How Flying Works
To feel emotionally safe, you need to feel physically safe. Though flying is one of the safest things you can do, statistics are not enough. You need to become a mini-expert. You need to know, for example, that the wings are far too strong to break. You need to know that things that could break are backed up. You need to know what the backups are, and what pilots do to take care of problems.
Stability
What keeps the plane from flipping over?
Some of the things anxious fliers worry about simply can’t happen. As you become a mini-expert, you will be able to rule out some of these fears. One concern is that the plane will flip over. Perhaps it’s from Hollywood movies. Perhaps it’s from media hype. Perhaps it’s from your own imagination. But the plane is not on the verge of going out of control at every moment. An airliner, like any vehicle, has built-in dynamic stability. Dynamic stability is the tendency of a vehicle to move straight ahead unless it is forced to do otherwise.
You can try out dynamic stability by taking your car to an empty parking lot. Turn the steering wheel to start making a circle. It takes effort. You have to hold some pressure on the wheel. If it were not for the power steering on your car, it might take a lot of effort. If you let go of the pressure, the steering wheel centers itself and the car travels straight ahead. The same dynamic stability is build into an airliner. If the pilot turns the wheel to start making a circle, it takes effort. The pilot has to hold pressure on the wheel. If the pilot lets go of the pressure, the wheel centers itself and the plane glides straight ahead.
This tendency to move straight ahead is caused in a car by the way the front wheels are attached, and in a plane by the way the wings are attached. Did you make paper airplanes when you were a kid? To make it fly straight, you bent the wings upward into a V shape. This upward angle of the wings is called dihedral. You didn’t have to be an aeronautical engineer to use dihedral to give your paper airplane stability. You found out by trial and error, or an older kid showed you.
Next time you look at an airliner, notice that, as you look from the fuselage outward toward the tip of the wing, the wing rises slightly. That’s dihedral. (In case you didn’t know it, the fuselage is the central body of the plane to which the wings and tail assembly are attached.)
How a Plane Changes Direction
It’s scary when a plane dips and turns. What’s happening?
When a bicycle or motorcycle turns, it leans into the turn. So do speedboats and planes. Pilots call it banking. When a plane starts to bank, it’s tempting to think the angle might increase enough to turn the plane upside down. That’s because, as a passenger, you’re not aware of the effort required to make banking happen. For a car to turn, pressure must be applied to the steering wheel. Similarly, for a plane to bank, pressure must be applied to the control wheel. It takes some pressure to bank the plane a little. It takes more pressure to bank more. The plane never banks more than the pilot causes it to because dihedral is always trying to return the wings to level.
Like an arrow, the plane goes where it’s pointed unless caused to do otherwise by the pilot. To point the plane in a different direction, the pilot has to turn the plane by banking it. For example, to turn left, the plane needs to bank to the left, tilting the left wing down and the right wing up. To do that, the pilot applies pressure on the control wheel to move it to the left (counter-clockwise) and hold it there. The control wheel is attached to ailerons, horizontal panels on the rear of each wing. Normally, the ailerons are in a neutral position and have no effect on the wing. But to turn left, the ailerons on the left wing are moved up against the airflow, to tilt the left wing down, while the ailerons on the right wing are moved down against the airflow, to tilt the right wing up.
By maintaining pressure on the control wheel, the pilot keeps the ailerons deflected against the airflow until the plane has turned to point in the desired direction. Once this has been achieved, the pilot relaxes the pressure. The ailerons return to their neutral positions. The wings return to level. The plane stops turning and again flies straight ahead.
Unlike Hollywood movies in which pilots hold onto the controls for dear life, pilots do not need to touch the controls unless they want to point the plane in a different direction or to climb or descend. Airliners plummet—or plunge, or dive—only in Hollywood movies, or in “movies” you create in your own imagination. If you see an airliner plummet in a movie, know it is fantasy. Planes do not uncontrollably plummet or plunge. In a steep descent, as the plane’s speed increases, the wings produce more lift. The increased lift stops the plane from going down so rapidly. When a plane is at cruise altitude, if there is a problem with the pressurization system that cannot be corrected, the pilots do an “emergency descent.” In an emergency descent, the throttles are brought back to idle, the speed brakes are extended, and the landing gear is extended. This keeps the plane from picking up excessive speed when the nose is lowered. And if you “see” an airliner plummet in your own mind, know that it, too, is fantasy.
