CABIN ALTITUDE

Condition: Cabin altitude is excessive.

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Memory Items 🔴

CAUTION

MEMORY ITEMS — MUST BE COMPLETED FROM MEMORY

1. Don the oxygen masks.
2. Establish crew communications.
3. Check the cabin altitude and rate.
4. If the cabin altitude is uncontrollable:
   • PASS OXYGEN switch … Push to ON and hold for 1 second
   • Without delay, descend to the lowest safe altitude or 10,000 feet, whichever is higher.
   • To descend:
     • Move the thrust levers to idle
     • Extend the speedbrakes
     • If structural integrity is in doubt, limit airspeed and avoid high maneuvering loads
     • Descend at Vmo/Mmo

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Decision Flowchart

flowchart TD
    A["CABIN ALTITUDE Warning"] --> B["Don oxygen masks"]
    B --> C["Establish crew communications"]
    C --> D["Check cabin altitude and rate"]
    D --> E{"Cabin altitude<br/>controllable?"}
    E -->|No — Uncontrollable| F["PASS OXYGEN switch ON<br/>(hold 1 sec)"]
    F --> G["Emergency Descent:<br/>Thrust idle, Speedbrakes extend<br/>Descend at Vmo/Mmo<br/>to lowest safe alt or 10,000ft"]
    E -->|Yes — Controllable| H["Continue normal operation"]

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Reference Items 🟢

• Step 5: If the cabin altitude is controllable:
  • Continue normal operation.

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Notes & Gotchas

WARNING

• 메모리 아이템에서 가장 중요: Controllable vs Uncontrollable 판단
• Uncontrollable이면 즉시 emergency descent — 절대 지체하지 말 것
• PASS OXYGEN 누르기 전에 “cabin altitude and rate” 확인 — 만약 controllable이면 descent 불필요
• Structural integrity 의심 시 (예: 동체 파열) Vmo/Mmo가 아닌 reduced speed로 강하
• Emergency descent 중 ATC 통보: Squawk 7700, “MAYDAY” 선언

Cross-References