Top regional ATC phraseology differences (FAA / UK CAA / EASA / TC)

Published 3 June 2026Reference article

Four regulatory frameworks define ATC phraseology for the airspace simmers fly: the FAA system in the US, the UK CAA CAP 413, the EASA SERA across the EU, and the Transport Canada AIM. They share an ICAO parent and converge on most of the important ground. They also diverge on a small number of specific points that matter every time a pilot crosses a frontier.

Below are eight of the most operationally significant differences for a simmer flying multi-region online networks. This is a selection; the book covers twenty-five with primary source citations.

1. Climb and descent verb

FAA

“Climb and maintain” / “descend and maintain”.

CAP 413, SERA, TC AIM

“Climb to” / “descend to”.

Mutually intelligible. Treated in detail in a separate article.

2. Altimeter unit

FAA

Inches of mercury (e.g., 29.92 inHg).

CAP 413, SERA

Hectopascals (e.g., 1013 hPa).

TC AIM

Inches of mercury (US-aligned).

29.92 inHg and 1013.25 hPa describe the same standard pressure. See the dedicated QNH article.

3. Transition altitude

FAA

Fixed at 18,000 ft MSL.

CAP 413

Variable, typically 3,000 to 6,000 ft; under multi-year harmonisation toward a single higher value.

SERA

Variable by state.

TC AIM

Fixed at 18,000 ft (US-aligned).

Detail and the UK harmonisation status in the transition altitude article.

4. QFE pressure setting

FAA, TC AIM

Not used.

CAP 413

Used; particularly in the visual circuit. Altimeter reads zero on the runway threshold.

SERA

On request only; largely historical.

A simmer who has only flown US procedures will not have encountered QFE. Setting QNH when the controller has issued QFE puts the altimeter reading off by the aerodrome elevation. The readback must include the “QNH” or “QFE” prefix to confirm which is in use.

5. Conditional line-up clearance

FAA

“Line up and wait” only. Conditional line-ups not used.

CAP 413, SERA, TC AIM

Conditional line-up authorised: “Behind the landing Airbus, line up behind”. Pilot reads back the conditional clearance and lines up only after the conditional aircraft has passed.

Failing to recognise a conditional line-up — and entering the runway before the conditional traffic has landed — is one of the most consequential phraseology errors on the radio. The full conditional must be read back, not just “line up and wait”.

6. LAHSO (Land and Hold Short Operations)

FAA, TC AIM

Used. The pilot may be cleared to land with a hold-short instruction relative to an intersecting runway.

CAP 413, SERA

Not implemented.

A pilot flying out of the US into the UK will not hear LAHSO again; a pilot flying from Europe into the US may encounter it for the first time. The pilot is always entitled to decline a LAHSO clearance and request a full-length landing instead.

7. Visual circuit terminology

FAA

“Traffic pattern”. Legs: upwind, crosswind, downwind, base, final.

CAP 413

“Visual circuit”. Same legs.

SERA, TC AIM

“Traffic circuit”. Same legs.

Same procedure, three different names. A controller hearing “in the pattern” in UK airspace will translate without effort; a pilot hearing “join right base in the visual circuit” in their first UK flight should not translate it as anything more complicated than “join right base”.

8. “Continue” on approach

FAA

Not used as a delaying instruction.

CAP 413, SERA, TC AIM

“Continue approach” means continue the approach but it is not a landing clearance. The pilot must still receive an explicit “cleared to land”.

This is one of the most safety-critical phraseology differences. A pilot hearing “continue approach” and treating it as a landing clearance has misread the instruction. Landing requires an explicit clearance.

Where the full set lives

The book covers twenty-five of these differences in a single side-by-side reference table, plus eighty-nine entries across all four frameworks organised by phase of flight. Every claim is cited to its primary source — FAA AIM, FAA Pilot/Controller Glossary, FAA Order JO 7110.65, CAP 413, SERA, or TC AIM.