Climbing and Descending
When I feel the plane go down, I’m afraid it’s falling.
Though a pilot could begin a climb or descent so smoothly you wouldn’t even notice it, there are reasons why it isn’t done. First, most pilots don’t know that even routine movements of the plane can make a passenger feel anxious. Second, pilots like to feel the plane respond when they move the controls. Third, Air Traffic Control expects altitude changes to be made more quickly than a gentle climb or descent would allow.
Your amygdalae may tend to react to these changes, but by using the Strengthening Exercise, you can train them not to.
A plane can be made to climb in two ways. One way is simply to increase the power. As the speed starts to increase, the nose gently rises to maintain the same speed. Likewise, to descend, simply decreasing the power will cause the nose to gently lower to maintain the same speed. The other way to climb is to point the nose higher by pulling back on the control wheel. This causes the elevator—a panel on the rear of the horizontal tail surface—to deflect upward against the air stream, which causes the rear of the plane to lower and the nose to rise. Power must be increased if speed is to be maintained. To descend, pushing forward on the control wheel causes the elevator to deflect downward against the air stream, which causes the rear of the plane to rise and the nose to lower. Power must be reduced if speed is to be maintained.
Rudder
How do you keep the plane going straight in strong winds?
It’s no more difficult than what you do in your car when you’re driving in a crosswind. During takeoff, we steer the plane down the middle of the runway with the rudder. We use a little pressure on the rudder to compensate for the crosswind.
We also can compensate for the crosswind by slightly turning the nose wheel (that’s the front wheel, beneath the pilot’s cabin). Generally, we steer with the nose wheel during taxi and on takeoff until the air is moving fast enough past the rudder for it to be effective.
The rudder is also needed for a crosswind landing when the wind—instead of being lined up with the runway—is blowing across the runway.
Airliners have two or more engines. As you may know, an airliner can fly on just one. But if the engine on the left wing is working and the one on the right wing is not working, doesn’t it push the airplane sideways? Yes, it does. That’s why planes have a rudder. If there is more thrust on one side than the other, the rudder can compensate. It isn’t difficult. On a car, if a tire goes flat, the car pulls to the side. The driver uses the wheel to compensate. With the airplane, if one engine is pushing more than the other, pilots use the rudder to compensate.
Engines
I’m afraid that if the engines quit, the plane is just going to fall.
Many believe the airplane is held in the air by the engines, and that if the engines quit, the plane will fall like a rock. Not so. The plane is basically a glider. Though power from the engines is needed to push the plane forward through the air when climbing and when cruising, going downhill is effortless. No power is needed at all. The plane just glides down. Even though it’s heavy, the plane is so perfectly shaped that, for well more than a hundred miles, it glides down from cruise altitude with no need for engines at all before leveling off in the airport’s traffic pattern to get into position for landing.
Adventurous people leap off cliffs and glide down on hang gliders. Even though a jetliner is heavy, its aerodynamic shape is so well designed that its glide performance is twice that of a hang glider! Consider another glider: the space shuttle. It’s blasted into space by a rocket. The rocket falls away. Momentum carries the shuttle into orbit. When it comes back to land, it just glides down. Every landing is done completely without engine power. Your airliner has much bigger wings than the space shuttle; it glides far better than the space shuttle does. So next time the thought of “what happens if the engines quit?” hits you, remember the many times you have seen the space shuttle descend without any engines and touch down perfectly on the runway.
People who believe the engines hold up the plane sit on pins and needles, expecting the plane to fall at any moment. If the initiation of a normal descent doesn’t cause you terror, there’s no reason to expect terror if engines were to fail. Why? Because the glide with engines inoperative is indistinguishable from the glide of a normal descent. In either case, the nose needs to be lowered only two to three degrees below the horizon for gravity to maintain the speed necessary for flight. From cruise altitude the plane can glide for twenty to thirty minutes, plenty of time for the pilots to correct any problem with an engine or, like the space shuttle, to glide down to a runway and land.
