Air traffic management (ICAO Annex 11 / Doc 4444)

General Provisions for Air Traffic Services

ATC service applies to: all IFR flights in airspace Classes A through E; all VFR flights in Classes B, C and D; all special VFR flights; and all aerodrome traffic at controlled aerodromes SERA.8001@2025-05-01.

To provide ATC service, a unit must track each aircraft's intended and actual progress, determine relative positions of known aircraft, issue clearances, instructions and information to prevent collision and maintain orderly traffic flow, and coordinate clearances with adjacent units whenever an aircraft might otherwise conflict with traffic operated under the control of such other units, and before transferring control SERA.8005@2025-05-01.

Separation

Clearances must provide separation: between all flights in Classes A and B; between IFR flights in Classes C, D and E; between IFR and VFR in Class C; between IFR and special VFR flights; and between special VFR flights unless otherwise prescribed by the competent authority SERA.8005@2025-05-01. Separation is obtained by vertical means (different cruising levels; minimum 300 m / 1,000 ft up to and including FL 410, 600 m / 2,000 ft above; geometric height shall not be used), longitudinal means (time or distance intervals along the same, converging or reciprocal track), or lateral means (different routes or geographic areas) SERA.8005@2025-05-01.

In Classes D and E, below 3,050 m (10,000 ft), a flight may be cleared to maintain own separation during climb or descent in day VMC, if both pilots consent and the competent authority permits SERA.8005@2025-05-01. The 250 kt speed limit in those classes gives pilots sufficient time to observe and avoid GM1 SERA.8005@2026-07-18; under such a clearance ATC provides no separation and the crew bears full collision-avoidance responsibility GM3 SERA.8005@2026-07-18. An IFR crew on such a clearance that observes conditions deteriorating should inform ATC before entering IMC and comply with any alternative instructions given GM2 SERA.8005@2026-07-18.

An IFR flight may be cleared for a visual approach if the pilot maintains visual reference to terrain and either the ceiling is at or above the initial approach segment level, or the pilot reports that a visual landing can be completed with reasonable assurance AMC1 SERA.8005@2026-07-18. Separation minima are selected by the responsible ANSP and approved by the competent authority SERA.8010@2025-05-01.

Aerodrome control service procedures and radar service procedures as detailed in ICAO Doc 4444 (PANS-ATM) are not covered by the EU corpus (ICAO-framework material).

ATC Clearances and Flight Plan Adherence

Clearances are issued solely to expedite and separate traffic and must be issued early enough for the aircraft to comply SERA.8015@2025-05-01. Controlled flight requires a prior clearance obtained via flight plan SERA.8015@2025-05-01. Speed control instructions should remain in effect until explicitly cancelled or amended by ATC AMC1 SERA.8015@2026-07-18; flight crews should comply with published SID and STAR speed restrictions unless ATC explicitly cancels or amends them AMC2 SERA.8015@2026-07-18.

A controlled flight must adhere to its current flight plan SERA.8020@2025-05-01. Sustained cruise speed deviations exceeding ±Mach 0.02 or ±19 km/h (10 kt) TAS at cruising level must be reported to ATS SERA.8020@2025-05-01; time estimate changes exceeding 2 minutes for the next applicable reporting point, FIR boundary or destination aerodrome, whichever comes first, must also be reported — except where ADS-C is activated and serviceable in airspace where ADS-C services are provided SERA.8020@2025-05-01. Position reports at compulsory points must contain aircraft identification, position, time, and speed if assigned by ATC SERA.8025@2025-05-01; where no designated reporting points exist, reports are due as soon as possible after the first half hour and at hourly intervals thereafter AMC1 SERA.8025@2026-07-18.

A controlled flight shall maintain continuous air-ground voice communication watch on the appropriate ATC frequency SERA.8035@2025-05-01 and advise ATS when ceasing to be subject to ATC service — except when landing at a controlled aerodrome SERA.8030@2025-05-01.

Flight Information Service

FIS is provided to all aircraft likely to be affected — those under ATC and those otherwise known to ATS SERA.9001@2025-05-01. Receiving FIS does not relieve the pilot-in-command of any responsibility; the final decision on any suggested alteration of flight plan remains with the pilot-in-command SERA.9001@2025-05-01. Where both ATC and FIS are provided, ATC takes precedence whenever the provision of air traffic control service so requires SERA.9001@2025-05-01. FIS covers SIGMET and AIRMET, volcanic activity, radioactive and toxic releases, navigation service changes, aerodrome condition updates, unmanned balloons and aircraft, and other safety-relevant data SERA.9005@2025-05-01. VFR flights additionally receive information on traffic and weather conditions that are likely to make operation under the visual flight rules impracticable SERA.9005@2025-05-01. Collision hazard information reflects only known activities; ATS cannot guarantee completeness or accuracy due to coverage and reporting limitations GM1 SERA.9005@2026-07-18.

