What is FAR 25.853?

The Federal Aviation Administration (FAA) enforces strict safety regulations for commercial aircraft. FAR 25.853 specifically dictates the flammability standards for compartment interiors. Any plastic component used in an aircraft cabin—from tray tables to overhead bins—must pass rigorous vertical burn tests to ensure they self-extinguish and do not contribute to a cabin fire.

The Challenge of Thermoforming Compliant Plastics

To meet FAR 25.853, engineers cannot use standard ABS or Polycarbonate. They must utilize highly specialized, inherently flame-retardant thermoplastics. These materials behave very differently during the vacuum forming process.

• Kydex (Acrylic-PVC alloy): This is the industry standard for aerospace interiors. It meets all flammability, smoke, and toxicity (FST) requirements while offering immense durability and chemical resistance. However, it requires precise, high-temperature heating to prevent surface degradation during forming.
• Ultem (PEI): For components requiring extreme heat resistance and structural integrity, Ultem is used. It is notoriously difficult to thermoform due to its very high glass transition temperature, requiring specialized high-wattage quartz heaters.

Our Process Controls

At M/S RV Chumble, forming aerospace-grade plastics requires perfect environmental control. We utilize advanced zoned heating to ensure the sheet reaches the exact pliability state without scorching the surface or triggering the flame-retardant additives before forming.