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Phonetic alphabet

Numbers

Numbers are normally spoken digit by digit — e.g. 120.375 is “WUN TOO ZE-RO DAY-SEE-MAL TREE SEV-en FIFE”. Round figures may be grouped, e.g. 3000 ft as “TREE TOUSAND”.

You don't talk in Morse, but you'll hear it: navigation aids (VOR, NDB, ILS) constantly transmit their identifier in Morse. Before using one, listen and confirm the ident matches the one on your chart — that proves you've tuned the right station and it's serviceable.

• Request radio checkConfirm your transmissions are readable (you'll get a readability 1–5).
• Request taxi / taxi informationTo taxi for departure — “taxi” at an ATC field, “taxi information” at an Air/Ground field.
• Request Basic / Traffic / Deconfliction ServiceTo receive that air traffic service (see above).
• Request MATZ penetrationTo cross a Military Aerodrome Traffic Zone (see below).
• Request zone transitTo cross a control zone / CTR.
• Request Special VFRA clearance to fly VFR in a control zone when conditions are below the normal VFR minima.
• Request joining instructionsHow to join the circuit at your destination.
• Request change to <station> <freq>To change to another frequency (a mandatory readback).
• Request climb / descent to <level>A level change (read back the level instruction).

Acknowledge a traffic call promptly with your sighting status. Under a Traffic Service you still take your own avoiding action.

• ▸You can't enter controlled airspace (a control zone or area) without a clearance. Call the controlling unit and request a zone transit, then pass your details when asked.
• ▸The clearance may be a Special VFR (SVFR) clearance — permission to fly in the zone, usually with a route and a level restriction.
• ▸Read back the clearance, the route and any level restriction — they are mandatory readbacks.
• ▸If you're not cleared, remain clear of the zone.

“… cleared to the zone boundary, route via Whiskey, Special VFR not above altitude 1500 feet” → readback: “Cleared to the zone boundary, route via Whiskey, Special VFR not above altitude 1500 feet, G-ABCD”

Select altitude reporting (Mode C) unless told otherwise; the ATC instruction for it is “squawk Altitude” (CAP 413 Table 2). A frequency-monitoring code (“listening squawk”) is a discrete code you set while just listening out on a unit's frequency, so they know you're monitoring without calling. Always read SSR instructions back, e.g. “squawk 6171” → “6171, G-ABCD”.

Flying close to certain controlled airspace without wanting a service? Set that airfield's published frequency monitoring code (with Mode C if you have it) and listen out on the promulgated frequency. The code tells ATC you're on frequency — so if you look like you're about to infringe, they can call you and sort it before it happens.

• It is not an air traffic service — the code and Mode C are unvalidated and unverified, and navigation stays your responsibility.
• You still need clearance to enter controlled airspace and permission for an ATZ, exactly as normal.
• Lost near one of these airfields? Ask the radar unit for help — or squawk 0030 and call London Centre on 121.500.

A selection, not the full list. Each code applies only in a specific area, and codes change — check the current charts and the aerodrome's own published information before you fly.

A VDF (VHF Direction Finder) station fixes your bearing from your transmission. Ask: “<station>, <callsign>, request QDM, <callsign>” — repeat your callsign at the end of a VDF call. For a QTE, prefix with “true bearing, true bearing”. Each bearing comes with an accuracy class (A is best, down to D).

These must be read back word-perfect. Other information (e.g. readability) is acknowledged, not read back.

• ▸Taxi and towing instructions
• ▸Level instructions
• ▸Heading instructions
• ▸Speed instructions
• ▸Airways or route clearances
• ▸Approach clearances
• ▸Runway-in-use
• ▸Clearance to enter, land on, take off on, backtrack, cross or hold short of any active runway
• ▸SSR (squawk) operating instructions
• ▸Altimeter settings — including the units when the value is below 1000 hectopascals
• ▸VDF information
• ▸Frequency changes
• ▸Type of ATS service
• ▸Transition levels

CAP 413 Edition 24, §2.69. A conditional clearance is read back with the condition FIRST and in the same sequence it was given — “behind the landing Cessna, line up runway two four, behind”. Read back complete and in order: an incomplete read-back is harder to spot than a wrong one.

TowerTalk's Virtual ATC pulls the latest METARs for you. You can also read them at aviationweather.gov, or get a UK aviation weather briefing from the Met Office.

