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Commercial pilot · ACS CA.IX.A · lesson pack

Emergency Descent

Why this one matters

Fire and smoke leave minutes; a decompression leaves seconds of useful consciousness. A commercial pilot needs to get down quickly without overstressing the airplane, losing control or colliding with traffic, while managing passengers and ATC.

1 · Know these cold

  • •Each cause has its own first actions. Depressurization: oxygen masks on first (100%), talk to the passengers, then descend promptly to about 10,000 feet or the minimum safe altitude. Engine fire: starve it first (mixture idle cutoff, fuel selector off) per the POH, then descend and land as soon as possible. Smoke: the POH checklist, then descend and land. Useful consciousness depends on altitude: about 3 to 5 minutes at 25,000 feet, 30 to 60 seconds at 35,000, less after a rapid decompression.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures; AIM 8-1-2; AC 61-107, Aircraft Operations at Altitudes Above 25,000 Feet MSL and/or Mach Numbers Greater Than .75)
  • •Power to idle (propeller forward if controllable), roll into a 30-45° bank to keep a positive load factor, and set the POH speed and configuration.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures; Commercial Pilot ACS (FAA-S-ACS-7B), CA.IX.A.S4)
  • •Fly the POH emergency-descent speed: the maximum allowable for the configuration (it may be VNE clean in smooth air, or VLE or VFE configured). In turbulence, slow to VA for the current weight (lower when lighter) or the POH turbulence speed, never above VNE, VLE or VFE. VNO is only the top of the green arc, for smooth air.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)
  • •Clear below before and during the descent; you're descending through other traffic.(AC 90-48, Pilots' Role in Collision Avoidance)
  • •Pick where you're going on the way down: the nearest suitable airport, with wind, terrain and glide distance in mind.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)
  • •Commercial standard: clear the area (S1); POH airspeed and configuration (S2); keep oriented and plan a smooth recovery (S3); bank 30-45° (S4); airspeed +0/-10 knots and level off ±100 feet (S5); checklists (S6); SRM (S7).(Commercial Pilot ACS (FAA-S-ACS-7B), CA.IX.A.S1-S7)
  • •Declare on the frequency you're on and squawk 7700; use 121.5 MHz only if you aren't talking to ATC.(AIM, Chapter 6, Emergency Procedures)

2 · The lesson

When and how
  • Engine or cabin fire and smoke: descend and land as soon as possible. Decompression in a pressurized airplane: masks, then descend promptly to about 10,000 feet or the minimum safe altitude, then divert as needed. A critical medical problem: declare and divert to the nearest suitable airport, expedited, which isn't necessarily a maximum-rate descent.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)
  • Technique: clear first, looking below in the turn for traffic and a landing area; throttle idle, propeller forward, then roll into a 30-45° bank as the nose comes down so the load factor stays positive (no pushover); gear and flaps as the POH says; coordinated. The bank raises the stall speed and a spiral can build speed fast, so divide your attention. Level off by leading it about 10% of the descent rate, raising the nose smoothly.(Your airplane's POH/AFM; Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)
Speeds and performance
  • The POH gives the speed: the maximum allowable for the configuration (VNE clean in smooth air, or VLE with the gear down). Know the number for your checkride airplane. In turbulence, slow to VA for your weight or the POH turbulence penetration speed.(Your airplane's POH/AFM)
  • With an engine fire, starve it first by the POH checklist (mixture idle cutoff, fuel selector off, fuel pump off), then descend and land as soon as possible. A faster descent may blow out the fire, but the fire may have weakened the structure, so a slower descent puts less stress on it; your POH decides. Never restart an engine whose fire appeared to go out. In a complex airplane, extending the gear (within VLE) adds drag and steepens the descent.(Your airplane's POH/AFM; Airplane Flying Handbook (FAA-H-8083-3C), Transition to Complex and High-Performance Airplanes)
  • In training only: end the practice descent once it's established and stable, and avoid long practice descents that overcool a piston engine. Never let that delay a real emergency descent.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Complex and High-Performance Airplanes)
Where you're going
  • Use the GPS nearest function and the chart to pick a suitable airport early; consider wind, terrain, obstacles and runway length.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)
  • Clear below in the bank, and keep scanning on the way down.(AC 90-48, Pilots' Role in Collision Avoidance)
Staying ahead
  • Fly the airplane first. Then the checklist, then communicate: tell ATC, squawk 7700 if needed. Divide attention between the emergency and the airplane.(Airplane Flying Handbook (FAA-H-8083-3C), Emergency Procedures)

Want it all on one page, with scenarios? Read the full lesson.

