Commercial pilot · ACS CA.II.F
Before Takeoff Check
The before-takeoff check confirms the airplane is ready and that you have a plan, including for the failure you hope never comes.
Why this one matters
The run-up is the last chance to find a problem on the ground, and the takeoff briefing is the decision you won't have time to make later. In a heavier, faster complex airplane, with passengers aboard, both carry more weight.
Can’t miss
- •Run the before-takeoff checklist by the POH, and know what each item tells you about the airplane.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Magneto check: the RPM drop on each, and the difference between them, within the POH limits, with smooth running. An excessive drop or roughness, too large a difference, or no drop at all (a magneto not grounding) means don't fly.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Constant-speed propeller: cycle it at the run-up RPM per the POH to check the governor and circulate warm oil to the hub.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Complex Airplanes)
- •Review takeoff performance for the runway in use; re-check it if the runway changes.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S1)
- •Divide attention: eyes outside during the run-up, brakes firmly held.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S4)
- •Brief the takeoff: speeds, an abort point, and the plan for an engine failure on the runway, at low altitude and higher up.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Departing behind a larger airplane: note its rotation point, rotate before it, climb above its path until you turn clear of its wake, and avoid headings that cross below and behind it; or wait (at least 2 minutes).(AIM, Chapter 7, Wake Turbulence)
What you should know
What the checklist is checking K1
- Run-up at the POH RPM: magnetos, carburetor heat or alternate air, oil temperature and pressure, suction, ammeter or load meter.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Propeller: at the POH run-up RPM, pull the control back: RPM drops, manifold pressure rises, and oil pressure dips briefly; push it forward and all three recover. No RPM drop means it isn't governing: don't fly.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Complex Airplanes)
- Flight controls free and correct; flaps and trim set for takeoff; fuel selector, boost pump and mixture set per the POH (leaned for density altitude if specified).(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Instruments and avionics set: altimeter, heading indicator, frequencies, transponder, flight plan in the GPS.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Doors and windows latched, belts and harnesses fastened, passengers briefed for the sterile departure.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
Attention and runway changes R1 · R2
- Position for the run-up on a firm surface free of debris, clear of other aircraft, people, vessels and buildings, with the propeller blast pointed at nothing it could damage, headed as nearly into the wind as possible (for cooling and stability); roll forward a little after stopping so the nosewheel is straight.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S3; Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Look outside often during the run-up: the airplane can creep and traffic moves around you.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S4)
- If ATC changes the runway, re-check takeoff distance and the departure, and say "unable" if it doesn't work.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
Wake turbulence R3
- Vortices are strongest behind heavy, clean, slow airplanes; they sink and drift with the wind.(AIM, Chapter 7, Wake Turbulence)
- Behind a departing larger airplane, all of these: note its rotation point, rotate before it, climb above its climb path until you can turn clear of its wake, and avoid later headings that cross below and behind it. Otherwise wait.(AIM, Chapter 7, Wake Turbulence)
Planning for a failure R4
- Brief two abort triggers: not at the briefed speed by the briefed point (set from runway length, surface, density altitude and obstacles); and any engine failure, abnormal indication or other malfunction anywhere in the roll before liftoff. Either one: throttle idle, brakes, stop straight ahead.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Engine failure on the runway: power to idle, brakes, and stop straight ahead.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Engine failure after liftoff at low altitude: lower the nose to hold glide speed and land ahead or within small turns. In a retractable, gear and flaps per the POH for the landing.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- A turn back needs much more than 180° (about 225° to line up again) and often ends in a downwind landing. Know your airplane's real altitude loss from practicing at a safe altitude (one AFH example lost about 1,300 feet); never brief a guessed round number. Below it, land ahead.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
On the flight
ACS standards
- Review takeoff performance; complete the checklists; position the airplane for wind and nearby aircraft, vessels or buildings.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S1-S3)
- Divide attention inside and outside; verify engine parameters and configuration are suitable.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.F.S4-S5)
What your instructor is watching for
Your instructor watches for a checklist-driven run-up including the propeller check, eyes outside, correct interpretation of the magneto and propeller checks, and a clear takeoff briefing with an abort point and engine-failure plan.
Scenarios
Decide what you would do first, then see the worked answer.
On the propeller check, the RPM doesn't drop when you pull the propeller control back.
What do you do? See the worked answer
Don't take off; the governor or control may not be working. Taxi back and have it checked.
Airplane Flying Handbook (FAA-H-8083-3C), Transition to Complex Airplanes
A regional jet just departed from your runway.
How do you plan the takeoff? See the worked answer
Ask for at least 2 minutes (ATC must apply it behind a heavy or a 757, which you can't waive; behind other large aircraft you request it). Even with a takeoff clearance, wake avoidance is yours: rotate before its rotation point and climb above its path. Vortices linger longest in light quartering tailwinds.
AIM, Chapter 7, Wake Turbulence
At your abort point you're 10 knots below the speed you briefed.
What do you do? See the worked answer
Abort: power to idle, brakes, stop straight ahead. Then find out why: density altitude, a dragging brake, or an engine problem.
Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations
Common mistakes
Skipping the propeller cycle or doing it too quickly.
A governor fault is found on the ground or in flight.
Instead: Cycle it per the POH and watch RPM and oil pressure respond.
A takeoff briefing without an abort point.
Without one, a slow acceleration is noticed too late.
Instead: Brief an abort point and speed every time.
Accepting a runway change without checking performance.
The new runway may not work today.
Instead: Re-check, then accept or say "unable".
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice before takeoff check out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Airplane Flying Handbook (FAA-H-8083-3C): Ground Operations; Transition to Complex Airplanes
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C)
- Risk Management Handbook (FAA-H-8083-2A)
- Commercial Pilot ACS (FAA-S-ACS-7B): Area II
- Your airplane's POH/AFM: normal procedures and checklists
- AIM: Chapter 7, Wake Turbulence
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.