EGSH 121350Z 25012KT 9999 FEW035 14/09 Q1013

• EGSHStation — the airfield's ICAO code (here, Norwich).
• 121350ZDate & time — 12th of the month at 1350 UTC. The Z (“Zulu”) means UTC, never local time.
• 25012KTWind — from 250° at 12 knots. “G” adds a gust (25012G24KT); “VRB” = variable; “00000KT” = calm.
• 9999Visibility — 9999 means 10 km or more. Smaller figures are metres (e.g. 4000 = 4 km). “CAVOK” = clear & good.
• FEW035Cloud — FEW (1–2 oktas) at 3,500 ft. SCT = scattered, BKN = broken, OVC = overcast.
• 14/09Temperature / dew point — 14°C, dew point 9°C. An “M” means minus (e.g. M02 = −2°C).
• Q1013QNH — 1013 hectopascals. Set this on your altimeter. (The US uses A2992 = inches of mercury.)

Weather is added when present: RA rain, SHRA showers, TS thunderstorm, BR mist, FG fog; “-” light, “+” heavy; NSC = no significant cloud, NOSIG = no significant change expected.

An ATIS (Automatic Terminal Information Service) is a continuous recorded broadcast of an aerodrome's essential information, on its own frequency, so it doesn't tie up the controller.

• ▸The information letter (Alfa, Bravo, Charlie…), changed at each update
• ▸Runway(s) in use
• ▸Surface wind
• ▸Visibility, weather and cloud
• ▸Temperature and dew point
• ▸QNH (and QFE where given)
• ▸Any operationally significant remarks

Listen before your first call. On contact, tell the unit you have the current letter — e.g. “… information Bravo”. If there's no ATIS, ask the station for the current aerodrome information.

UK airspace is divided into two Flight Information Regions (FIRs): the London FIR (south) and the Scottish FIR (north).

Within each, a Flight Information Service — London Information or Scottish Information — gives a Basic Service to en-route VFR traffic: flight information, weather, and traffic information where available. Free-call them and “request Basic Service”.

• ▸SAFETYCOM (135.480 MHz) is the common frequency for UK aerodromes that have NO notified air traffic service. There is no controller and no clearances.
• ▸Use it within 10 NM of the aerodrome. If the aerodrome has its own notified frequency, use that instead.
• ▸Identify the aerodrome by name suffixed “traffic”, e.g. “Sleap Traffic”. Keep transmissions correct and concise.
• ▸Make blind calls of your position and intentions so others can build a picture — you make all your own decisions.

Sleap Traffic, G-ABCD, overhead 2000 feet, descending dead side to join downwind runway 36, Sleap Traffic

Exact circuit calls vary by airfield and service. At a controlled (Tower) field, read back clearances; at an Air/Ground (“Radio”) field you give your position and intentions and make your own decisions.

The international aeronautical emergency frequency is 121.5 MHz (civil); military aircraft also guard 243.0 MHz (UHF). Address a MAYDAY or PAN to the unit you're already working, or to 121.5 MHz if you need to.

Order of priority

1. Distress messages (MAYDAY)
2. Urgency messages (PAN-PAN), including medical transports
3. Direction-finding messages
4. Flight safety messages
5. Meteorological messages
6. Flight regularity messages

The emergency frequency 121.500 is guarded continuously by the Distress & Diversion cell — military controllers at NATS Swanwick, callsign “London Centre” — with coverage over most of the UK above about 3,000 ft.

• In an emergency, call the unit you're already talking to first — they know where you are. Not in contact with anyone? Call on 121.5. You don't need to address any particular station: the D&D controller answers the MAYDAY or PAN PAN wherever it comes from.
• Squawk 7700 alongside the call so every radar unit in the area sees the emergency (7600 for radio failure).
• Lost, but not yet an emergency? Squawk 0030 and call London Centre on 121.5 for navigational help.
• In the UK, ending a transmission with “OUT” means the transmission has ended and no response is expected (CAP 413 Ed 24, Appendix 1: UK differences from ICAO).
• You can rehearse this for real: CAP 413 sets out a Practice PAN procedure for making a practice urgency call to D&D on 121.5 — check the current manual for the exact call before trying one, and expect to stand by if the frequency is busy with a real emergency.

Sources: CAP 413 Ed 24, CAA Safety Sense Leaflet 22 (Radiotelephony).

If the radio fails, keep flying the aircraft and squawk 7600 (or 7700 if it's part of a wider emergency). What you do next depends on which part has failed.