On the flight

ACS standards

  • The POH speed and configuration for the scenario (S2); bank between 30° and 45° to keep positive load factors (S4).(Commercial Pilot ACS (FAA-S-ACS-7B), CA.IX.A.S2, S4)
  • Airspeed +0/-10 knots; level off at the specified altitude ±100 feet; complete the checklists.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.IX.A.S5-S6)

What your instructor is watching for

Your instructor watches for clearing, a prompt power reduction and bank, the POH speed and configuration within limits, divided attention, a planned landing area, a smooth level-off, and the checklist.

3 · Say it out loud

Answer each one out loud, then check yourself and mark how it went.

  1. Remember Recall it

    “Why bank 30 to 45 degrees in an emergency descent?”

  2. Understand Explain why

    “Why might the POH have you extend the gear?”

  3. Apply Use it on a flight

    “Smoke fills the cabin at 9,000 feet with passengers aboard. Walk me through it.”

4 · Common mistakes

  • Diving with power on.

    Airspeed builds past limits.

    Instead: Power to idle first.

  • Extending gear or flaps above limits.

    Damage to gear or flaps.

    Instead: Only within VLE and VFE.

  • Not clearing below.

    You descend through traffic.

    Instead: Look below in the bank.

5 · Quick check

Answer, then reveal. Flag anything you want to see again.

  1. 1. What bank angle is used?

  2. 2. What are the commercial tolerances?

  3. 3. What speed applies in turbulence?

  4. 4. Which transponder code signals an emergency?

  5. Scenario5. An engine fire at altitude. What does the POH typically call for?

Trained it? Now prove it: practice emergency descent out loud with our examiner.

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Connect it

One situation that runs across this lesson and its neighbors in the same ACS area. Decide first, then check.

Connect it · Emergency Operations

Over forest, you smell burning insulation and see smoke from behind the panel.

How do the malfunction, the descent and the landing tie together? Decide, then see the worked answer

Treat it as an electrical fire and follow your airplane's POH, which governs; the general pattern is this. Isolate the affected circuit first if you can identify it. If you can't, master switch OFF, alternator or generator OFF, and all other electrical switches OFF except the ignition. Never reset a circuit breaker that tripped. While the fire is active, close the vents, cabin air and heat, and use the fire extinguisher if you have one; ventilate only after you've confirmed the fire is out. With the master off, the engine keeps running on its magnetos, but you lose the radios and transponder, and often electric flaps and gear. So declare the emergency before the master goes off if you can, plan on the emergency gear extension, and be ready for a no-flap approach. Fire in flight is time critical: start an emergency descent and land as soon as possible at the best suitable site you can reach. Pick it early and judge it: over forest, an open field, or a road only if it's clear of wires and traffic and long enough. After landing, the ELT and survival gear matter, so know where they are.

AFH (FAA-H-8083-3C), Emergency Procedures; PHAK (FAA-H-8083-25C), Aircraft Systems

Brings together: Emergency Descent · Emergency Approach and Landing (Simulated) · Systems and Equipment Malfunctions · Emergency Equipment and Survival Gear

Teaching this? The instructor lesson plan →

Study aid, not FAA guidance. Sources: Airplane Flying Handbook (FAA-H-8083-3C); Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C); Aeronautical Information Manual (AIM); 14 CFR Part 91; Commercial Pilot ACS (FAA-S-ACS-7B); Your airplane's POH/AFM. Checked against current sources 2026-11-13.