Fire precautions

This regulation establishes fire safety requirements for cargo and baggage compartments on Part 121 aircraft. All compartments must protect critical systems from cargo damage, use flame-resistant materials, and not interfere with fire protection features.

Compartments are classified by accessibility and fire protection level:

• Class A: Crew can see and easily access the compartment in flight
• Class B: Crew can reach all areas with a hand extinguisher; requires smoke/fire detectors
• Class C: Limited access; requires detectors and built-in fire suppression systems
• Class D: Designed to contain fires completely without crew intervention
• Class E: Cargo-only aircraft cabins; requires detectors, ventilation shutoff capability, and maintained crew exit access

Each class has specific requirements for detection systems, suppression equipment, fire-resistant linings, and ventilation control. The classification determines what fire protection features the aircraft manufacturer must install, directly affecting how crews respond to cargo compartment fires and what cargo operations are permitted.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*