Overview
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Replace with overview of detection loops, bottles, and discharge logic.
Fire detection and extinguishing covers the four engine nacelles, APU, main cargo compartments, and (on freighter) the cargo deck. Each protected area has redundant detector loops (Loop A / Loop B) feeding a fire/overheat detection card. Single-loop activation triggers a fault; both loops in alarm trigger a fire warning.
Architecture
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<FireProtectionSchematic /> — bottles, detector loops, distribution to nozzles.Components
| Engine Fire Bottles | 4 (one per nacelle), discharge to its own engine only |
| APU Fire Bottle | 1, in tailcone — auto-discharges on ground |
| Cargo Fire Bottles | 2 (Halon) — sequenced metered discharge |
| Detection Loops | Dual loop (A + B) for all areas |
| Wheel Well Overheat | Single loop, EICAS message |
Engine Fire Procedure (Memory)
MEMORY ITEM — Engine Fire / Severe Damage / Separation
- Autothrottle (affected) — DISCONNECT
- Thrust lever (affected) — CLOSE
- Fuel control switch (affected) — CUTOFF
- Engine fire handle (affected) — PULL
- If fire warning persists after 30 sec — rotate handle to discharge bottle
- If still fire — rotate handle other direction to discharge 2nd bottle
APU Fire
MEMORY ITEM — APU Fire
- APU fire handle — PULL
- Rotate handle — DISCHARGE (auto-discharges on ground)
Cargo Fire
MEMORY ITEM — Cargo Fire
- Cargo fire ARM switch (affected) — PUSH
- Cargo fire DISCH switch — PUSH
- Plan to land at nearest suitable airport
Limits
- Bottle discharge limited to designated area (no cross-discharge between engines)
Notes / Personal
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User notes.