The FAA published a notice of proposed rulemaking (NPRM) on July 3 to change certain fire protection regulations for interior compartments on transport category airplanes. Proposed changes would affect materials ranging from floor covering to textiles to acrylic windows and signs to insulation.

The proposal would shift from "detailed, prescriptive requirements into simpler, performance-based standards,” establishing two performance-based categories: in-flight fire protections and protections to maximize escape time from post-crash fires.

In creating the two performance-based categories, the FAA cited differing hazards from post-crash versus in-flight fires. In a crash, combustion of spilled fuel is a primary hazard making evacuation time critical. The FAA noted that “roughly 90 percent of actual evacuations are completed within 5 minutes.”

In-flight fires become most critical when starting in an area inaccessible to a person with a handheld fire extinguisher, e.g., in cargo compartments or behind interior panels such as sidewalls or ceilings. In contrast, fires in areas accessible to a person with a fire extinguisher are still a concern but “much less likely to evolve into a threat to the airplane,” the FAA wrote. These differences require different regulatory approaches, the agency added.

The NPRM would extend fire-protection requirements to materials extensively used in inaccessible areas. Additionally, the FAA's proposal would remove mandatory test methods and allow applicants, in certain cases, to demonstrate compliance without conducting testing or providing independent substantiation of the flammability characteristics of proposed materials.

The proposed changes stem from a long history of work on aircraft fire safety. In 2010, the agency tasked an Aviation Rulemaking Advisory Committee to start a flammability review and provide recommendations. This work changed over time, finally resulting in the ‘‘Materials Flammability Working Group Continuation of Task Report,’’ dated October 7, 2015. The FAA’s new proposal is based on the working group’s recommendations.

Comments on the NPRM are due October 1.