Centerline
7 min read

Arcane as the word sounds, “proficiency” is a metric of consistency. The recency of experience holds more than the promise of a glorious past experience. Take those words for their worth. They matter! They matter in business, in marketing, in promoting, in medicine, in manufacturing, in the practiced showmanship in law, in engineering, in aviation and all other disciplines where experience is charted on the “X” axis as time.

What does the promise of proficiency hold in its bag of goodies, one might ask? A lot, it seems. In aviation where this theme is constantly explored, one sees a myriad of ways where proficiency can and does lead to safety. And safety is the paramount word in an inherently difficult “Z” axis when the third dimension of space comes into play—where we fly.

I remember taxiing with an instructor a while ago when he applied the brakes deliberately to my, “What the…?”

“Why,” I asked, “would you do that?”

Centerline

Learn to love that centerline.

His face slightly and perhaps through years of experience expertly contorted to make the scene somber, and he asked, “Where is the aircraft located in relation to the centerline?”

“Umm, well…”

No there were no further words that would satisfy that question. Indeed, where was the aircraft that I commanded from the left seat in relation to the taxiway centerline? It was almost two feet left of it! A gross outlier in the scheme of things! Even today after many years, I find myself drifting every so slightly left and right of the centerline and those words haunt me. The other day, a friend with many thousand hours in large aluminum bodies remarked, “Keep the centerline under your right foot/rudder.” Hmm, gentle rebuke but with a smiley face, that was. It has now become an obsession with me to look at the far end of the runway and gently dance on the rudders to keep me and the aircraft honest. The hard work continues even after close to 5000 hours of flight.

But you might ask, why is that important? The answer might strain and delight you simultaneously. Strain you, because, well, you have been told that is the way to go and delight you that someone else has similar issues. But let me delve into the nuances of this seemingly innocuous bad habit. The centerline exists for the simple reason of maintaining control of the aircraft and staying away from the taxi lights and other natural wonders, such as snow drifts. One such meeting of the aluminum and the snow drift exacts a larger premium from the insurance company.

Then there is this centerline need during takeoff and landing as well. On a 100 or 200-foot wide runway, it may seem silly to concentrate on the centerline because, well, there is ample distance between the winglets/tip-tanks and the runway edge. But bad habits started there can lead to some awful scenarios. Take, for example, landing on a 2500-foot runway which is 50-feet wide. Now a view from the cockpit of our favorite Beechcraft will show the wings seem to overhang the runway edges. Also, some of these hundreds (if not thousands) of runways scattered over the nation don’t have centerline markers.  Perhaps time has erased such a material memory, or one was never there from the beginning. Now lay that scene out a bit and add a crosswind component testing the limits of the rudder authority, and you have the makings of an expensive financial and potentially heavenly excursion, off the tarmac.

But there is more to that maintaining the centerline concept than meets the eye. Staying true to this dictum teaches you some degree of precision, and perhaps some degree of apprehension, to keep your wits properly entuned to the rigors of good airmanship and safety. Such concentration bleeds into other aspects of flying as well. It makes for a better aviator. You concentrate on preventing lapses in holding headings and altitudes when the autopilot gives up the ghost due to a $10 resistor going bad. It forces the pilot to concentrate on every aspect of safety by flying the aircraft as proficiently as possible. There is that “proficient” word again. Practice good habits often and practice them with zeal.

The Six Pack instruments

Fly by the numbers and you may find your landings get better.

Let us say you are landing. What things do you unconsciously do to arrive at the runway? There is the power setting, the configuration of the aircraft and its attitude. If you have marveled at the reasons some pilots fly the aircraft without any tremors and clenching and unclenching of the teeth or whitish knuckles with the yank and bank method, then let me fill you in on their secret (you probably already know this). They usually fly “by the numbers!”

What does “fly by the numbers” mean? Simply put as, pilot you input the three categories:

  1. Power (Manifold Pressure and RPM) or just RPM as the case may be
  2. Configuration of gear (down if not welded) and flaps
  3. Attitude 3-5 degrees above the horizon as specified in your POH

And you will get a consistent aircraft performance. Perhaps in a Bonanza a 17 inch/2400RPM/gear down/3 degrees nose-up gets you a 500-600 foot per minute rate of descent… perfect for a precision approach and for a nice visual approach to landing. Add the full flaps and lower the power setting to 14 inches of MP and now you have 80 knots of airspeed on final for a smooth touch down on the numbers. Other aircraft have their own PAC (power, attitude, configuration) settings for their expected performance. So, eliminating that approach guesswork frees the brain for more precision as you are readying for the flare and impressing your passengers with the chirp.

Here is where it gets a bit interesting. Subconsciously you have been making all the necessary adjustments to your flight path in order to land on the runway. This occurs on final approach to the runway at whatever altitude you are at. Small left and right 2-3 degree changes are subconsciously happening due to changes in wind speed from the terrain friction (Coriolis effect), as you descend to your destination. The descent is aborted and level flight occurs 3-5 feet over the runway to bleed off excess speed, and the aircraft is readied for the flared landing.

Right about then a relaxation of sorts sets in the synapses of your brain. “Ah, I have arrived.” Hmm, not yet friend, not yet, says precision, while precision’s ugly brother sings his happy tune. That demon lets you plop the wheels anywhere they will involuntarily touchdown. The result is a slight drift left or right, because of a heavy left hand, a crosswind, or other distraction inside and outside the cockpit, which might have assailed your sense of control.

