The Basics of Flight

Safety Spotlight: Pinch Hitter

If you focus on the basics, flying an airplane is not complicated.

Airplanes are built to be stable. The next time you fly, ask your pilot to take their hands off the controls. There won’t be much, if any, change in the aircraft’s position.

The Four Forces

Four forces act on an airplane that determine how it flies.

Lift: While in flight, the airplane is supported by lift. Lift is the force acting opposite of gravity and is generated whenever air flows smoothly over a wing. As air flows over and under the wing, an area of low pressure is created above the wing, acting to pull the airplane up. When lift exceeds gravity, the aircraft will leave the ground and climb.
Weight: Weight is caused by gravity and acts to pull the airplane toward the ground.
Thrust: The airplane’s propeller acts like a wing turned on its side. In this case, the lift is known as thrust, and the low pressure in front of the propeller pulls the airplane forward, much as the engine and propeller of a ship provide thrust in the water.
Drag: Drag is the force that opposes thrust. It’s the same force you feel if you extend your arm out of the window of a fast-moving car. As you might imagine, drag increases as speed increases.

If you focus on the basics, flying an airplane is not complicated.

Extra Credit: Angle of Attack

The amount of lift a wing will generate depends on several factors. One very important factor to pilots is a concept called angle of attack.

“Angle of attack” is the angle at which the wing is slanted toward the airflow. Generally, increasing the angle of attack increases lift. That’s why the airplane’s nose is up in a climb. But, like other things in life, too much of a good thing can cause problems. If we slant the wing up too much, the formerly smooth airflow above the wing becomes turbulent. Since a smooth flow of air is required for lift, a too-high angle of attack causes the wing to lose lift. This is called the “critical angle of attack” and it is the point at which the wing stops flying. It is also referred to as an “aerodynamic stall.” This “stall” is different from what you might think of in a car. When a car stalls, we mean the engine has quit. When an airplane stalls, it means the wings have exceeded their critical angle of attack and can no longer create enough lift to support the weight of the airplane. The solution to this problem is very simple—lower the nose of the airplane (reducing the angle of attack) to smooth out the airflow and you will regain lift.

Pilot Controls

Yoke: The main control is the yoke, or stick, which is like the steering wheel in a car. It is used to pitch the airplane up and down and roll the airplane left and right. When you pull back or push forward, you move the elevator. When you roll left or right, you move the ailerons.

Pitch

Roll

Rudder: The rudder is the movable part of the airplane’s tail. The rudder is controlled by the foot pedals and is responsible for ground steering and controlling yaw. The rudder pedals also typically control the brakes.

Flaps: Extending the flaps helps the airplane fly at slower speeds—such as when landing. Not all flap controls are the same, so ask your pilot where to find the flaps the next time you fly.

Manual flap lever Electronic flap lever

Landing gear: If your airplane has retractable landing gear, it is controlled by a small wheel-shaped lever.

Aircraft Movement

“Pitching” is the nose-up or nose-down movement of the aircraft. The pilot controls aircraft pitch by moving the elevator.

“Rolling” is the left or right banking motion of an aircraft. The pilot moves the ailerons to roll the aircraft left or right for turns, just as a cyclist would lean left or right in a smooth turn.

“Yawing” refers to moving the nose of the airplane left or right. The pilot banks into a turn with the ailerons and moves the nose in the proper direction with the rudder. It is possible to turn an aircraft using rudder or aileron alone, but the turn is smoother—and what pilots call “coordinated”—if both controls are used.

Engine Control

Throttle: Technically, the throttle controls the amount of air entering the engine. Treat the throttle like a gas pedal in a car: push it in to go faster and pull it out to go slower.

Mixture: The mixture controls the fuel to air ratio mixture in the engine. Pilots “lean the mixture” to keep the engine running efficiently at high altitudes. There is no equivalent in a modern car.

In the Air

Most flying is done by looking outside and referencing the horizon.

Level flight: Level flight means flying at a constant altitude—not going up or down.

Turning: When you move the yoke/stick to the left or right, the airplane will roll in that direction.

Climbing: When you pull back on the yoke/stick, the airplane starts a climb. To help the airplane climb, push the throttle forward.

Descending: When you push forward, the airplane begins a descent. To help the airplane descend, pull the throttle out slightly.