appropriate frequencies
• Proper radio procedures and ATC phraseology
• ATC light-signal recognition
• Appropriate transponder use
• Lost communication procedures and equipment causes
• Radar assistance (high level)
• NTSB reporting awareness (pointer)
• Runway Status Lighting Systems (pointer—not expanded here)

Risk management (ACS): communication workload, deciding if/when to declare an emergency, and avoiding non-standard phraseology that creates confusion.

Regulatory spine (high level):

Suggested internal links: [Airspace → /learn/airspace/] · [Navigation → /learn/navigation/] · [Emergency Procedures → /learn/emergency/] · [Night Flying → /learn/night-flying/] · [Pre-flight Planning → /learn/preflight/] · [Exam prep → /exam-prep/]

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Radio basics & call format

Listen first (AIM 4-2-2)

1. Listen before you transmit. Often ATIS or the frequency already has what you need. If someone else is talking, keying jams them.
2. After a frequency change, pause and clear the frequency before calling.
3. Think before keying; jot lengthy items.
4. Mic close to the lips; normal conversational tone; slight pause after keying so the first word is not clipped.
5. After release, wait a few seconds before calling again.
6. Stuck-mike awareness: unusual silence or continuous carrier—check volume, frequency, and that the mic is not keyed.
7. VHF is largely line-of-sight—altitude helps range.

Who / who / where / what (instructor memory aid)

A reliable initial-contact pattern for students:

1. Who you are calling (facility name + type)
2. Who you are (full call sign on initial contact)
3. Where you are (position on airport or in the air)
4. What you want (request / intentions), plus ATIS code when applicable

AIM 4-2-3 formalizes initial contact as: facility name; full aircraft identification; position when on the airport surface; type of message or short request.

Training-pattern example (ground):
“Midwest Ground, Cessna One Two Three Alpha Bravo, south ramp, ready to taxi VFR to the north, with information Golf.”

Training-pattern example (tower arrival):
“Midwest Tower, Cessna One Two Three Alpha Bravo, ten miles south, two thousand five hundred, inbound for landing with information Golf.”

Facility call signs (AIM 4-2-6)

Call signs (AIM 4-2-4)

• Civil: aircraft type/model/manufacturer name + registration digits/letters; drop the “N” when the type/name is stated (e.g., “Cessna One Two Three Alpha Bravo”).
• Use the full call sign on initial contact and whenever similar call signs are on frequency. ATC may abbreviate after contact is established; you may follow that abbreviation.
• If identity is doubtful: “Verify clearance for (your complete call sign).”
• Student pilots: AIM recommends identifying as a student on initial contact with ATC/FSS so controllers can give extra consideration—recommended technique, not a regulation.

Phonetics, numbers, altitudes (AIM 4-2-7 through 4-2-9)

Use ICAO phonetics for call-sign letters and when spelling is needed. Speak altitudes below FL180 as separate digits of thousands (and hundreds): e.g., 4,500 → “four thousand five hundred”; 12,000 → “one two thousand.” Frequencies: decimal as “point.”

Readbacks & acknowledgements (AIM 4-2-3, 4-3-18)

Acknowledge ATC callups and clearances with your aircraft identification and an appropriate reply (Wilco, Roger, Affirmative, Negative, or the clearance content).

Always read back (AIM 4-3-18):

• The runway assignment
• Any clearance to enter a specific runway
• Any instruction to hold short of a specific runway or to line up and wait

Controllers must request a readback of runway hold-short assignments if you omit it. Prefer reading back without being prompted—especially HOLD SHORT OF… and LAHSO (AIM 4-3-11).

Instructor point: “Roger” does not mean you will comply with a hold-short—read back the hold-short.

Compliance with ATC (14 CFR §91.123)

When ATC issues a clearance or instruction, you must not deviate except for an amended clearance, an emergency, or (as provided in the rule) in response to a traffic alert and collision avoidance system resolution advisory. If you deviate, notify ATC as soon as possible. If you are unclear, ask—AIM repeatedly prefers a clarifying question over a wrong assumption.

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Towered airports (ATIS, ground, tower, LUAW, hold short, readbacks)

Typical VFR flow (training sequence)

At many towered fields the student flow looks like:

1. ATIS (or AWOS/ASOS if that is what the airport uses) — copy code, runway, wind, altimeter, remarks
2. Ground (or clearance delivery where applicable) — taxi
3. Tower — takeoff / pattern / landing
4. After landing — remain on tower until instructed, then ground for taxi to parking (AIM 4-3-14 / 4-3-21)

Class B/C arrivals often involve Approach before Tower—details and equipment/comm requirements live on /learn/airspace/. AIM 4-3-2: maintain two-way radio contact with the tower while in Class B/C/D surface areas unless the tower authorizes otherwise; initial callup about 15 miles from the airport is the AIM good practice for towered airports.