What to do? All is not lost—even at 3-5 feet over the runway. You can gently nudge the aircraft to the centerline by using a gentle side slip. Bank 2-3 degrees towards the centerline and use opposite rudder to control the drift and maintain the aircraft pointed to the departure end of the runway. Once back over the centerline, release the pressures of the bank and the yaw. Voila, you have arrived! Precision is in play again! Now concentrate on the far end of the runway and maintain centerline gently with minimal rudder inputs.

The flight is still not over though. Exiting the runway, make a habit of using the yellow markings to stay centered on the taxiway exit and once past the hold short line, then—and only then—make any adjustments to the aircraft configuration (flaps, cowl flaps, etc.). At night, the yellow markings are a great asset in exiting the runway at the right taxiway and not onto the unpaved area.

Proficiency is a story of safety through constant practice, of acquiring experiences and then putting these experiences to hatch their possibilities. These experiences, however, must be taught to the “habit monster” within us to have the element of precision baked into them. All other non-precise experiences are side shows and fodder for the evening news of disasters where one asks the question, “Why did he do that?”

Parvez Dara
Latest posts by Parvez Dara (see all)
7 replies
  1. Mark Sletten
    Mark Sletten says:

    The term “normalization of deviance,” coined by sociologist Diane Vaughan when reviewing the Challenger disaster, describes what happens when you neglect the small stuff. If you keep doing things wrong and getting away with it then you reinforce the bad behavior.

    “Eh, I’m off centerline a few feet, but the taxiway is wide, and I need to copy this ATIS before I get to the runup, so…”

    The first core value of the US Air Force is “integrity first.” It’s defined as a willingness to do what is right even when no one else is looking. It means YOU are your own evaluator and executive; YOU set the standard; YOU enforce it. If you apply this principle correctly and consistently then a checkride shouldn’t be a particularly stressful event, because even if you do make a mistake no evaluator will be as tough on you as you are on yourself.

    Reply
  2. David Ward Sandidge
    David Ward Sandidge says:

    Interesting article. Lot’s of good stuff. Thank you for writing it. One additional item may help: In a substantial to very strong crosswind landing while crabbing down the final approach path, it may help to “put” (align) the tail of the airplane (or something behind you on the airplane) onto the extended runway centerline so that you, the pilot are sitting slightly upwind of the centerline – slightly to the left or right of the center of the runway. That way, when you kick the rudder and lower the upwind wing during the flare you won’t suddenly and unexpectedly be blown so far off the centerline. We use this method often in airline operations. In strong direct crosswinds (up to 35kts), the B757 lands just like a Cessna 172 – upwind wheel set touchdown first with lots of downwind rudder to keep the longitudinal axis aligned with the runway, and substantial aileron into the wind to maintain drift correction. And all the way down the final approach path I’m sitting just a little upwind of the extended centerline. I use the same method for practically all the different airplanes I fly. I was forced to use it to the extreme one time while landing a short winged Swearingen airliner in a sustained 50 knots, 90 degrees crosswind. (Not recommended except in an emergency – which it was…) The airspeeds one would use for these ridiculous crosswind conditions are for another forum. And I’ll let you discuss those if you wish.

    Reply
  3. Enderson Rafael
    Enderson Rafael says:

    Perfect! It becomes a habit, that will make a big difference if you ever transition to the big jets. In the airlines, nothing less than center line is expected from you. When all GA pilots understand that you’ve got to fly professionally even when flying for yourself, GA safety records will go sharply up. Operational discipline is everything, and this center line thing might sound silly at first, but is the base of a long process. Remembers me of the “make your bed” speech: if you can’t do the small things right, you will not be able to do the great things right.

    Reply
  4. Frank
    Frank says:

    I would keep telling my students (for example) great it was a nice landing except you seem to consistently land 4 feet off center. If you can do that so consistently why not try to target the center? The same goes for flying a precise altitude rather than accept being 150 feet off, and so on. If you can fly with accuracy, why not fly with precision?

    Reply
  5. Charles Lloyd
    Charles Lloyd says:

    As a Citation sales rep I’m year gone by, the demo pilots allowed me to fly some of the positioning flights. In a Citation II flying a visual approach in South Texas, I made a squeaker landing to the left of the center line. Between the seats Dick, the demo pilot, responded in a proper gravelly voice, “Congratulations on a fine landing on the left half of the runway. How using the centerline next time,”

    I never use only half of the runway again.

    Lesson learned

    Reply
  6. Joel Godston
    Joel Godston says:

    Parvez, your “Fly by the Numbers”, three categories that I call, PCA, is ‘Right On’; and what I used during my 50+ years of flying the Piper Cub, T-28, T-33, and B-47 aircraft in the US Air Force; T-33, F-84, and F-86H in the Mass. ANG; and a Cessna 182 aircraft that we (my wife Annemarie and I) owned and flew in the civilian sector. However, the use of the centerline is not always what a pilot should line up on. For example, when I was flying in the US Air Force, Mass. ANG, and Cessna 182 in the civilian sector. the safe and proper thing to do was to be off the centerline to avoid/minimize jet or prop ‘wash’ from aircraft taxing, taking off, or landing in front of you. What do you think Parvez?

    Reply

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