March 2012
Over the past 50-plus years of being involved with airplanes, I’ve had a number of memorable bouts with turbulence. When I count the episodes that come to mind, you might be surprised to discover that those that occurred in large airplanes outnumber the light aircraft incidents by a significant margin. This imbalance makes immediate sense because I’ve got a great deal more hourly exposure in transport-category airplanes than in General Aviation singles and light twins. But the hours alone are not the only reason.
Here are the other factors that have made my turbulence stories come more from the airline-flying category: first and foremost, when I’m faced with a long and bumpy trip in a light airplane, I can often find a reason to do something else that day. Not so with the airline; they wanted me to go anyway.
Also, the nature of jet travel puts us across lots of altitudes and lots of air masses—some of them rubbing quite aggressively against their neighbors—while an all-day ride in my personal airplane often deals with no more than two separate weather arenas. For General Aviation trips under three hours, it’s not uncommon to be steadfastly in the grips of the same designated air mass the entire journey, and that makes the likelihood of big changes in the atmosphere—the generating force for really good examples of bad turbulence—less prevalent.
But not always. One General Aviation trip that stands out in my mind occurred on a relatively long flight in a light twin. I was headed from Florida to New York, with one en route fuel-and-facilities stop in the Washington, D.C. area. A big nor’easter was off the New Jersey coast, and a deep low was pumping scads of moisture inland. By the time we were shooting the overcast-and-rain instrument approach at Washington, we could see that the forecast was accurate and a good amount of heavy weather lay ahead. For reasons that escape me now, we elected to continue on to White Plains.
By the time I reached cruise altitude for the final leg to New York, we were rocking and rolling as we plodded ahead through the moisture-laden clouds. Altitude selection was academic, because everyone on the frequency was complaining about moderate or more at every conceivable level. I hung in at 7,000 feet, and finally gave up on the autopilot as it was more of an aggravation than a help—although I did punch it on periodically so I could peek at a chart or dial in a frequency.
The turbulence was relentless but manageable, which translates into keeping the bottom of the wings pointed earthward with the nose more or less in the direction of my intentions.
What stands out in my memory, though, was the approach itself: an ILS into White Plains that came with a 40-knot crosswind that was 60 degrees to the runway—far stronger and heavier a crosswind than forecast. It caused enough panel gyrations to make just reading the dials an invigorating challenge.
To top it all off, the ceiling was reported as 300 feet—which I verified when the runway finally appeared at two o’clock, low, thanks to the enormous crab needed to track the localizer. With considerable rudder, lots of differential power, and a great deal of swearing, I managed to plant the airplane firmly on the runway.
The washing-machine sky that we had flown through for the past two-plus hours was finally above and behind us. One of my passengers drove the car home because I was simply too exhausted to do any more steering, thank you.
Another bout of approach-and-land turbulence that has earned a permanent place in my thoughts was courtesy of a Convair 580-turboprop that I was scheduled to land one late afternoon at Elmira, N.Y.
Of all the airliners I’ve flown, the Convair 580, with its big Allison engines and huge four-bladed props, was my least favorite. While it was strong on horsepower, it was noticeably weak on control harmony. Actually, it had the potential for reasonable flight control responses, as long as the cockpit crew was comprised of no less than two sumo wrestlers—the Convair 580 is the epitome of an airplane with concrete-heavy flight controls. On the turbulent day in question, neither I nor the copilot fit the sumo-wrestler bill, so we would have our athletic abilities taxed severely.
It was rainy, blustery, and just warm enough not to snow. The airport, ringed by some higher terrain, includes a few large ridges which added bountifully to the wind-induced churns and bumps down low. A healthy breeze necessitated a circling approach, which we were just beginning when the thuds of whirling atmosphere began to seriously rock the airframe every few seconds. The terrain skittered by a few hundred feet below, the airport was a mile or so to the left, and the damned Convair could hardly be coaxed in the proper direction.
I was lots younger and stronger back then, but there was no way I could take either hand off the big iron control wheel in front of me; anything less than all my efforts with both hands locked firmly to the flight controls would, as they say, be ineffectual.
“Power!” I shouted over the constant screeching of the twin turboprops.
The copilot—an experienced fellow—instantly knew exactly what I meant.
“Back …back some more…now add some…hold it… get ready…back!”
We bounced and jolted toward the runway threshold, with the necessary piloting duties being split between the two of us because it was simply too damn rough for me to take even one of my 10 fingers off the control wheel. Now, that was a bumpy day.
Yet turbulence up high has sometimes been a match for the turbulence down low. The nice part about jet transports is that you’re often above all the visible weather—but that doesn’t necessarily mean that you’re always above the turbulence. Clear air turbulence will often set your teeth ajar, and every now and then it will do more than that.