Nonetheless, to ensure reliability, jet engines are constantly monitored. Sensors transmit data to a computer that tracks engine performance. Any abnormality in operation is detected long before it becomes a problem. In addition, a periscopelike device regularly inspects the interior of the engine. If it is not operating properly, the captain may elect to shut down the engine. A three- or four-engine plane may continue the flight, but regulations require that a two-engine plane land as soon as practical. To understand how rare engine problems are, consider that initial certification of the twin-engine 767 for trans-Atlantic flight required two million hours of domestic flying without any engine problem. Two million hours! In spite of that figure, it’s easy for an anxious flier to think, “What if they both quit?” Have you ever seen two lightbulbs in your house burn out at the same time? Incandescent bulbs last from 800 to 1500 hours. Fluorescent bulbs last about 10,000, one two-hundredth as long as the engines showed they could go without failure. I’ve never seen two bulbs burn out at the same time. I doubt that anyone has. From that point of view, the idea of jet engines burning out at the same time becomes almost unthinkable.
In spite of how rare engine failures are, every takeoff is planned so that an engine failure can occur without creating an unsafe condition. When planning the takeoff, the pilots calculate three speeds: V-1, V-R, and V-2 (V stands for “velocity”). Each V-speed is a checkpoint during takeoff. Before reaching V-1, the takeoff will be aborted if an engine fails. If an engine fails after reaching V-1, the takeoff will be continued. Since the plane can fly on one engine, it is safer to continue the takeoff—and then to land using the full length of the runway to stop—than to stop with limited runway remaining. V-R is the speed at which the nose is lifted off the runway. V-2 is the speed at which the plane initially climbs following an engine failure. A slightly higher initial climb speed is used with all engines operating.
Though rare, planes do sometimes collide with birds. In my thirty-eight years of flying, I collided with a bird only once. There was no damage whatsoever to the plane. But if the bird happens to be in just the wrong spot, it can be ingested into the engine. Engines are built to be able to ingest birds and still run. But a large bird may bend fan blades enough to cause vibration inside the engine. Since jet engines came into use in the 1950s, only one airliner has been forced to land due to bird ingestion. In that instance, a flock of birds caused both engines to lose power. The plane did not fall out of the sky: It glided down for a landing in the Hudson River where, due to buoyancy of the fuel tanks, it floated.
Primary, Secondary, Backup, and Emergency Systems
In my car, if something goes wrong, I can pull over to the side of the road. But if something happens to a plane, I’m dead.
A person unfamiliar with aeronautical engineering might think that if anything goes wrong, the flight is doomed. It just isn’t that way. Imagine your car had two engines. If one quit, you could keep going with power provided by the other engine. Same thing with powerboats; a lot of them have two engines. With an airliner, safety requires redundancy. We have two, three, even four of everything needed for normal operation.
Each system is tested before flight and is monitored during flight. The primary systems are used when flight begins. As the flight progresses, if any primary system begins to operate outside of normal parameters, the plane automatically switches to an identical secondary system. If the secondary system restores normal operation, the pilots are not even informed until the plane is parked, so that the primary system problem will be reported to maintenance.
If the secondary system doesn’t restore normal operation, the instrument panel displays a message informing the pilots. Using prescribed steps on a checklist, the pilots switch to a backup system. Backup systems are less complex. By removing some of the sophistication built into the primary and secondary systems, the backup system is usually able to restore normal operation. If the backup system doesn’t restore normal operation, the pilots—using the checklist—switch to the even more basic emergency system.
As an example, consider the braking system. To allow heavy braking without damage to the tires, airliners have sophisticated anti-skid systems. In a typical design, if a fault develops in the primary braking system, the system automatically switches to a secondary system. If the secondary system does not isolate the fault and restore proper braking, a light comes on, and the captain switches to a third system. Should the third system not work perfectly, it automatically switches to a fourth system. And if the fourth system does not perform properly, a light comes on telling the captain to manually switch to the emergency system. The emergency system bypasses the anti-skid system and sends hydraulic pressure to the wheel brakes according to the amount of force the pilot applies to the brake pedals. With the anti-skid system bypassed, the pilots need to brake judiciously to avoid damaging the tires, just as you would if driving an automobile not equipped with anti-skid brakes.
Even though there are redundant systems, each system is designed for a high degree of reliability. In years of flying airliners with the braking systems described above, not once did I have to use even the secondary braking system!
Traffic Collision Avoidance System (TCAS)
What if another plane gets in your way? What keeps you from hitting other planes?
