---
title: "CAT.OP.MPA.100 Use of air traffic services — Part-CAT · Avioverse"
description: "The operator shall ensure that: air traffic services (ATS) appropriate to the airspace and the applicable rules of the air are used for all flights…"
url: "https://avioverse.aero/regulations/easa/air-ops/part-cat/subpart-b/cat-op-mpa-100"
---

# CAT.OP.MPA.100 Use of air traffic services

ANNEX IV (Part-CAT) · Regulation (EU) No 965/2012 · EAR revision 27 Mar 2026

IR Implementing rule

## CAT.OP.MPA.100 Use of air traffic services

(a) The operator shall ensure that:

(1) air traffic services (ATS) appropriate to the airspace and the applicable [rules of the air](https://avioverse.aero/glossary/easa/rules-of-the-air) are used for all flights whenever available;

(2) in-flight operational instructions involving a change to the ATS flight plan, when practicable, are coordinated with the appropriate ATS unit before transmission to an [aircraft](https://avioverse.aero/glossary/easa/aircraft).

(b) Notwithstanding (a), the use of ATS is not required unless mandated by air space requirements for:

(1) operations under VFR by day of other-than complex motor-powered aeroplanes;

(2) helicopters with an MCTOM of 3 175 kg or less operated by day and over routes navigated by reference to visual landmarks; or

(3) local [helicopter](https://avioverse.aero/glossary/easa/helicopter) operations (LHOs), provided that search and rescue service arrangements can be maintained.

IR · CAT.OP.MPA.100 — Regulation (EU) No 965/2012 · Regulation (EU) 2021/1296 · Air OPS Easy Access Rules · EAR revision 27 Mar 2026

GM Guidance material

## GM1 CAT.OP.MPA.100(a)(2) Use of air traffic services

IN-FLIGHT OPERATIONAL INSTRUCTIONS

When coordination with an appropriate air traffic service (ATS) unit has not been possible, in-flight operational instructions do not relieve a commander of the responsibility for obtaining an appropriate clearance from an ATS unit, if applicable, before making a change in flight plan.

GM · GM1 CAT.OP.MPA.100(a)(2) — Regulation (EU) No 965/2012 · ED Decision 2014/015/R · Air OPS Easy Access Rules · EAR revision 27 Mar 2026

[All rules in SUBPART B: OPERATING PROCEDURES](https://avioverse.aero/regulations/easa/air-ops/part-cat/subpart-b)

Consolidated from the EASA Easy Access Rules (revision 27 Mar 2026, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.