ILS Critical Area Fence

ILS Critical Area Fence

AviNeering’s ILS Critical Area Fence solution is a durable, ICAO-compliant physical barrier designed to safeguard the physical area around the Instrument Landing Systems (ILS). Installed around Localizer and Glide Path critical areas, the fence is placed to prevent unintentional incursions by vehicles or personnel, reducing the chance of causing signal disturbance during ILS operations.

The ILS Critical Area Fence is developed in accordance with ICAO Annex 10 and the European Guidance Material on Management of ILS Critical and Sensitive Areas (EUR Doc 040), which recommend the use of physical measures where procedural controls alone may be insufficient.

Why Critical Area Fence?

ILS Critical Area Fence

The performance of ILS systems is highly sensitive to objects within the defined critical areas. Even brief movement of aircraft, vehicles, or equipment inside these zones can cause reflections, interference, or multipath effects—potentially compromising approach guidance.

While procedural control and signage can reduce these risks, they are not foolproof. ICAO therefore recommends physical measures to ensure protection of the radiating environment.

ICAO Annex 10, Vol I §2.1.9.1:
“The ILS critical area is an area of defined dimensions about the localizer and glide path antennas where vehicles, including aircraft, are excluded during all ILS operations. The critical area is protected because the presence of vehicles and/or aircraft inside its boundaries will cause unacceptable disturbance to the ILS signal-in-space.”

AviNeering ILS Critical Area Fence provides a reliable and almost maintenance-free solution.

Key Features

Non-metallic construction
Designed for use within ILS radiation zones, the fence uses only non-conductive materials to eliminate the risk of signal reflections or multipath interference.

  1. Durable WPC Posts
    The posts are made from Wood-Plastic Composite (WPC), a material composed of wood fibers and thermoplastics. WPC is extremely durable and performs reliably in harsh conditions including UV radiation, high temperatures, humidity, and desert climates.

  2. Two barrier options

    • Alternative 1 – Polyester Rope: UV-stabilized, braided, and color-coded in red and white for visibility. Ideal for flexible, low-profile installations.

    • Alternative 2 – WPC Plank: Solid, long-life planks offering rigid separation with a 30+ year expected lifespan.

  3. Frangibility-compliant design
    Structurally tested to meet ICAO frangibility requirements. The fence collapses safely under impact by aircraft at speeds up to 140 km/h, limiting damage to both structure and aircraft.

  4. Color-through post pigmentation
    The coloring is embedded into the WPC material during the extrusion process. This prevents fading, peeling, or maintenance issues common with painted surfaces—ensuring long-lasting visibility without the need for repainting.

  5. Flexible sizing and layout
    Each fence is custom-designed to follow ILS critical area geometries (e.g., Normarc 7232 Localizer). Fence lengths and layouts vary per site, with examples ranging from 309 to 724 meters per ILS component.

ILS Critical Area Fence - Rope Barrier

ILS Critical Area Fence with Rope barrier

ILS Critical Area Fence with Plank barrier