ATIS (AIM 4-1-13)

ATIS is continuous recorded noncontrol information (weather, runway in use, approaches, NOTAM-type remarks, etc.) designed to cut frequency congestion. Listen before calling. On initial contact, state the ATIS phonetic code (e.g., “with information Golf”) so controllers can omit items that are current.

Do not say “have numbers” to mean you have ATIS. AIM: “have numbers” means wind, runway, and altimeter only—it does not indicate ATIS receipt.

Ground & taxi (AIM 4-3-14, 4-3-18)

• Contact ground / clearance delivery as appropriate before taxi. State identification, position, type of operation (VFR/IFR), and intentions.
• A clearance is required before taxiing on a runway, taking off, or landing while the tower is operating.
• ATC issues an explicit clearance for all runway crossings. Authorization to taxi to a runway is not authorization to enter or cross that runway.
• ATC will not use the word “cleared” for taxi authorizations (to avoid confusion with takeoff/landing clearances).
• Progressive taxi is available if you are unfamiliar or confused—ask.

Training-pattern taxi readback:
“Cessna Three Alpha Bravo, taxi Runway One Eight via Alpha, hold short Runway Two Seven.” →
“Cessna Three Alpha Bravo, runway One Eight via Alpha, hold short Runway Two Seven.”

Line up and wait vs cleared for takeoff (AIM 5-2-5)

If you LUAW and no takeoff clearance arrives in a reasonable time, contact ATC. Be especially vigilant at night, in reduced visibility, and with intersecting-runway operations—scan the full runway and final. If landing traffic is a factor, ATC will advise; never land on an occupied runway even if a landing clearance was issued—query and be ready to go around.

Training-pattern:
Tower: “Cessna Three Alpha Bravo, Runway One Eight, line up and wait.”
You: “Runway One Eight, line up and wait, Cessna Three Alpha Bravo.”
…later…
Tower: “Cessna Three Alpha Bravo, Runway One Eight, cleared for takeoff.”
You: “Cleared for takeoff Runway One Eight, Cessna Three Alpha Bravo.”

Hold short (including LAHSO pointer)

Hold short means stop short of the specified runway, taxiway, or point—do not cross the holding position markings. Read it back with the words HOLD SHORT OF….

LAHSO (Land and Hold Short Operations)—AIM 4-3-11: you may accept only if you can safely land and stop within the Available Landing Distance; student pilots / unfamiliar pilots should not participate; full readback including “HOLD SHORT OF…”. Decline if safety is in doubt. Deep LAHSO decision-making stays with your CFI and Chart Supplement ALD data.

Pattern / option (towered)

Traffic pattern components and left/right pattern expectations: AIM 4-3-2 / 4-3-3. “Cleared for the option” (AIM 4-3-23) allows touch-and-go, low approach, missed, stop-and-go, or full stop—at towers that approve it; tell ATC promptly if you will delay on the runway.

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Nontowered airports (CTAF, pattern, see-and-avoid)

CTAF & self-announce (AIM 4-1-9)

At airports without an operating control tower, communicate intentions and exchange traffic information via FSS (where applicable), UNICOM, or self-announce on the Common Traffic Advisory Frequency (CTAF). CTAF may be a UNICOM, MULTICOM, FSS, or (when the tower is closed) the tower frequency—published in the Chart Supplement and on charts.

Recommended advisory practices (AIM summary):

Where there is no tower, FSS, or UNICOM: self-announce on MULTICOM 122.9.

Critical AIM point: Pilots stating “Traffic in the area, please advise” is not a recognized self-announce phrase and should not be used under any condition. State your position and intentions instead so others can build a mental traffic picture.

Say the airport name at the beginning and end of self-announce transmissions (same UNICOM frequency may serve nearby fields). Use the runway number—do not say “active runway.”

Training-pattern CTAF inbound:
“Spencer traffic, Cessna One Two Three Alpha Bravo, ten miles southeast, two thousand five hundred, inbound for left downwind Runway One Four, Spencer.”

Training-pattern CTAF downwind:
“Spencer traffic, Cessna Three Alpha Bravo, left downwind Runway One Four, Spencer.”

