Turbulence
For most anxious fliers, nothing is worse than turbulence. Pilots find this incomprehensible. Knowing that it is not a problem for the plane, pilots can’t understand why it is such a huge problem for so many passengers. We need to address this issue both emotionally and intellectually. First, consider the facts.
Types of Turbulence
One type of turbulence is caused when the sun heats the surface of the earth. Differences in temperature cause upward and downward movement of air. A passenger in a slow-moving hot-air balloon would experience flight through such air as a gentle ascent or descent. But due to the speed of a plane, a gentle ascent becomes an abrupt bump upward, and a gentle descent becomes an abrupt bump downward. This type of turbulence is often found in desert airports such as Phoenix and Las Vegas.
Still another type of turbulence is found in clouds. Again, differences in temperature cause upward and downward movement of air. The impression in the cabin is that the plane is in violent air. Nothing could be further from the truth. It is not the air that is violent. It is speed—the high speed of the plane—that turns gently moving air into dreaded bumps. The movements that result may seem large. Yet, in most instances of turbulence, the actual distance the plane moves up or down is only a fraction of an inch and cannot be read on the plane’s altimeter.
Another kind of turbulence is caused by strong surface winds. Hills, trees, and buildings that cause upward, downward, and sideward movement of air, as it scrubs against the surface of the earth, disturb wind. As a plane flies through such air, the path of the plane is altered only slightly. Nevertheless, an anxious passenger may imagine a dangerously large deviation and worry that a wing will touch the ground, or that the plane might be driven into the ground. This is impossible for two reasons: 1) The plane has moved such a small amount that an observer on the ground would be unable to detect any deviation from the ideal path to the runway; and 2) the various slight deviations simply average out.
Clear Air Turbulence (CAT)
Turbulence can be caused by clear air turbulence (CAT) as faster moving air scrubs against slower moving air. During CAT, autopilots on large airplanes use a “turb” mode. What do you think the autopilot does when in “turb” mode? Do you think it’s more aggressive, or less aggressive? It’s less aggressive. In fact, it’s downright sluggish. There is no reason to have the autopilot correct for every bump because bumps tend to cancel each other out.
What causes CAT? As the earth spins, it produces centrifugal force that slings air away from the earth, outward toward space. This effect is greatest at the equator. Since the earth is about 25,000 miles in circumference at the equator and makes one rotation every 24 hours, the surface of the earth at the equator is moving eastward a bit faster than 1,000 mph. Even as centrifugal force spins air away from the earth, gravity seeks to pull it back. But, because air is constantly flowing up, the air has no place to go other than north or south, away from the equator.
Now, imagine you can see that air slung off from the equator again, after it has had time to migrate north or south. Because the circumference of the earth is less at any point north or south of the equator, the surface moves at a slower speed than at the equator. The equator-speed air—called the jet stream—is moving faster than the earth below. Flying from San Francisco to New York, the eastward-moving jet stream helps you get to New York faster. But when going from New York to San Francisco, you have to go against the jet stream. Staying in or out of the jet stream is easier said than done because the position of the jet stream is constantly in flux.
The Jet Stream
The jet stream is like a train that zips around the earth at the altitudes jet airliners use. Regardless of the speed of a train, the air inside is not turbulent. But just outside the train, the speed of its passage causes turbulence. At a train station, a person standing on the boarding platform has trouble reading their newspaper when a train passes by. That’s how it is with the jet stream. Inside the jet stream where all the air is moving at the same speed, the air is smooth. But where the fast-moving air meets air that is moving slower, there is turbulence.
To understand how simple and mechanical jet stream turbulence is, place a pencil on a table. Put your palm on top of the pencil. Now, push your hand forward. This causes the pencil to roll. Your hand represents the jet stream moving forward. The table represents air that is standing still. The pencil represents air that, because it is rolling as it moves forward, is turbulent. Because it is fluid, air is free to shape itself, and it shapes itself into roller bearings that allow the faster moving jet stream air higher up (represented by the hand) to ride on roller bearings of air.
