Your POH performance charts turn today’s weather, weight, and runway into real numbers: exactly how much runway you need to lift off, how far you will roll on landing, and how well the airplane will climb. Reading them correctly is a matter of finding the right chart, entering it with pressure altitude and temperature, and never rounding in your favor.
Part of our Aircraft Performance guide.
What a POH is and where the performance charts live
The POH (Pilot’s Operating Handbook) is the manufacturer’s official manual for one specific airplane, and its performance section is where the takeoff, climb, cruise, and landing charts live. On older aircraft the same book is often titled the Pilot’s Information Manual or the Airplane Flight Manual (AFM), but the layout is the same. Section 5 (Performance) is where you will spend your planning time; Section 2 (Limitations) and Section 4 (Normal Procedures) tell you the conditions the charts assume.
Every performance chart is built on a set of associated conditions printed on or near it: a specific flap setting, full throttle applied before brake release, the mixture leaned per the POH, a paved level dry runway, and zero wind unless a wind correction is included. If your real conditions differ from those assumptions, your real numbers will be worse than the chart. Treat the chart as the best case, not the promise.
These charts are aircraft-specific, so you plan with the book for the exact make, model, and year you fly. PilotMall stocks factory-style aircraft POH and AFM reprints across the trainer fleet, including a full set of Cessna 172 and Skyhawk manuals, so you can practice chart work with the same numbers you will use on your checkride.
Ground roll vs total distance over a 50-foot obstacle
Every takeoff and landing chart gives you two distances, and the difference between them is one of the most important habits to build early. Ground roll is only the distance the wheels are on the pavement. Total distance over a 50-foot obstacle adds the air distance you cover while climbing to (or descending from) 50 feet above the runway.
- Ground roll: brake release to liftoff on takeoff, or touchdown to full stop on landing.
- Total distance to clear 50 ft: the same roll plus the horizontal distance to climb from liftoff to 50 feet (takeoff) or to descend from 50 feet to touchdown and stop (landing).
Always plan with the total distance over the 50-foot obstacle. The ground roll is a tempting smaller number, but it ignores the trees, fences, approach lights, and rising terrain that live off the end of most runways. If the total-distance figure does not fit your runway with margin, the ground-roll figure is irrelevant.
How to read a takeoff performance chart step by step
Most trainer takeoff charts are tables you enter with pressure altitude and temperature, then read across to your weight. Work them in a fixed order every time so you never skip the wind or obstacle correction.
- Find the correct chart and read its associated conditions (flap setting, throttle, mixture, and runway type). Confirm it is the takeoff chart for your airplane and configuration.
- Calculate your pressure altitude by setting the altimeter to 29.92 in Hg, or by using field elevation plus (29.92 minus the current altimeter setting) times 1,000.
- Get the outside air temperature (OAT) forecast for your departure time from the current METAR or TAF.
- Enter the chart at your pressure altitude row and your temperature column, then move to the block for your actual takeoff weight.
- Read both output numbers: the ground roll and the total distance to clear a 50-foot obstacle.
- Apply the wind correction printed on the chart, subtracting distance for a headwind and adding distance for a tailwind.
- Interpolate between the printed rows and columns rather than rounding to the nearest line in your favor.
- Add your personal safety margin, commonly 50 percent or more, before comparing the result to the runway length available.
You need three inputs before you touch the chart: pressure altitude, temperature, and weight. Pressure altitude comes from the pressure altitude calculation, temperature comes from the weather (see how to read METARs and TAFs), and weight comes from your weight and balance worksheet. Getting those three right is most of the job.
Interpolation: reading between the rows
Real conditions almost never land exactly on a printed line, so you interpolate to find the value in between. Interpolation is simple proportion: if your temperature is halfway between two columns, your distance is roughly halfway between the two printed distances. The one rule that matters is to never round in the direction that makes the runway look longer or the airplane look better.
Say the chart lists a ground roll of 800 feet at 20 C and 900 feet at 30 C, and the forecast is 25 C. Halfway between the temperatures means halfway between the distances, so you plan for about 850 feet. If you are between two altitude rows and two temperature columns at once, interpolate one variable, then the other. When you are unsure or the math is close, round toward the longer, more conservative distance. The chart already assumes a perfect airplane and a perfect pilot; interpolation is not the place to find optimism.
How weight, density altitude, wind, slope, and surface change your numbers
Five variables move your takeoff and landing distances, and every one of them can move them a lot. Enter the chart with them honestly.
| Factor | Effect on takeoff and landing distance |
|---|---|
| Higher weight | Longer ground roll and total distance; slower acceleration and a higher liftoff speed. |
| Higher density altitude (high, hot, humid) | Longer distances and weaker climb; the wing, engine, and propeller all produce less. |
| Headwind | Shorter takeoff and landing distance. |
| Tailwind | Longer takeoff and landing distance (avoid whenever possible). |
| Upslope runway | Longer takeoff roll; can shorten the landing roll but complicates the go-around. |
| Soft, grass, or contaminated surface | Longer takeoff roll from higher rolling resistance; braking and stopping affected on landing. |
Density altitude is the big one, because it silently combines altitude, temperature, and humidity into a single effective altitude the airplane actually feels. On a hot day at a high-elevation field, the airplane can perform as though the runway sits thousands of feet higher than its charted elevation. The full mechanism is covered on the density altitude page. Many POH charts fold temperature into the table for you, but you should still understand why the numbers grow: high density altitude reduces lift, engine power, and propeller thrust all at once.
