Acknowledgements: Thomas P. Turner (Mastery Flight Training Inc.)

Taking off is one of the easiest things to do in an airplane. Most student pilots think they make the first take-off on their very first flying lesson: add the power, pull back a little on the stick, maybe depress the rudder pedals a bit one way or the other to stay more or less aligned with the runway, and off it goes! Of course, the flight instructor is very actively monitoring this process, subtly adding the correct amount of rudder and ensuring the elevator position and airspeed are within an acceptable range!

Making the first take-off, albeit with a lot of covert help, is a tremendously effective confidence booster for the nascent pilot. It provides a feeling of control that sets the tone for the student’s initial phase of training. But unless the instructor comes back after a lesson or two to point out all the factors that go into making a successful take-off, that’s not enough.

Yes, taking off is easy.
Taking off well, with mastery over a predictable outcome, takes a little more effort. Getting off the ground is only the first part of taking off. Once we’re in the air, we need to be able to climb. Most of us, however, do have the data we need to develop an expectation of take-off performance.

One of the most common things I find myself having to review in detail when providing recurrent training is how to make Take-off Distance and Obstacle Clearance Distance calculations. It seems to be a skill that deteriorates rapidly after passing that last Practical Test. Many pilots - even experienced ones - seem to need remedial training on how to make performance calculations and the pilot techniques necessary to attain calculated performance.

It’s not that pilots don’t know how to predict take-off performance, or at least that they never knew how, because at least once in their lives they had to prove that ability…on the “Knowledge Test” for their first pilot certificate. I think it’s more that almost all of the time we operate from airports where there is so much extra runway available that we don’t think we need to have at least a good idea how much runway we need, and how much distance it will take to clear that mythical FAA 50-foot obstacle. I know I went for a very long time without putting much thought into the take-off and obstacle clearance distances that apply for this take-off, under these circumstances, on this day.

Do you Remember how to interpolate? Recall how to apply corrections for headwind or tailwind component, or for operating off a dry, grass runway? Do you know the correct airspeeds, flap setting and take-off technique to obtain computed performance? I bet there was a time in your life when you did

We are fortunate that today there are computer-based solutions for take-off (and landing) performance. I’ve been using one now for the airplanes I most commonly fly. Before I trusted its programming, however (and every time the software provider posts an update), I did/do a few calculations by hand, using the POH charts and under a varied set of airplane weights and environmental conditions, to validate the software’s programming. I’ve found errors in some programs I’ve evaluated over the years, usually (I suspect) because the programmers were not aware of the myriad differences in speeds and performance of individual variations from year to year within a long-lived series of aircraft sharing the same model designation or name.

It’s our job to
ensure the software results match the POH data. Only then can we replace hand calculations with handy computer shortcuts.

So, when was the last time you made a Take-off Distance and Obstacle Clearance Distance calculations before you took off? Do you know the airspeeds for optimal performance in the airplane you’re flying, under the aircraft and environmental conditions that exist at the time? How do you compare actual, observed performance during your take-off and initial climb to calculated expectations? How do you respond to discrepancies between what you expect and what you actually see during your take-off and initial climb?

Taking off - it’s more involved than we think!

Tony BirthComment