Training and Safety Tip: Never take performance for granted

Just because the book says it can be done, doesn’t mean that you can do it. Your flight instructor might not be able to do it, either. Or even Capt. Chesley “Sully” Sullenberger—in this airplane, on this day, on this runway.

Here are some things I’d like you to consider: Is your mighty steed still putting out maximum rated power, or has it lost some of its oomph since its youth? When you plugged in your weight, did you count your clothing? Is the aircraft's empty weight up to date? Is your mixture setting dead on, or might it be a hair off? How clean is the air filter? Is the nosewheel tire pressure where it should be or two pounds low? Are the wings waxed and squeaky clean, or are there drag-inducing bug carcasses littering the leading edges? Is your runway rougher than the factory strip?

None of these things make much of a difference in and of themselves, but collectively they make up enough pinpricks to qualify as a pack of porcupines!

Frustrating, isn't it? You might wonder, why do the calculations in the first place? Because it’s a place to start, and it beats every takeoff and landing being a complete mystery. And because it’s the law. Literally. Check out your much tabbed-and-highlighted FAR/AIM. Right there in black and white at FAR 91.103(b), it says that for any flight, you need to run the numbers first.

The solution? Compare the expected numbers from your trainer’s POH with your actual experience on takeoffs and landings, and then—going forward—add a personal minimum above and beyond those observations to serve as an additional safety buffer. Choose a percentage, rather than a number of feet, so that it’s scalable. And like all personal minimums, reevaluate and readjust your numbers as you gain experience and skill.