We were westbound toward Los Angeles in a Boeing 737 one late afternoon. The skies were pleasant, and I could see the Rocky Mountains clearly as we approached Alamosa, Colo.
The airplane was heavy, and our cruise altitude was Flight Level 310, which was as high as I cared to go with this much of a load in the airplane. Unlike reciprocating engine airplanes, jet transports run out of wing before they run out of engine power, so cruise altitude selection is based on providing yourself with a suitable margin between low-speed stall and high-speed Mach buffet; the margins can be uncomfortably thin if you allow them to be, and a bunch of sudden bumps in the aerial road can wipe those thin operating margins away in an instant.
The first clue that something wanton was happening was a steady and alarming increase in airspeed. The auto throttles were pulling back the power levers, but not quick enough to keep the situation in check. I disconnected and yanked the twin throttles to flight idle. Airspeed continued to increase. I disconnected the autopilot and pulled back on the hydraulic lever to fully raise the big speedbrake panels on top of the wings. Unbelievably, the airspeed continued to increase rapidly. To prevent a high-speed Mach buffet, I had to allow the Boeing to climb.
We were suddenly being pushed upward, at the maximum airspeed I could possibly let us fly, with both engines at absolute idle and full speedbrakes deployed! We had become a 60-plus-ton glider, being pushed up steadily through Flight Level 320, then 330.
The ride was perfectly smooth, but totally unacceptable because I knew that whenever the column of air that had us in its grip decided to let go, we would suddenly be at too high an altitude to prevent the wings from just giving up. Jet upset is what that situation is called.
Out of desperation I was just about to call for the landing gear to be thrown out—I needed more drag to get the jet lower—when the turbulence hit. The instrument panel became totally unreadable, and I was simply hanging on to the flight controls. But at least the unwanted climbing had stopped and I was soon able to nudge the 737 back toward our assigned altitude and down into thicker, more flyable air.
The turbulence kicked at us a few more times for good measure, then quit as quickly as it had begun. It was like waking up from a bad dream; the situation was back to normal in a blink of an eye. From beginning to end, it had been hardly more than a one-minute experience.
The worst ride I ever had occurred in an even larger airplane, and it lasted longer. We were inbound to Charlotte, N.C. in a Boeing 757, the copilot at the controls, on a nonstop flight from San Francisco that was due in shortly after dark. There was a small line of weather to the west of the airport that we had come across the tops of; radar showed it as light to a few patches of moderate rain, and the tallest clouds in the group barely touched 16,000 feet.
We steered north of the airport for traffic sequencing, then turned southbound to intercept the ILS for 18R. The weather returns were lined up on a north-south line a little to the west, and the closest batch of it to the localizer was no nearer than six or seven miles. Inside the blobs of radar green and yellow, a few little dots of heavy-rain red had begun to show. We were level at 3,000 feet, on the localizer, waiting for the glideslope indicator to begin its slide from top-of-scale.
First clue was the winds aloft. The readout from the inertial navigation display showed a sudden increase of over 100 knots, from right to left, directly across our flight path. We had hardly even digested that fact when the turbulence began: giant sickly kicks in the side of the airliner that were just about the worst sensation I had ever experienced in an airplane. It felt like an enormous foot was being put into our midsection every couple of seconds, and it didn’t take too many of those to realize that this was no longer the place to be.
“Turn, turn!” I shouted to the copilot while I pointed to the east. My feeling was that, everything else be damned, we had to get ourselves away from this broadside horizontal tornado as quickly as we could. As soon as I could get a word in, I told approach control we were making an emergency turn to the east because of severe turbulence.
The approach controller came back with an immediate clearance to do anything we wanted, then offered the news that the line of weather to the west was rapidly transforming into big areas of very heavy weather that was apparently going to pass north and west of the field. Wind at the airport had just shifted abruptly, too. Did we want to swing around for the back course ILS to Runway 23, before a second line of developing weather further west headed our way?
Suggestion accepted, and with some really quick cockpit coordination between the copilot and me, Plan B was firmly in effect a few moments later.
As we continued with the new approach, turbulence eventually transformed itself to light, the wind held steady on the nose, and the velocity readouts dropped to more customary numbers. From beginning to end, the severe turbulence had lasted no more than three to four minutes, but it was long enough to make an impression on me that I’m not apt to forget.
That episode, and the ones that came before it, have left no doubt in my mind that the absolutely best place to experience periodic encounters with heavy-to-severe turbulence is in your memory.
Editor-at-large Thomas Block has flown nearly 30,000 hours since his first hour of dual in 1959. In addition to his 36-year career as a U.S. Airways pilot, he has been an aviation magazine writer since 1969, and a best-selling novelist. Over the past 30 years he has owned more than a dozen personal airplanes of varying types. Send questions or comments to editor@www.piperflyer.com.