Pattern direction & altitude (AIM 4-3-3, §91.126 pointer)

• Unless otherwise indicated, traffic-pattern turns are to the left (helicopters as applicable). Right traffic is charted (e.g., “RP” and runway numbers on sectionals) or shown by segmented-circle / pattern indicators (AIM 4-3-4).
• Recommended pattern altitudes (unless Chart Supplement publishes otherwise / cloud clearance requires otherwise): typically 1,000 ft AGL for propeller-driven aircraft; large/turbine not less than 1,500 ft AGL or 500 ft above the established pattern altitude.
• Standard pattern entry concepts (45° to downwind, etc.) are in AIM 4-3-3—fly them with your CFI; radio calls support the geometry, they do not replace it.

Straight-in (AIM 4-1-9): FAA discourages VFR straight-ins due to midair risk. If you choose one, self-announce ~8 to 10 miles out, coordinate with pattern traffic, and remember straight-in aircraft do not have priority over pattern traffic—comply with §91.113(g).

See-and-avoid still rules (14 CFR §91.113)

Radio calls are advisory at nontowered fields—there is no clearance to land from CTAF. Aircraft without radios, or pilots who do not announce, may be present. AIM: alertness and exchanging traffic information are essential; see-and-avoid and right-of-way rules remain mandatory. When two aircraft are approaching to land, the lower aircraft generally has the right-of-way, but must not cut in front of or overtake an aircraft on final (AIM 4-3-4 / §91.113).

Part-time towers: When the tower is closed, use CTAF self-announce (AIM 4-1-9). Confirm hours in the Chart Supplement / NOTAMs.

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Transponder codes (1200 / 7500 / 7600 / 7700)

Operate the transponder/ADS-B as AIM 4-1-20 and the regulations require for the airspace you are in (Mode C / ADS-B Out details → /learn/airspace/). Altitude reporting ON unless ATC says otherwise or equipment rules require otherwise.

Code-change caution (AIM 4-1-20): When switching codes, avoid momentarily selecting 7500 / 7600 / 7700 (and related discrete 76xx/77xx series that trip alarms). Example AIM guidance: changing 2700 → 7200, go via 2200—not through 7700.

Never operate a civil transponder on 7777 (military interceptor reserved).

ADS-B systems integrated with the transponder typically set emergency status when 7500/7600/7700 are entered; know your panel.

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Light gun signals

Used when radio contact cannot be established (or for non-radio aircraft). AIM 4-3-13; regulatory meanings in 14 CFR §91.125.

Aircraft meanings (verified AIM TBL 4-3-1 / §91.125)

AIM also lists meanings for vehicles/equipment/personnel (e.g., steady green = cleared to cross/proceed/go)—useful awareness; exam items usually focus on aircraft.

Acknowledgement (AIM 4-3-13 / 4-2-13)

• Day: acknowledge by moving ailerons or rudder (on ground) / rocking wings (in-flight lost-comm contexts as AIM describes).
• Night: blink landing or navigation lights.
• Between sunset and sunrise, to get the tower’s attention: turn on a landing light, taxi clear of the active runway into a position visible to the tower, and leave the light on until signals are received.

Limitations (AIM): You might not be looking at the tower when the signal is sent; light signals convey limited information (mainly approval/disapproval of anticipated actions) plus the general warning (alternating red/green).

In-flight exam focus: steady green = cleared to land; flashing green = return for landing; steady red = give way / continue circling; flashing red = airport unsafe / do not land; alternating red/green = extreme caution.

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Lost comm / emergency radio (high level)

Deeper emergency checklists, MAYDAY/PAN-PAN structure, and abnormal procedures: Emergency Procedures → /learn/emergency/.

Radio failure at a towered airport (AIM 4-2-13 — VFR framing)

Receiver inoperative (you can transmit): Remain outside or above the Class D surface area until traffic direction/flow is determined; advise the tower of type, position, altitude, intention to land, and request light-signal control; about 3–5 miles out, advise position and join the pattern; watch for light signals; transmit position as able.

Transmitter inoperative (you can receive): Remain outside/above Class D until flow is determined; join the pattern; monitor local control; watch for light signals; acknowledge as above.

Both inoperative: Remain outside/above until flow is known; join the pattern; maintain visual contact with the tower for light signals; acknowledge.

Before leaving the parking area: Prefer repair; if departure without radio is necessary, telephone the tower for authorization and instructions.