Note that these charts give you the numbers only. The technique for short, soft, and obstacle work is a separate skill; see short and soft field takeoffs and landings and how to land an airplane for the flying part. The chart tells you whether the runway is long enough; your training tells you how to use it.
Climb performance: Vx vs Vy, rate of climb, and service ceiling
Once you are off the ground, climb performance decides whether you clear the obstacle and how fast you reach a safe altitude. Two speeds define it, and confusing them is a classic checkride miss.
| Vx (best angle) | Vy (best rate) | |
|---|---|---|
| Optimizes | Altitude gained per horizontal distance | Altitude gained per time |
| Use it for | Clearing an obstacle right after liftoff | A normal cruise climb once obstacles are behind you |
| Airspeed | Slower | Faster |
Vx is the best angle of climb: the steepest possible climb path, which is what you want when trees or wires sit off the departure end. Vy is the best rate of climb: the most altitude in the least time, which gets you to a safe maneuvering altitude quickly on a normal departure. As you climb, Vx increases and Vy decreases, and the two speeds converge. Where they meet, the airplane can no longer climb: that point is the absolute ceiling.
Two ceiling numbers describe how high the airplane can go. The service ceiling is the density altitude where the maximum rate of climb falls to 100 feet per minute; it is the practical top of useful performance. The absolute ceiling is the density altitude where the rate of climb reaches zero. Both are density altitude figures, which is why a hot, high day pushes the airplane’s real ceiling far below the published one. Your POH climb-performance charts give rate of climb and the time, fuel, and distance to climb for your weight, pressure altitude, and temperature; read them exactly like the takeoff chart, and remember that a weak climb rate is often the first sign that density altitude is working against you. A shallow, mushy climb is also a stall warning in disguise, so keep the connection to stalls in mind when performance is marginal.
Building a personal safety margin
POH numbers are best-case figures produced by a factory-new airplane flown by a professional test pilot under ideal conditions, so you must pad them before you trust them. The most common rule is to add at least 50 percent to the charted takeoff and landing distance, which is the same as multiplying the chart number by 1.5. Many cautious pilots use a factor of 1.5 to 2 depending on the airplane’s age, their own currency, and the stakes of the runway.
- Aging airframe and engine: a well-used trainer will not match test-pilot numbers, so pad more, not less.
- Your recency: if you have not flown a short or soft field lately, buy yourself extra runway.
- Consequences of the specific runway: a short strip with obstacles and no overrun deserves the biggest margin you can give it.
Turn the padded distance into a personal go/no-go number and honor it: if the required distance times your factor exceeds the runway available, you do not go. This same disciplined chart work belongs in your cross-country planning, and examiners expect you to talk through it on the oral exam. When you learn the electronic and manual flight computers on the E6B and CX-3 page, you will see how quickly they turn raw weather into the density altitude and true airspeed those charts assume.
What you'll need
The right manual and flight computer make chart work fast and accurate, all from PilotMall.com.
Frequently asked questions
What is a POH?
The POH (Pilot’s Operating Handbook) is the manufacturer’s official manual for a specific airplane, and its performance section holds the takeoff, climb, cruise, and landing charts you use for real-world planning. For older aircraft the equivalent book is often called the Pilot’s Information Manual or the Airplane Flight Manual (AFM).
What is the difference between ground roll and takeoff distance?
Ground roll is the distance the airplane rolls on the runway before the wheels leave the ground, while takeoff distance is the longer number that also includes the air distance needed to climb to 50 feet. Always plan with the total distance over the 50-foot obstacle, not the shorter ground roll.
Why do POH charts use a 50-foot obstacle?
POH charts use a standard 50-foot obstacle because it represents the trees, fences, or lights near a typical runway end and gives every airplane a consistent, comparable way to measure real takeoff and landing distance. The 50-foot number is always longer than the ground roll, so it is the safer figure to plan with.
What is the difference between Vx and Vy?
Vx is the best angle of climb speed, giving you the most altitude gained per unit of horizontal distance, so you use it to clear an obstacle right after takeoff. Vy is the best rate of climb speed, giving you the most altitude gained per unit of time, so you use it for a normal cruise climb once obstacles are behind you.
How much safety margin should I add to POH distances?
Add a personal safety margin of at least 50 percent to the POH takeoff and landing distances, because the book numbers assume a brand-new airplane, a professional test pilot, and perfect technique. Many pilots use a factor of 1.5 to 2 times the chart distance and will not use a runway that does not meet that padded requirement.