It may be helpful to understand that pilots can be as obsessed with control as an anxious passenger might be. Pilots are comfortable only when they know they have everything under control and can keep it that way. Obsession with control led to the development of TCAS, the Traffic Collision Avoidance System. Pilots knew they could depend on Air Traffic Control (ATC) to maintain separation between them and other planes at 18,000 feet and above. But below 18,000 feet, small planes are sometimes not controlled by ATC. Small planes are hard to spot when flying toward the sun, or in hazy conditions. Feeling vulnerable, pilots wanted better control.
Research to develop a collision avoidance system pilots could use in the cockpit began all the way back in the 1950s. When the Airline Pilots Association began lobbying Congress to have TCAS installed, airline management and air traffic controllers opposed the device. Some argued that the money spent developing and deploying such a system would be better spent elsewhere. Wanting more control of collision risk, pilots continued their efforts. As a result, it finally became law that every U.S. Airliner had to have TCAS installed by December 1991. Other countries soon followed.
In the cockpit, the TCAS displays other aircraft at or near the same altitude. A computer determines whether any of them could pose a collision threat. If the computer finds any possibility of a threat, it alerts the pilots. If the threat shifts from possible to actual, the computer directs the pilots to climb or descend. Pilots follow instructions from the TCAS and immediately advise Air Traffic Control of the change in altitude.
Ground Proximity Warning System (GPWS)
Most accidents are caused by pilot error. I’m worried that the pilot may make a mistake.
Airline flying is remarkably safe for numerous reasons. One of the many is that, following any accident, investigators make recommendations to prevent that type of accident from happening again. As a result, airliners are now equipped with devices that prevent pilot error. An example is GPWS, the Ground Proximity Warning System. For years, one type of accident, tabbed Controlled Flight Into Terrain (CFIT), had continued to occur in spite of changes in cockpit procedure intended to prevent such accidents. Controlled Flight Into Terrain means a perfectly functioning plane was flown unknowingly into the ground.
In 1969, Don Bateman, the Chief Avionics Engineer for Honeywell, began developing a system to prevent CFIT. Bateman’s system used a radar signal from the plane to determine the distance between the plane and the ground. If the system saw the plane closing in on the ground, it automatically checked the position of the landing gear and flaps. If they were not in the proper position for landing, the system assumed the pilot was heading toward the ground—not intentionally for landing but unintentionally and unknowingly. This triggered flashing lights and a voice command—“Pull Up, Pull Up”—that continued until the pilot regained a safe altitude.
Ralph Waldo Emerson said, “Build a better mousetrap and the world will beat a path to your door.” Maybe that applies to a ninety-nine-cent item, but Bateman’s device was expensive. Though this device was the solution to the CFIT problem, the airlines did not beat a path to his door. Nor did the FAA, the Federal Aviation Administration, in its wisdom, see fit to require airlines to purchase it. But something changed all that.
Normally, when Air Traffic Control issues a descent clearance, the altitude specified is higher than any obstruction on the ground. But on December 1, 1974, a Trans World Airlines 727 heading into Washington’s Dulles Airport was given a descent clearance with rarely used phraseology that did not ensure terrain clearance. The pilots, believing ATC was still responsible for terrain clearance, descended into hills twenty-five miles northwest of the airport. This CFIT accident at an airport used by members of Congress resulted in legislation that required every U.S. airliner be equipped with a Ground Proximity Warning System (GPWS). The FAA inaugurated it two weeks later—December 18!
Bateman’s GPWS device put an end to accidents in which planes unknowingly flew into the ground, at least in the United States. Foreign airlines were slow to adopt GPWS technology but did so after an Avianca 747 was unintentionally flown into the ground as it approached the Madrid airport in darkness on November 27, 1983.
Since its invention, GPWS has been improved through Global Positioning System (GPS) technology. Instead of relying only on a radar signal bounced off the ground, the Enhanced Ground Proximity Warning System (EGPWS) employs GPS terrain-height information.
Can the plane land itself?
Crashes due to pilot error in bad weather have largely been ruled out by advanced autopilot systems that lock onto signals from the runway and land the plane automatically. The most advanced systems offer such precision that landing is possible when visibility and ceiling are near zero. Special equipment is required both at the runway and on the airplane as well as simulator training for pilots certified to conduct these landings.
What Can Cause an Accident?
