This is a practical, operator‑level look at how an ERJ‑145’s onboard fire suppression and airport rescue and firefighting (ARFF) foams interact in a post‑crash, fuel‑fed fire scenario. I write from a line pilot and safety consultant perspective: what the systems can realistically do, where they are likely to fail, and what steps crews and aerodromes can take to maximize survivability.

Onboard suppression basics The ERJ‑145 family carries built‑in engine and APU fire bottles and—on many fitted aircraft—a baggage/cargo compartment extinguishing system that can be actuated from the flight deck. The manufacturer procedures show a one‑shot bottle arrangement for engine/APU protection and a cockpit‑operable baggage extinguish button with a stated extinguishing duration for the baggage system on ERJ documentation roughly on the order of minutes of agent discharge and smoke control capability. The ERJ AOM also emphasizes single‑discharge logic for engine bottles and cautions that baggage extinguishing systems are finite resources.

What that means in practice is simple. Built‑in bottles are designed to attack localized engine or APU fires and to give the crew time to shut down systems and land. They are not designed to extinguish a large external pool fire or a sustained fuselage burn fed by ruptured tanks. In other words, they can buy time and prevent propagation from a nacelle or compartment, but they will not stop an intense post‑crash fuel‑pool fire by themselves.

Why agent choice and supply matter Historically, Halon 1301 and Halon blends were the standard for aircraft fixed systems because of rapid knockdown, low residue, and negligible electrical conductivity. Production of virgin Halon ceased under international phase‑out agreements, and aviation relies on reclaimed stocks and critical‑use supplies while alternatives have been certified for some applications. The regulatory and practical reality is that aircraft built systems still commonly use Halon or banked Halon for some roles because equivalent mass‑ and performance‑balanced replacements are limited for certain engine and nacelle protections. That supply constraint affects maintenance and recharging timelines after a discharge.

ARFF foam: what it will and will not do A large portion of post‑crash destruction is caused by ground pool fires. External aqueous foams applied by ARFF apparatus are the primary tool for controlling and extinguishing large hydrocarbon fires. International guidance describes standard foam performance tests and sets application rates and extinction performance targets: properly applied foam meeting those performance levels can extinguish a representative jet fuel tray test within specified times and resist reignition for a measured interval. Those test methods are useful baselines. In the field there are complicating factors: breakup of tanks, spreading fuel, obstacles, wind, and aircraft geometry all increase the challenge compared with a controlled tray test.

Recent operational constraints: PFAS and foam transition Airports and ARFF providers are under growing pressure to move from legacy AFFF and fluorinated foams because of PFAS environmental and drinking water concerns. Regulatory and military programs have driven a transition path to performance‑tested fluorine‑free foams (F3) that can meet new military and civil specifications. The practical upshot is that, at many aerodromes, foam type and stock levels are in transition. That transition must preserve real‑world extinguishing effectiveness for hydrocarbon pool fires while also managing environmental impacts. Operators and aerodromes need to validate chosen fluorine‑free concentrates against the ICAO/industry performance levels and adjust application tactics accordingly.

Putting those pieces together for an ERJ‑145 post‑crash scenario 1) Immediate survivability window. If the airframe remains occupiable after impact, the critical survival window starts at impact and ends when the cabin environment becomes untenable from heat, smoke, or flame. Post‑crash fire is the single most critical post‑impact factor reducing survivability in otherwise survivable accidents. Rapid evacuation and preventing fire growth are priorities.

2) Onboard bottles buy time, but they do not stop pool fires. Expect engine/APU bottles to be useful for nacelle fires or small compartment fires. They will not put out a fuel‑fed pool fire that has spread beneath the fuselage or externally along the wing and ground. Crews should use them immediately for engine/APU indications, then focus on evacuation when the aircraft stops.

3) ARFF is decisive for large external fires. Once a pool fire is established the ARFF response, foam type, application rate, and available quantity determine whether the fire is rapidly suppressed or allowed to consume the airframe. ICAO performance levels give useful benchmarks: well‑trained crews using appropriate concentrates can extinguish representative fuel fires quickly in tests, but real spreads are worse than test trays and require more agent and coordinated tactics.

4) Resource mismatches are common at remote fields. Smaller airports frequently have limited ARFF categories, smaller foam reserves, and longer mutual‑aid timelines. Operators flying ERJ‑145s into remote aerodromes should confirm ARFF category and foam stock, brief passengers on evacuation, and consider landing weight and fuel considerations where practicable to reduce post‑impact fuel load. (See aerodrome certification guidance and ARFF category definitions.)

Practical recommendations (operator and aerodrome level)

  • Preflight and dispatch: verify destination ARFF category, foam type on hand, and NOTAMs identifying runway works or hazards. If ARFF capability is below the operator’s risk threshold, consider operational mitigations or diversion.

  • Aircraft readiness: ensure engine/APU/baggage extinguishers are maintained and charged. Because Halon recharges depend on reclaimed stocks, keep maintenance records and plan for longer‑lead recharges where bottle discharge is a safety event.

  • Crew procedures: prioritize rapid, command‑led evacuation when fire or smoke threatens the cabin. Use built‑in extinguishers for nacelle and compartment fires per checklist, but do not delay evacuation to re‑attempt extinguishment once evacuation is the safer course. Train for smoke and heat‑impaired exits.

  • Aerodrome actions: maintain foam stocks sized to ICAO application standards and document transition plans if replacing AFFF with approved F3 concentrates. Drill coordinated ARFF tactics for aircraft‑type specific threats and ensure arrival‑to‑extinguish response times meet applicable standards.

  • Investigation and learning: when an aircraft fire occurs, detailed analysis of timeline, extinguisher use, ARFF arrival, and foam application should feed back into operations and training. Data on real world performance against representative tests is the only way to refine tactics and procurement choices.

Bottom line For an ERJ‑145 involved in a survivable impact, built‑in extinguishers can be life‑saving for localized nacelle or compartment fires but are not a substitute for timely, well‑resourced ARFF foam application against fuel‑fed pool fires. The weakest link is often the external response: foam type, quantity, and responder training matter. Operators and aerodromes need to be explicit in planning for that phase of the incident, especially at remote fields, and they must manage the halon‑bank reality on the aircraft side while adopting vetted fluorine‑free foams where and when those concentrates demonstrably meet performance levels. In short, buy time in the airplane, and make sure the ground buys the rest.