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04.2 Sequencing & Spacing

Training Objective

To ensure correct sequencing and spacing of aircraft in an en-route environment.


Key Knowledge

  • Longitudinal spacing
  • Speed control
  • Sequencing techniques

Operational Application

Controllers shall:

  • Establish and maintain appropriate spacing between aircraft
  • Sequence traffic to avoid conflicts
  • Use speed and level adjustments effectively

1. Overview

Sequencing ensures aircraft follow an orderly flow, while spacing maintains safe separation and efficiency.


2. Core Content

2.1 Longitudinal Spacing

  • Based on speed and distance
  • Prevents overtaking conflicts

2.2 Speed Control

  • Primary tool for fine adjustments
  • Reduces need for vectoring

2.3 Level Management

  • Vertical separation used to support sequencing

3. Procedures

3.1 Speed Instructions

  • Shall be clear and achievable
  • Shall consider aircraft performance

3.2 Sequencing Strategy

  • Faster aircraft shall not be placed behind slower traffic without spacing

4. Standards

  • Separation minima shall not be infringed
  • Spacing shall be sufficient to prevent conflict

5. Notes

  • Poor sequencing leads to unnecessary workload