MAYDAY RELAY: if you hear a distress call the controlling station hasn't acknowledged, or you need to pass one on behalf of an aircraft that can't, transmit “MAYDAY RELAY” (×3) and relay the distress message you heard.

Unsure of your position? Don't leave it too late — ask for help early: request a position fix or a QDM, or call for a Basic/Traffic Service. If you become genuinely lost or short of options it becomes an urgency (PAN-PAN), or a distress (MAYDAY) if you're in real difficulty.

SRG1171 1.1 · 1.2 · 1.3 · 1.4 · 1.6 · 1.8

• ▸Nothing transmits until the set has power — on most light aircraft that means master switch, then avionics master, then the set itself. The exact order is aircraft-specific: follow the checklist for YOUR aircraft, not a generic one.
• ▸Most sets hold two frequencies: ACTIVE (what you're on) and STANDBY (what you'll use next). Tune the standby, check it, then swap. You can set up the next frequency long before you need it.
• ▸VOLUME sets how loud the receiver is. SQUELCH mutes the constant background hiss until a signal is strong enough to break through — open it briefly to prove the set is alive, then close it until the hiss just stops.
• ▸The audio panel (intercom / station-selection box) chooses which radio you HEAR and which you TRANSMIT on. Selecting a box to listen to is not the same as selecting it to transmit on — a classic cause of 'nobody can hear me'.
• ▸Silent radio? Check in order: power on → volume up → squelch set → correct box selected → correct frequency ACTIVE (not sitting in standby). Most 'failures' are one of these.
• ▸The aircraft's radio installation needs its own OFCOM licence, separate from your FRTOL — your licence covers the operator, that one covers the equipment.

SRG1171 3.2 · 3.4 · 3.6 · 3.9

• ▸Bigger aerodromes split the ground stations: you may work Delivery (clearance), then Ground (taxi), then Tower (take-off) — each handover is a normal frequency change, told to you by the controller.
• ▸Listen to the ATIS before first contact and quote its letter — it saves the controller passing the whole aerodrome picture to you.
• ▸A departure clearance is not a take-off clearance. It tells you what to expect after departure; only Tower clears you onto the runway and into the air.

SRG1171 3.3

• ▸A holding point is the last place to stop before the runway. Instructions to hold at, or hold short of, a point are mandatory readbacks.
• ▸Runway incursion — an aircraft, vehicle or person on a runway without clearance — is one of aviation's biggest ground risks, which is why runway-related instructions carry the strictest readback discipline.
• ▸Never cross a lit stop bar. If you are unsure of your position on the aerodrome, stop and tell the controller.

SRG1171 4.4

• ▸Controllers space circuit traffic three main ways: ORBIT (a 360° turn, usually stated left or right), EXTEND (continue a leg — usually downwind — until told or until a reference), and HOLD (stay at a stated position or point).
• ▸All three are instructions about where the aircraft goes, so acknowledge and comply — and if an instruction would put you somewhere unsafe, say unable and offer what you can do.

SRG1171 5.10

• ▸Danger Areas (EG D-numbers on the chart) contain activities hazardous to flight — live firing, fast jets, drops. Some are active only at published times.
• ▸Two radio services exist around them, and the difference matters: a DACS (Danger Area Crossing Service) can give you a CROSSING — the unit controls or coordinates the activity. A DAAIS (Danger Area Activity Information Service) can only tell you what it KNOWS about activity — it cannot clear you through, and crossing on DAAIS information alone is your decision and your risk.
• ▸Which service exists for which area, and on what frequency, is published in the UK AIP (ENR section) — check before flight, not on the day over the radio.

SRG1171 5.5

• ▸An Aerodrome Traffic Zone protects the immediate circuit. You need permission (ATC) or information (AFIS/AGCS) before entering during its hours of watch — the rules differ by the type of unit at the aerodrome.
• ▸At an ATC aerodrome you need a clearance to enter; with AFIS you need to have obtained information; with AGCS you make blind-style calls and integrate yourself. The station's callsign suffix (Tower / Information / Radio) tells you which regime you're in.
• ▸MATZ (military) penetration is a separate, well-drilled procedure — see the MATZ topic. Don't conflate the two: a MATZ crossing does not deal with the civil ATZ that may sit inside it.

SRG1171 6.9

• ▸You can rehearse emergency calls with Distress & Diversion on 121.5 without declaring a real emergency — that's the point of the practice procedures.
• ▸Always prefix such a call so nobody launches a real response, and be ready to be told the frequency is busy with real traffic.