Flying by the Numbers

Days ago, I was observing how my junior First Officer was fighting to keep attitude, altitude, heading and airspeed where they were supposed to be meanwhile we were in a course to intercept the localizer. In the meantime I was telling him:  – Good, Fly the numbers!

As pilots, every time we fly a new aircraft or, “equipment”, as is called by the airlines, we are told memorize hundreds of numbers, speeds, power, trust settings, pitch degrees, limitations, etc., but numbers also give us patterns and patterns is what we must follow if we want to notice that something is not right or in the place is supposed to be.

Numbers give us borders, as an example, the concept of a stabilized approach is based on having a certain speed and configuration at a certain altitude during approach if, for some reason this pattern is not achieved, a go around is mandatory.Untitled

Patterns for complex aircraft and airliners are established on the AOM – Aircraft’s Operator Manual, but we can also develop a pattern for our small GA airplane based on data extracted from the POH – Pilot’s Operating Handbook and develop our own pattern or “numbers” for takeoff, climb, approach and landing.  You can start experimenting by yourself noting what power setting gives you a certain speed in level flight, let’s say 100 knots and, if you add flaps? – Then, to maintain same speed with a flap deflection you will need a higher power setting.  Next can be, 360 degrees steep turns? – in clean configuration, level flight, establish your airplane in a certain heading, speed and power and note it, by reference to the ADI – Attitude Director Indicator or Artificial Horizon, bank your airplane in a 45 degrees angle to either side and increase the power by about 5% to the setting required to maintain wings level. Pull on the control yoke as you roll in to counteract for the push down force, instead of chasing the Vertical Speed Indicator pull up to a certain degrees of pitch that gives you a zero on the VSI.  See? You have a certain power setting, you are maintaining speed and you have certain degrees of pitch to maintain level turn. Approach and landing – don’t simply extend flaps when your airspeed indicator shows white arc, define a “speed threshold” for each flap setting.  The POH for the 2001 Cessna 182S shows a Vso at maximum takeoff weight of 50 knots, when multiplied by 1,3 as a result we obtain a Vref of 65 KCAS or 61 KIAS, adding a correction of 10 knots we get an approach speed of 70 knots KIAS.  Use this speed in still air, with full flaps, if windy conditions we have to add a correction for gusts. (add to Vref half of the headwind component plus the gust).  See? We are already flying by the numbers.

Always remember, power plus pitch attitude equals performance

Flying by numbers give us an envelope, learn to respect and follow them should be part of our culture


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