Now, pick up the pencil. Using both hands, hold one tip of the pencil with the fingers of your left hand and the other with the fingers of your right hand. Hold the pencil horizontal at eye level, and rotate it with your fingertips so the side nearest you is rotating upward. That means the other side of the pencil, though you can’t see it, is rotating downward. Think of the pencil as a roller bearing that is rotating due to being sandwiched between the fast-moving jet stream air on top and the slower air underneath. When a plane enters the front edge of the rotating air, it bumps up. The distance from the front side of the roller to the back might be the size of a football field, so in half a second, as the plane reaches the back edge (that is rotating down), it bumps down as it exits. Then the plane flies right into the next roller; it again bumps up and down, and goes into the next roller, and so on. Since the plane spends only a fraction of a second bumping up or down, the distance the plane ascends or descends is no more than a fraction of an inch.
By monitoring the radio, pilots usually know if there is CAT ahead on the route. Still, CAT can be encountered unexpectedly. An area on your route that had been smooth for hours can become rough just as your plane reaches it. Areas of turbulence are usually too wide to try flying around. But since turbulence is limited vertically, climbing or descending can often eliminate it. Your captain will ask the Air Traffic Control if there are any altitudes that are reportedly smoother. If a smooth altitude is both practical and available—not in use by other planes—the captain will climb or descend to it. Keep in mind that there are limits to how high a plane can fly. The higher you go, the thinner the air, and the less power the engines produce. If a descent below the turbulence means cruising several thousand feet lower, it may be impractical due to greater fuel consumption resulting from the thicker air.
Other Turbulence at Cruising Altitude
Planes can navigate around scattered thunderstorms that extend to cruise altitude. Though the plane can fly through thunderstorms, they are avoided, both for passenger comfort and because they may contain hailstones. Running into hailstones at five hundred mph pockmarks the leading edge of the wing. These pockmarks are expensive to repair, and, if not repaired, slightly increase fuel consumption. When thunderstorms form a line, pilots use radar to find the least turbulent area.
Turbulence and Wind Shear
Wind shear is an abrupt change in the velocity of wind horizontally. Since turbulence is caused by changes vertically, turbulence does not necessarily mean wind shear. Wind shear with a velocity change great enough to pose a problem is rare, so rare that for many years the presence of wind shear during takeoff or landing was addressed by a slight speed increase. After it became known that wind shear could pose a risk in exceptional situations, pilots were trained to recognize and avoid those situations. Then, Doppler radar was developed to detect it. If Doppler radar shows wind shear approaching the cautionary range, the entire airport is shut down until the velocity of the wind shear returns to a normal range.
Turbulence during Descent and Landing
Routes increasingly narrow as traffic funnels toward the airport. To obtain the best inbound routing, pilots rely on cockpit radar, reports from pilots ahead, and Air Traffic Control. If a severe storm moves directly over the runway, landing is halted due to the possibility of wind shear. Depending on fuel remaining, planes hold until the storm moves away from the airport or divert to an alternate airport where weather is not a factor.
The Seat Belt Sign Does Not Mean Danger
First, turbulence is not a danger for the plane. Second, passengers wearing a seat belt never get hurt due to turbulence. Third, in some cases the seat belt sign is turned on at the request of the flight attendants if passengers in the aisles are making drink and food service difficult. The seat belt sign is often put on early to aid the flight attendants as they secure the galley before it gets rough. Even when it is safe to walk around, a flight attendant can get hurt wrestling a heavy serving cart back into its narrow stowage slot in the aft galley, the part of the plane that moves around most in turbulence.
As to what is happening in the cockpit, that Hollywood movie stuff of pilots holding onto the controls for dear life is just Hollywood hooey. What do pilots really do during turbulence? They let the autopilot fly the plane as they sip their coffee or eat a snack. From a pilot’s point of view, the greatest risk during turbulence is getting coffee stains on a shirt.