Squawk for lost radio / emergency

• Radio failure → 7600 (AIM 6-4-2)
• Distress / urgency needing radar alert → 7700 (AIM 6-2-2), and establish communications as soon as possible
• Unlawful interference → 7500 only (AIM Ch. 6)

You may not be in radar coverage—continue the appropriate code and use light signals / telephone / other frequencies as the situation allows.

Declaring an emergency (pointer)

If you need priority handling, say so early and clearly (MAYDAY / PAN-PAN patterns are taught with your CFI and covered on the emergency page). §91.3 authority and §91.123 deviation notification still matter—communicate when able.

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Tie-ins: airspace, navigation, emergency

High-level CFR pointers (do not substitute for the airspace page): §91.126 (Class G airports / traffic patterns), §91.127 (Class E), §91.129 (Class D), §91.130 (Class C), §91.131 (Class B)—each carries communications and operating expectations you must know for the knowledge and practical tests.

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Common pitfalls

1. Taking LUAW as takeoff clearance — wait for “cleared for takeoff.”
2. Not reading back hold-short / LUAW / runway — AIM expects those readbacks.
3. Crossing a runway without an explicit crossing clearance — taxi-to is not cross.
4. Blocking the frequency — failing to listen; stepping on others; stuck mic.
5. “Traffic in the area, please advise” on CTAF — AIM says do not use it.
6. Assuming CTAF is a clearance — nontowered is see-and-avoid + self-announce.
7. Wrong airport name / wrong runway on shared UNICOM frequencies.
8. Saying “have numbers” instead of the ATIS code.
9. Accidentally spinning through 7500/7600/7700 when changing squawks.
10. Head-down radio work in the pattern — fly first; brief calls; look outside (§91.113).
11. Similar call signs — use full ID; verify the clearance is for you.
12. Leaving tower frequency inside Class D without authorization / good reason (AIM 4-3-2 practices).

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FAQ

Q: Do I have to use exact AIM phraseology word-for-word?
A: Use standard AIM / Pilot/Controller Glossary phraseology. AIM 4-2-1: understanding is the goal; if concise glossary wording is not enough, use the words needed to be understood. Training examples on this page are patterns, not scripts.

Q: What is the difference between UNICOM and CTAF?
A: UNICOM is a nongovernment advisory station. CTAF is the frequency designated for airport advisory practices when the tower is not operating—it may be the UNICOM frequency, MULTICOM, FSS, or closed-tower frequency (AIM 4-1-9).

Q: When do I switch from ground to tower?
A: When ready to request takeoff (or as instructed). Remain on ground during taxi/runup unless advised otherwise (AIM 4-3-14). After landing, stay on tower until directed to ground (AIM 4-3-14 / 4-3-21).

Q: Steady red light gun in flight—what do I do?
A: Give way to other aircraft and continue circling (AIM 4-3-13 / §91.125). Wait for steady green to land.

Q: Should student pilots say “student pilot” on the radio?
A: AIM 4-2-4 recommends it on initial contact so ATC can provide extra assistance. Good practice in busy terminal areas; follow your CFI’s local preference.

Q: Is 1200 required everywhere for VFR?
A: Unless ATC instructs otherwise, VFR aircraft squawk 1200 with altitude reporting as applicable (AIM 4-1-20). When receiving radar services you will often be assigned a discrete code—return to 1200 when appropriate/instructed.

Q: Where do full emergency radio procedures live?
A: /learn/emergency/—this page only covers high-level lost-comm and squawk/light-gun hooks.

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Practice questions

1. AIM initial contact should include which elements?

Show answer

Facility name; full aircraft ID; position if on the airport surface; short request/message type (AIM 4-2-3).

2. “Line up and wait” authorizes takeoff. True or false?

Show answer

**False** — LUAW is not takeoff clearance (AIM 5-2-5).

3. On CTAF, is “Traffic in the area, please advise” an approved AIM self-announce phrase?

Show answer

**No** — AIM 4-1-9 says it should not be used.

4. Squawk code for two-way radio failure?

Show answer

**7600** (AIM 6-4-2).

5. Light gun, aircraft in flight, flashing red means?

Show answer

Airport unsafe—do not land (AIM 4-3-13 / §91.125).

6. Name three items AIM says pilots should always read back during taxi.

Show answer

Runway assignment; any clearance to enter a runway; any hold-short or LUAW instruction (AIM 4-3-18).

7. Primary see-and-avoid regulation citation?

Show answer

**14 CFR §91.113**.

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