Visual Obstacle Marking Aids: Mobile Objects, Fixed Obstacles, and Marker Balls

010-09-05Pablo Asensio Martínez2026-03-271 min

Mobile Objects

  • Emergency vehicles: Preferably Red or Yellowish Green.
  • Service vehicles: Preferably Yellow.
  • All mobile objects must be marked with colors or flags.

Fixed Objects

  • Lighting:
    • Low, medium, or high intensity obstacle lights.
    • Must be visible from all angles in azimuth.
  • Marking (Flags):
    • Flags to mark fixed objects must be Orange or a combination of Orange and White (or Red and White).

Overhead Wires

  • Marker Balls:
    • Must be displayed alternately in White and Red or White and Orange.
    • Minimum diameter: 60 cm.
    • Purpose: To make visible wires (high tension lines, river crossings) that pose a hazard to navigation.
Written and reviewed by

Pablo Asensio · 2026-03-27

Aeronautical engineer. Passed the thirteen EASA ATPL(A) theoretical knowledge exams studying from these very notes. Writes and reviews each topic against the Part-FCL Learning Objectives.

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