In recent years, the problem has been exacerbated. It used to be that pilots and controllers communicated in a fairly simple fashion, resorting to plain language when it suited. I recall attempting to affect an airline captain’s “Ah’, roger” drawl after obtaining my commercial certificate 60-odd years ago. Maybe I threw in a “Wilco” once in a while, signifying “will comply.” Instructions and requests were traded in a relatively clear manner.

We called ground control with an “On the ramp, ready to taxi” and got a terse “Taxi to one-eight.” If we wanted help finding our way, we could ask, otherwise, it was expected that we knew where the runway was and would call the tower for takeoff in due course. The frequency remained relatively uncongested. 

But pilots botched up from time to time, blundering into blind-alley taxiways or heading across an active runway. So taxi instructions gradually got more complex and wordy, first with a mandate to read back all “hold short” instructions and then with specific designations for a full-route clearance, all to be repeated verbatim. 

“Taxi to one-eight” became “Taxi to Runway 18 via Juliet, Alpha, and Romeo, hold short of Runway 31, confirm you have information Delta.” We soon learned we could get away with parroting “Taxi 18, Juliet/Alpha/Romeo, hold short 31, we have Delta.” 

Back in the beginning, we simply acknowledged receipt of a clearance by replying with our N-number, clipped to the last three ciphers if the tower had so stated it, just enough to assure that the right airplane heard the word from above. In all cases, the conversation was being recorded, and confirmation was important in the event of an investigation.

At this point, the controller’s manual requires controllers to state so many more advisory reminders, much of which we dutifully repeat back, that the frequency is filled with rapid-fire, nearly unintelligible verbiage, filed away in our mental cavities but not truly listened to. But, duty must be done.

The danger is that habitual repetition leads to hearing what we expect to hear, not what was truly said. 

“Cleared for the visual, report three mile left base for Runway 31,” becomes “Cleared to land, 31” in our mind, even though we read back the visual and report instructions. Or, as in the case of the Hawker crew at Houston recently, “Line up and wait” was interpreted as “Cleared for takeoff,” leading them to clip the tail of a cross-landing Citation. The old pre-ICAO “Position and hold” instruction was much more declarative, in my humble opinion.

My associates and I are now given to speaking slower, at the risk of overstaying our welcome on frequency, in hopes that ATC will reciprocate in intelligible delivery. Even so, well-meaning imposition of advisories and southern-exposure protections burden controllers with so much “New Speak” that we long for the days of shorter communication.

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The pilot asking was experienced enough to plan a trip thoroughly but was still learning with every new encounter. Because he wasn’t sure of the significance of “WS020/32020KT” in the Terminal Aerodrome Forecast, he wanted me to give him an up-or-down judgment about going.

Ordinarily, I avoid playing dispatcher when I haven’t been “plugged in” to the weather situation. But I did know a front was moving in, and the time of day was conducive to temperature inversion. Those two factors logically gave rise to the likelihood of low-level wind shear, so I spoke to that effect on his trip. He opted not to go out of an abundance of caution.

For light aircraft, a wind shear note in a TAF is not necessarily a hazardous warning, but a flag that means something is out there, requiring us to be ready to deal with it. It shouldn’t be confused with wind shear alerts generated by LLWAS systems at major airports, which indicate serious, real-time threats. Airliners are maxed out on spare performance capability when taking off and landing, so a loss of airspeed due to a wind shear encounter can be life-threatening.

Piston-engine airplanes flying through changing wind conditions can cope with turbulence and airspeed fluctuations using throttle jockeying and pitch-attitude adjustments. That’s why we fly our approaches at 1.3 VS0 as a speed reference, with half the reported gust spread tacked on for safety, and we’ll lift off and climb out faster in rough air.

So, what’s the issue with those “WS” forecasts? They are telling us there’s a possibility of a change into the noted wind direction and speed at or below the height shown–2000 feet AGL in the opening paragraph. It can be from a frontal passage when the surface wind shifts and the low-level atmosphere gets stirred up by the change. You may take off to the south, then suddenly find yourself battling a northerly wind as you climb out on course. Hopefully, you’ve considered this wind change in your fuel planning.

Any turbulence encountered in the wind shear will generally be short-lived unless your flight profile calls for staying low or there’s perpendicular-oriented terrain upstream. As you climb out, your GPS track will notably shift, requiring a heading change, but the ride will smooth up. In the absence of hills, the rough air comes from the point at which two layers of air are moving in different directions, giving us some piloting to do as we climb or descend through the friction level. 

We used to hear of “low-level jet streams” encountered on clear, cool nights with calm air at the surface. We would find them during climbout, the airplane suddenly bucking and bouncing and then calming down as altitude increased, but with the ground lights moving sideways. I’ve seen 40 knots of wind at 3000 feet AGL, as the cold surface air layer provided a slick cushion for the flow of warm air aloft moving across it. Once up into the inversion, there would be no turbulence, just a massive heading correction.

Therefore, we need to pay attention to the TAF wind-shear notation because it means changes are afoot, but in the absence of other indications, it’s not a reason to scrub a trip. Just be prepared.

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