Skip to content

02.2 FIR, UIR & ACC

Training Objective

To ensure understanding of airspace divisions and control responsibilities within an FIR/UIR structure.


Key Knowledge

  • Definition of FIR and UIR
  • ACC responsibilities
  • Boundaries and lateral limits
  • Vertical division of airspace

Operational Application

Controllers shall:

  • Provide ATC service within assigned sector of the FIR/UIR
  • Coordinate with adjacent FIRs and sectors
  • Ensure correct transfer of control

1. Overview

Airspace is divided into regions to define responsibility for air traffic services.


2. Core Content

2.1 Flight Information Region (FIR)

  • Defined area where flight information and alerting services are provided
  • Usually surface to upper limits

2.2 Upper Information Region (UIR)

  • Upper portion of FIR
  • Typically above FL245 or as defined locally

2.3 Area Control Centre (ACC)

  • Provides en-route ATC services
  • Responsible for separation within FIR/UIR

3. Procedures

3.1 Transfer of Control

  • Aircraft shall be transferred at agreed coordination points
  • Control responsibility shall be clearly defined

3.2 Coordination Principles

  • Transfer of control and communication may occur at different points
  • Coordination shall be completed prior to boundary transfer
  • Estimates shall be passed in accordance with local procedures

4. Standards

  • FIR/UIR boundaries defined by ICAO and national authorities
  • Controllers shall not provide service outside designated airspace

5. Notes

  • Adjacent FIR coordination is critical in high-density regions