Aerospace Plastics: Materials, FST Compliance, and Where Each One Belongs

By B. Decker  •  Updated August 2026  •  10 min read

Total Plastics fabricates and ships aerospace-grade acrylic, flexible polyolefin, and polycast out of our Kalamazoo, Michigan headquarters and our Rhode Island branch, cutting FST-rated sheet for contractors and OEMs across the country. This guide also covers the broader landscape of aerospace plastics, including high-performance materials like PEEK and PAI that fall outside Total's current standard aerospace line, so you understand where each material fits before you go looking for a source.

What Makes a Plastic "Aerospace-Grade"?

Three things separate an aerospace-grade plastic from an industrial one: weight, heat performance, and fire safety documentation. Weight matters because every pound saved on a commercial aircraft translates directly into fuel savings over the life of the plane, which is why plastics have replaced metal in thousands of non-structural and semi-structural components. Heat performance matters because parts near engines, exhaust systems, and avionics bays can see sustained temperatures that would soften or deform a standard commodity plastic. Fire safety matters because cabin interior materials are legally required to meet flammability, smoke density, and toxicity limits before they can go on an aircraft at all.

None of these materials are structural in the way that airframe aluminum or carbon fiber composite is. Aerospace plastics fill everything around and inside the structure: interiors, insulation, ducting, transparencies, bushings, seals, and electrical components.

FST Compliance: FAR 25.853, OSU 65/65, and UL 94

Any plastic used inside an aircraft cabin has to clear FST testing: flammability, smoke density, and toxicity. The FAA's governing standard is FAR 25.853, which sets vertical burn requirements and, for larger interior components, a heat release test known as OSU 65/65. Airbus and Boeing layer their own internal specs on top (ABD 0031 and D6-36440, respectively), but they're built around the same FAA framework. UL 94 flammability ratings show up frequently in aerospace plastic spec sheets as a secondary reference point, even though it's not itself an aviation standard.

Here's the distinction that actually matters when you're speccing a job: some plastics meet FST requirements inherently, with no modification. Others need a flame-retardant additive package to get there.

High-Heat Structural Plastics: PEEK, PAI, and PPS

PEEK (polyetheretherketone) is the workhorse of this category: strong, chemically resistant, and rated for continuous service in the neighborhood of 480°F depending on grade. It shows up in bushings, bearings, electrical connector components, and structural brackets where metal would add unnecessary weight.

PAI (polyamide-imide, commonly sold under the Torlon trade name) has the highest glass transition temperature of the commercially available aerospace thermoplastics, which makes it the default choice for parts that sit closest to sustained high heat, think engine-adjacent bushings and seals rather than cabin components.

PPS (polyphenylene sulfide) trades a bit of PAI's heat ceiling for excellent chemical resistance and inherent flame retardance. It's a common pick for electrical housings and connectors where both heat and chemical exposure are factors. PEI (polyetherimide, commonly Ultem) rounds out this group: an amorphous, dimensionally stable polymer with built-in flame retardance that's widely specified for structural brackets and electrical components alongside PEEK.

Transparent Materials: Acrylic vs. Polycarbonate

Acrylic (PMMA) is the standard for windows and windscreens where optical clarity is the top priority. It scratches more easily than polycarbonate but holds clarity and UV stability better over time, and it's the more common choice for cabin windows on commercial aircraft.

Polycarbonate (PC) trades some optical performance for dramatically better impact resistance, which is why it shows up in canopies, dust covers, and any transparency where impact risk outweighs the need for the clearest possible view.

FST-Rated Interior Sheet: PVC/Acrylic Alloy and PPSU

This is where a common misconception needs correcting. PVC on its own isn't used for fuel tanks or heat shields. Its heat performance and impact strength don't fit either application. What PVC does show up in, extensively, is wire and cable protection, ducting, and, more specifically, PVC/acrylic alloy sheet, an extruded thermoplastic that's become one of the most widely specified materials for thermoformed aircraft interior components.

PVC/acrylic alloy sheet is built to meet FAR 25.853 flammability requirements and commonly carries a UL 94 V-0 rating out of the box. It thermoforms into deep draws and sharp corners more easily than most alternatives, which is why it's the material behind instrument panel housings, class dividers, bulkhead laminates, galley and lavatory components, sidewalls, and window reveals on commercial, military, and private aircraft.

PPSU (polyphenylsulfone) fills a similar role for cabin components that need both FST compliance and higher-temperature performance than PVC/acrylic alloy can offer.

Low-Friction Plastics: PTFE, FEP, and PFA

PTFE, FEP, and PFA are the fluoropolymer family, and this is where a genuinely low coefficient of friction actually matters: seals, bushings, wire insulation, and bearing surfaces that need to move against another part with minimal resistance and minimal wear. That's a different benefit than aerodynamic drag reduction, which comes from the aircraft's external shape and surface finish, not from the friction coefficient of an interior plastic. These materials also bring strong chemical resistance, which is why FEP and PFA show up frequently in wire and cable jacketing exposed to fuel, hydraulic fluid, or de-icing chemicals.

Quick-Reference Material Comparison

Material	FST Compliant As-Is?	Typical Use
PEEK	Yes	Bushings, bearings, structural brackets
PAI (Torlon)	Yes	Engine-adjacent seals and bushings
PPS	Yes	Electrical housings, connectors
PEI (Ultem)	Yes	Structural brackets, electrical components
PPSU	Yes	High-temp cabin components
PVC/Acrylic Alloy	Yes (UL 94 V-0 typical)	Thermoformed interior panels
PA (Nylon)	Usually needs additive	Fasteners, general mechanical parts
Acrylic (PMMA)	N/A, not interior sheet	Windows, windscreens
Polycarbonate (PC)	N/A, not interior sheet	Canopies, dust covers, impact-critical transparencies
PTFE / FEP / PFA	N/A, non-interior applications	Seals, bearings, wire and cable jacketing

Choosing the Right Aerospace Plastic

Where These Materials Show Up on the Aircraft

• Cabin interiors: wall panels, luggage compartments, tray tables, sidewalls, kick panels (PVC/acrylic alloy, PPSU)
• Transparencies: windows, windscreens, canopies, dust covers (acrylic, polycarbonate)
• Mechanical components: bushings, bearings, seals, fasteners (PEEK, PAI, acetal, PTFE)
• Electrical systems: connector housings, wiring conduits, wire and cable jacketing (PPS, PEI, FEP, PFA)
• Ducting and insulation: ventilation ducting, collapsible air duct ribs, thermal and electrical insulators (PVC, PTFE)
• Landing gear and structural support: non-structural landing gear components, cabinetry (PEEK, PEI)

Bottom Line

Aerospace plastic selection comes down to three questions: how much heat will this part see, does it need to meet FAR 25.853 for cabin use, and does it need to be transparent or low-friction. PEEK and PAI cover the high-heat structural work. PVC/acrylic alloy and PPSU cover FST-rated interior panels. Acrylic and polycarbonate cover transparencies. PTFE, FEP, and PFA cover seals and bearings. Match the material to the actual environment the part will sit in, not just the general category of "aircraft plastic," and the spec sheet will tell you the rest.

Frequently Asked Questions

This article is for informational purposes only. Material selection, FST compliance, and airworthiness approval must follow the applicable FAA, EASA, and OEM specifications for your specific aircraft and application. Verify current certifications and grade-specific data with the manufacturer before specifying any material for a certified aircraft part.