Pilots Using the Lavatory
When the door of the lavatory is locked, a light illuminates in the cabin to inform passengers the lavatory is occupied. There is also a light in the cockpit so the pilots will know when it is unavailable. If a pilot needs to use the lavatory, it means waiting until the light goes out, then unhooking the headset, sliding the seat back, unbuckling the seat belt and shoulder harness, getting up to go back to the cockpit door, opening it, and stepping out of the cockpit. More often than not, by the time a pilot can get unhooked and ready to use the lavatory, the light is on again, signaling that a passenger beat the pilot to the lavatory.
I received an e-mail from a client who wrote, “When there was turbulence the pilots happened to take a trip to the lavatory. I was nervous of course, but then they waved at me while they were shifting from the cockpit to the lavatory. I was put so much at ease. I thought, ‘If they can go to the bathroom while we’re shaking, then it must be okay.’ On my return trip the same thing happened. The turbulence was very heavy around the Midwest and I was nervous, but again the pilots came out to go the restroom.” I replied to her that use of the toilet during turbulence is standard procedure for pilots.
When the seat belt sign is on because of turbulence, passengers are supposed to remain seated. That means the lavatory is free. Typically, pilots use this time to visit the lavatory, even if the trip isn’t urgent. In all the years using this strategy, I never had the least trouble using the lavatory during turbulence. Just in case we hit a bump, I held a hand on the ceiling to brace myself. But in all my trips to the lavatory during turbulence, I never needed to use any effort to avoid the ceiling—or any other part of the lav, for that matter.
So though you might think turbulence is in some way a danger, pilots don’t feel that way at all—for them it’s an opportunity to use the lav. Remember, of course, this is the lavatory in the front of the plane. In turbulence, the back of the plane moves around more than the front. Though I had no trouble using the front lavatory, I wouldn’t have tried to use the rear lavatory during turbulence—no one should.
Knowing Turbulence Is Safe Is Not Enough
When I was a 747 copilot, I flew many trips between New York and Tokyo. On a fourteen-hour flight, there is plenty of time to talk, and on one flight, a captain who knew I was working with fearful fliers asked me, “Well, what are people afraid of anyway?” His use of the word “anyway” shows, I think, how puzzled pilots are that anyone would think flying is something to be feared. So when I told him “turbulence,” he was dumbfounded. He said, “What! Why?” I tried to explain, but nothing I said made any sense to him. Exasperated, he said, “Well, I can fix that.”
He went on to tell me that when he came to work at the airline, being at the very bottom of the copilot seniority list, he was assigned the flying that was left over after everyone else had had their pick. That meant he was stuck with flying cargo through Central America in the middle of the night on piston-powered propeller-driven Douglas DC-6s. Since there were no passengers on the flight, the airline saw no reason to equip the planes with radar. So the pilots had no way to know where the thunderstorms were, and Central America has some of the worst thunderstorms in the world. In light of that, the captain said, they just wore their seat belts and their shoulder harnesses and put the plane on autopilot and drove straight ahead. If they missed the storms, fine, but if they hit one, the plane would “buck and snort and moan and groan,” as he put it.
On his first few flights he wasn’t sure that the plane would stay together. But taking a cue from the seasoned pilots he was flying with, who seemed completely bored when charging through the storms, he decided not to exhibit any concern. He told me, “I never got to the point that I liked it, but I did get to the point that I realized the plane could handle anything! Tell people that,” he said, “and that will cure them.”
Though I’ve told many people that story, and though they may have finally been convinced the plane can handle anything, there is another issue when it comes to turbulence. It’s not just a question of whether the plane can handle it physically. It’s a question of whether an anxious passenger can handle it psychologically.
Even after a person understands that turbulence is safe, it continues to be identified—misidentified, that is—as a thing to be feared. It would be more accurate to say that turbulence defeats a common strategy for keeping fear at bay. For many people, emotional safety depends upon control. Without control, escape is required. Since flying offers neither physical control nor physical escape, emotion can be controlled only by psychological escape. Keeping the mind off the flight may work if the flight is smooth. But when turbulence intrudes, psychological escape is impossible. The person’s only remaining strategy is defeated. Turbulence is feared because it renders them powerless to control emotion.
What can be done? In addition to the Strengthening Exercise, which works automatically, Chapters 9 and 22 offer several techniques you can employ consciously to deal with turbulence.