An airplane in flight moves around three axes of rotation — longitudinal, lateral, and vertical. These are imaginary lines that run, perpendicular to each other, through the plane’s center of gravity. An aircraft’s rotation around the longitudinal axis, running from the nose to the tail, is called roll. Pilots control the roll via the ailerons, the movable surfaces near the trailing edges of the wings. Ailerons work together and are tied to the control wheel in the cockpit. When a pilot turns the control wheel to the left, the aileron on the left wing goes up and the one on the right wing goes down. The opposite occurs when the pilot turns the wheel to the right. This results in roll, or banking, because when an aileron is lowered, the lift on the outer portion of the wing increases, causing the wing to rise slightly. Conversely, a raised aileron decreases the lift on the wing, causing it to drop.
A plane’s rotation around the lateral axis, extending from one wingtip to the other, is called pitch, and it is controlled by the elevators on the horizontal part of the aircraft’s tail. Like the ailerons, elevators are tied to the control wheel in the cockpit. When the wheel is pulled back, the elevators move up, causing the tail of the plane to move downward and the nose to lift upward. Pushing the wheel forward causes the elevators to move downward, lifting the tail up and pushing the nose down. The elevators work like ailerons on the wings in the sense that they influence the lift generated by the plane’s tail. But unlike the ailerons, the elevators do not work in opposition to each other — they both go up or down depending on what the pilot does with the control wheel.
Finally, rotation around the plane’s vertical axis, the line running from beneath the plane to above it, is called yaw. Yaw is controlled by the rudder on the rear edge of the tail, which is connected to pedals at the pilot’s feet. By pushing the right pedal, the pilot causes the rudder to deflect to the right. The tail moves to the left, causing the nose to move to the right. Stepping on the left pedal, naturally, has the opposite effect.
The control wheel and rudder pedals in the cockpit are not linked together, but they must be used simultaneously to control the plane. The pilot guides the plane through careful, precise, and well-practiced movements, and by adjusting the airplane’s thrust, or forward force.
I realize that for some of the nonpilots out there, this might fall into the “more than I needed to know” category. But one of my goals for this column is to give our customers a glimpse into some of the interesting things happening behind the scenes — or in this case, behind the cockpit door — at our company. On behalf of our skilled aviators, and indeed the entire American Airlines and American Eagle team, I want to thank you for flying with us today. Sit back, relax, and leave the flying to us.
GERARD J. ARPEY
Chairman & CEO
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