Phraseology

Standardised phraseology shall be used whenever it has been specified; plain language is used only where standardised phraseology cannot serve the intended transmission SERA.14001@2025-05-01. An all-stations general call expects no reply unless individual stations are subsequently called GM2 SERA.14001@2026-07-18.

Communication Failure and Contingencies

On communication failure, the crew attempts re-contact on the previous channel, then other appropriate channels, then all available means including data link, satellite voice and mobile phones SERA.14083@2025-05-01. If unsuccessful: squawk Mode A Code 7600. VFR flights must continue in VMC, land at the nearest suitable aerodrome, and report arrival by the most expeditious means; IFR flights follow the prescribed lost-communications routing and descent procedure SERA.14083@2025-05-01. Except when an IFR aircraft experiencing communication failure transmits A7601, ATC applies separation on the assumption the IFR aircraft follows the standard lost-communications procedure until: it is determined the aircraft is following a differing procedure (e.g. observing that the aircraft sets transponder code 7601); electronic or other aids confirm that different actions may be taken without impairing safety; or positive confirmation is received that the aircraft has landed AMC1 SERA.14083@2026-07-18.

Emergencies — Unlawful Interference, Straying and Interception

An aircraft subjected to unlawful interference shall endeavour to squawk 7500 and notify ATS of the situation and any flight plan deviation; the pilot-in-command shall attempt to land as soon as practicable at the nearest suitable aerodrome or operating site or at a dedicated aerodrome or operating site assigned by the competent authority, unless considerations aboard the aircraft dictate otherwise SERA.11005@2025-05-01. ATS shall respond promptly and continue transmitting safety-relevant information SERA.11005@2025-05-01. Where radio contact is not possible, the aircraft should maintain assigned track and level if feasible; if a deviation becomes necessary and no applicable regional procedures have been established, it should be offset by 150 m (500 ft) from normal IFR cruising levels in a 300 m VSM area, or 300 m (1,000 ft) in a 600 m VSM area GM1 SERA.11005@2026-07-18.

When intercepted, the pilot-in-command shall follow the intercepting aircraft's visual signals, notify ATS if possible, attempt radio contact on 121.5 MHz (and 243 MHz if needed), and — unless otherwise instructed — select Mode A Code 7700 SERA.11015@2025-05-01. Interception of civil aircraft is a last resort and should be limited to determining the identity of the aircraft, returning it to its planned track, directing it beyond national airspace boundaries, guiding it away from a prohibited, restricted or danger area or congested areas, or instructing it to land at a designated aerodrome AMC1 SERA.11015@2026-07-18. A strayed aircraft is assisted through all available ATS means, with adjacent ATS units and military authorities informed as appropriate SERA.11010@2025-05-01.

This block connects to your school's own Operations Manual (OM-A/B/C/D). In the full product it shows, cited to your manual, how YOUR organisation implements the regulation above — private to your school. (Demo placeholder.)

The following cases are labeled illustrative context only and do not constitute regulatory authority.

Communication failure and interception: Romania, July 2026. A Cathay Pacific flight temporarily lost radio contact with ATC over Romanian airspace and was subsequently intercepted by NATO fighter jets CASE-3. NATO early warning and control aircraft were simultaneously operating in the wider region off the Black Sea coast CASE-1. Hong Kong's Civil Aviation Department ordered a comprehensive carrier review and expressed serious concern for a second consecutive day CASE-3. This sequence illustrates why communication failure procedures and interception visual signal recognition are practical flight skills: an aircraft that becomes unidentified — even briefly and unintentionally — can trigger a military response. The interception scenario played out exactly as the regulatory framework anticipates, activating the chain from unidentified aircraft procedures through to fighter intercept.

Dual engine failure and forced landing: Texas, June 2026. Both engines on a small business jet flamed out before it crashed on a Laredo highway; the NTSB preliminary report confirmed that the crew could not reach a nearby airport CASE-2. This illustrates the contingency where a crew must deviate from an ATC clearance immediately on emergency authority, accepting that ATC coordination becomes a secondary priority to aircraft survival. The obligation to notify ATS as soon as circumstances permit — rather than before acting — is the key regulatory distinction this case demonstrates.