NATS ATC Knowledge Test: What to Study (Our Suggestions, 2026)

NATS says candidates who pass Stage 2 and meet the minimum requirements are invited to Stage 3, a virtual assessment centre with an interview, an “Air Traffic Control knowledge test” and an observed retest. Stage 4 adds a practical exercise and “ATC Knowledge Test part 2.” The natural question is what to revise, and the pages we read do not answer it: there is no syllabus, no sample question and no pass mark. So we cannot tell you what NATS will ask. What we can offer is our own suggestion: the aviation fundamentals set out in the Civil Aviation Authority’s public manuals, which are a sound grounding in the vocabulary of air traffic control whatever the tests turn out to cover.

ProSyllabus is an independent study site, not part of NATS or the Civil Aviation Authority. Facts about NATS come from its careers page, read on 28 October 2026, and its own news items listed under Sources; aviation facts come from the documents listed there. Our own advice is marked as ours.

NATS, Training to be an Air Traffic Controller, read 28 Oct 2026.

Two things follow. First, anything sold or shared as “the NATS knowledge test syllabus” cannot be checked against anything NATS has published, however confident it sounds; our list below is our own suggestion. Second, NATS also says applicants need no prior aviation knowledge, and its Level 5 apprenticeship teaches the job from the start. Our reading, which is ours and not NATS’s, is that knowing the vocabulary of air traffic control (what the airspace classes mean, how altimeters are set, how a METAR reads, how a controller speaks on the radio) can help with any question built on it. We cannot say whether the tests ask about these topics, and the study takes time, so weigh it against practising for the rest of Stage 3.

The table below is our choice of topics. Each aviation topic is set out in a public CAA document, so what you learn can be checked against the source rather than taken on trust; the last row comes from NATS’s own careers page.

UK airspace is split into two Flight Information Regions; below FL245 is the FIR and at and above FL245 the Upper Flight Information Region (CAP 493). Within them, the class of airspace decides the flight rules and the minimum service. CAP 493 lists the classes established in the UK FIRs as A, C, D, E and G, and calls A, C, D and E controlled airspace. Class A is for flights under Instrument Flight Rules (IFR) only, and ATC separates all aircraft. Classes C and D allow Visual Flight Rules (VFR) flights too, with a clearance; in C, VFR flights are separated from IFR flights, in D they are given traffic information instead. Class E is the one that trips people up: it is controlled airspace, yet a VFR flight needs no clearance to enter it. Class F, CAP 493 notes, is not currently established in the UK FIRs.

The structures sit on top of the classes. The CAA’s Skyway Code describes control zones round aerodromes as normally Class D, terminal manoeuvring areas such as London’s and Manchester’s as normally Class A, and airways as normally Class A, with some Scottish airways in Class E.

CAP 493 says a correctly calibrated altimeter set to QNH reads altitude, height above mean sea level; set to QFE it reads height above the aerodrome or other datum. Flight levels are referenced to the standard setting of 1013.25 hPa, so levels flown on it compare directly; CAP 493 spaces consecutive IFR cruising levels at pressure intervals corresponding to 1,000 ft in the standard atmosphere up to FL410. It gives the default transition altitude at civil aerodromes as 3,000 ft “unless otherwise notified,” defines the transition level as the lowest flight level available above it, at least a nominal 1,000 ft higher, and the transition layer as the space between them. It also says QNH and QFE are rounded down to the whole hectopascal before they are passed to a pilot, unless the pilot asks for the nearest tenth.

A METAR is a report of the weather actually observed; a TAF is a forecast. Both are written in a compact code; our suggestion is to learn it group by group. In a group such as 24015G27KT, the wind is from 240 degrees true at a mean of 15 knots, with a maximum of 27; 9999 means a visibility of 10 km or more; FEW, SCT, BKN and OVC give cloud amounts in eighths of the sky; and Q1012 is a QNH of 1012 hectopascals. CAP 493 adds a point that catches people out: meteorological reports give wind direction in degrees true, while the surface wind ATC passes to a landing aircraft is in degrees magnetic. Runway numbers are magnetic too: the CAA’s visual aids handbook describes a paved runway’s two-digit designation marking as its magnetic heading to the nearest 10 degrees. The two ends point 180 degrees apart, so they are normally numbered 18 apart, such as 09 and 27.

CAP 413 is the CAA’s radiotelephony manual, and its early chapters cover the basics: the phonetic alphabet (Alpha to Zulu, with the spellings Alpha, Juliett and Whiskey); how numbers are spoken, with headings, frequencies and the numbers in callsigns given digit by digit, and whole-hundred flight levels such as FL100 said with the word hundred, which CAP 413 says aims to reduce level busts; and the messages a pilot must read back in full, including level, heading and speed instructions, runway clearances, frequency changes and altimeter settings. Readbacks include the callsign, and when an aircraft reads back a clearance or instruction wrongly the controller says “negative” followed by the correct version. If you revise one area of radio rules before Stage 3, our suggestion is these.

The UK uses its own wake turbulence categories for arrivals, six of them from SUPER (the Airbus A380-800, Antonov AN-124 and AN-225) down to LIGHT, with UPPER MEDIUM, LOWER MEDIUM and SMALL being UK-only (CAP 493, Appendix B). The minima depend on the pair of categories and the phase of flight: on final approach a LIGHT behind a HEAVY needs 7 NM, two HEAVY aircraft 4 NM, and a HEAVY behind a LIGHT needs no spacing for wake reasons alone (other separation still applies). On the radio, time is UTC unless stated, on the 24-hour clock. Finally, know your employer: NATS’s careers page lists its two control centres, Swanwick and Prestwick, the airports where its controllers work, and three kinds of controller: Aerodrome (Tower), Area and Approach.

Keep practising the kinds of task you met at Stages 1 and 2 alongside this plan. NATS says only that Stage 3 includes “a retest of the previous tests whilst being observed,” without naming which, so our advice is to treat all of them as live until the day.