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.
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!
FLY
SAFE!
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