Commercial pilot · ACS CA.I.F
Performance and Limitations (Commercial)
This lesson covers how to use performance charts, what changes performance, the aerodynamics behind it, and the limitations you never exceed.
Why this one matters
Commercial pilots fly heavier, faster airplanes with paying passengers and their bags, often from unfamiliar runways. Most performance accidents come from trusting the book number without margin, or loading the airplane past a limit because the runway looked long enough. Knowing the gap between calculated and actual performance is the protection.
Can’t miss
- •Use the POH charts for takeoff, climb, cruise, landing and weight and balance. Read every note: wind, slope, surface and technique corrections.(Your airplane's POH/AFM)
- •Density altitude is pressure altitude corrected for nonstandard temperature; humidity raises it a little more. Thinner air means less lift, less engine power and less propeller thrust: longer takeoff, weaker climb, and a higher true airspeed and groundspeed for the same indicated.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- •Book numbers come from a new airplane in good condition, flown with average piloting skill in normal conditions. After every POH correction, many pilots add their own margin (a common rule of thumb is 50%) to takeoff and landing; it is a personal rule, not an FAA requirement.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- •Weight and center of gravity are separate limits. An aft CG reduces stability and stall/spin recovery; a forward CG raises stall speed and needs more elevator.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- •Maneuvering speed (VA) protects against one full, abrupt deflection of one control in one axis, not combined, repeated or reversing inputs, and not every gust. It falls with weight: VA × √(actual weight ÷ gross weight), or the POH table.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight)
- •Load factor increases in turns: 60° of bank is 2 G, and stall speed rises by about 41%.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight)
- •Never exceed a limitation in the POH/AFM: speeds, weights, CG range, load factors.(14 CFR 91.9)
What you should know
Charts and data K1 · R1
- Charts come as tables and graphs. Interpolate between lines, never extrapolate past them, and read the conditions they assume: weight, flaps, paved dry runway, technique.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- A graph, in order: enter at the outside air temperature, go up to the pressure altitude line, across to the reference line, follow the guide lines for weight, then for wind, then read the distance; apply the notes for surface and slope last.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- 91.103 makes this a duty: before every flight, know the runway lengths and the takeoff and landing distances for the expected conditions.(14 CFR 91.103(b))
- Compute takeoff and landing distances over a 50-foot obstacle, not just ground roll, when obstacles are near.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
What changes performance K2 · R3
- Atmosphere: density altitude (altitude, temperature, humidity). Runway: slope, surface (grass, wet), wind.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- Configuration: the POH flap setting and gear position for each phase. Landing traps: more flaps than the chart assumes changes the numbers, and a fast or long approach can double the landing distance.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance; Airplane Flying Handbook (FAA-H-8083-3C))
- Pilot technique: speeds, configuration and timing make a big difference in short-field performance.(Airplane Flying Handbook (FAA-H-8083-3C))
- Loading: weight increases takeoff distance and stall speed; CG location changes stability and control.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
- Expect actual performance to be worse than the book: a worn engine, a dirty airplane, soft ground. Add a margin and set an abort point.(Airplane Flying Handbook (FAA-H-8083-3C))
Aerodynamics K3
- A wing stalls at its critical angle of attack, at any airspeed or attitude. Load factor raises the speed at which it happens.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight)
- Turns, pull-ups and turbulence increase load factor. Limit load factors, flaps up: normal category +3.8 and -1.52 G; utility +4.4 and -1.76 G; acrobatic +6.0 and -3.0 G. With flaps extended the limits are lower.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight)
- VA = stall speed × √(limit load factor), so it falls when weight lowers the stall speed. In turbulence, fly at or below the POH turbulence-penetration speed (often near VA for your weight).(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight)
Limitations R2
- The POH/AFM Limitations section (speeds, weights, CG range, load factors, kinds of operation) is the law for that airplane.(14 CFR 91.9)
- Weight and balance: weight × arm = moment for each item; CG = total moment ÷ total weight. Check it on the envelope for takeoff and for landing (or zero fuel), since burning fuel moves the CG.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Weight and Balance; Aircraft Weight and Balance Handbook (FAA-H-8083-1))
- Bags and passengers move the CG. Compute weight and balance for every flight with real weights.(Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance)
Scenarios
Decide what you would do first, then see the worked answer.
Your passengers’ bags push the CG half an inch behind the aft limit, though you’re under max weight.
Do you go? See the worked answer
No. Move or remove the bags until the CG is within limits.
Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aircraft Performance
Your takeoff roll is passing the point where you expected to be airborne.
What should you have planned? See the worked answer
An abort point (for example, 70% of takeoff speed by half the runway), and abort if you aren’t there.
Airplane Flying Handbook (FAA-H-8083-3C)
Turbulence en route, and you’re light with one passenger.
What speed do you fly? See the worked answer
Below the maneuvering speed for your current weight, which is lower than at gross.
Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Aerodynamics of Flight
Common mistakes
Using book numbers without margin.
Real airplanes and pilots do worse.
Instead: Add a margin and set an abort point.
Guessing passenger and bag weights.
The CG can end up out of limits.
Instead: Ask or weigh, and compute.
Treating weight and CG as one limit.
Under gross can still be out of CG.
Instead: Check both every time.
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 performance and limitations (commercial) out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C): Aerodynamics; aircraft performance; weight and balance
- Airplane Flying Handbook (FAA-H-8083-3C)
- 14 CFR: 91.9
- Commercial Pilot ACS (FAA-S-ACS-7B): Area I, Task F
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.