With all these safety systems, how can a crash happen?
When you consider all the redundancy built into the plane, all the safety systems, all the simulator training of the pilots, the flight planning and flight following by the dispatchers, the checks and balances in maintenance and inspection, the constant monitoring of engines, the navigation systems that allow automatic landing, it’s hard to imagine how an accident is possible at all.
Accidents and terrorism are, as most anxious fliers look at it, different things. Most say terrorism can happen anywhere. But those who still worry about terrorists can gain some help by knowing that before 9/11, domestic security was a farce. It was put into place because of an epidemic in the 1960s of “Take me to Cuba” hijackings. Screeners were paid minimum wage and training was minimal. Though those of us in the industry knew weapons could easily get through this screening, it discouraged most would-be hijackers. After a few years of no hijackings, Senator Teddy Kennedy proposed screening be discontinued as an unneeded nuisance.
At the same time, terrorist activity was on the increase in the UK, Europe, and the Middle East. Well thought out measures were put into place. Security was still not taken seriously. Though there was no increased security on a domestic flight, inspection on flights leaving the United States for Europe matched the security in place in Europe.
That all changed after 9/11. In the United States, public interest in terrorism went from nil to obsessive. Measures that should have been in place all along were suddenly implemented. Inspection on domestic flights was dramatically improved. For years airline pilots had been asking the FAA to require secure cockpit doors. The FAA’s response was that we really didn’t want such doors because if we crashed, they might jam and trap us in the cockpit. But 9/11 changed all that. In a few weeks, the secure doors we should have had all along were authorized. Had we had such doors earlier, the terrorist operation that took place on 9/11 could not have been carried out.
Some say, “Well, if flying is so safe, why are there still accidents?” The question seems to imply that safety should be absolute. Or, that when we point out how safe flying is, we are either engaged in deception, or not looking at the problem as realistically as they are. I think some self-examination is called for. Why does air safety need to be absolute while road safety can be—literally—“hit or miss?” Why the double standard? The double standard is due to psychology. When driving, a person can control their emotions; they can’t when flying. And, rather than recognize where the problem lies, it is less damaging to the ego to assign the problem elsewhere.
Whether by land, sea, or air, as long as transportation takes place, there will sometimes be mishaps. As my Air Force squadron commander once said, “The only way to make planes completely safe is to park them in freshly poured concrete.”
Levity aside, safety is taken seriously in aviation. It is considered a near miss if planes pass each other with three hundred or four hundred feet of separation. On a two-lane highway, we think nothing of zipping past oncoming traffic with a separation of only three or four feet. Though Air Traffic Control tracks air traffic on radar—and every airliner has TCAS in the cockpit as a backup—an anxious passenger obsesses about the possibility of a midair collision in spite of all the measures taken and systems in place that make such an incident a remote possibility.
Ask an airline pilot whether he or she feels safer in the cockpit of an airliner or behind the wheel of their car. You will always be told the cockpit. Why? Because the pilot has far more control and many more backups in the air than he does on the ground. Also, the pilot feels safer in the air where only professionals are encountered and the space in which these professionals operate is vast, not to mention carefully monitored by ATC.
Flying, though not absolutely safe, is remarkably safe. There is good reason to be intellectually in a state of peace about security when in the air. But there is an equally good reason to be emotionally unsettled. The reason lies simply in how we are mentally wired. When the amygdalae release stress hormones, our inner CEO needs to do its ABCs. At the moment of commitment, the CEO’s office, the orbitofrontal cortex, resets the amygdalae. It is far easier for the CEO to do its ABCs when behind the wheel of a car than when seated in the passenger cabin. It is not always easy to assess the significance of a noise or a motion the plane makes. Without an assessment, one cannot build a plan of action. With no plan of action, there can be no commitment. With no commitment, the amygdalae continue producing stress hormones.
Since your inner CEO finds it easier to do its ABCs in a car than in a plane, the car feels safer in spite of incontrovertible evidence that the plane is far safer. But since your inner CEO can recognize flying is safer, it can wisely choose to train the amygdalae not to react to the noises and motions when flying.
We’ve been flying planes for more than a hundred years. When there has been an accident, the cause has been determined and a fix put into the system to keep that from happening again. This means, for an accident to happen today, in most cases it is something that has never happened before—something that has not happened even once in the previous hundred years.