Quiz on Forces Acting on an Airplane

The four forces acting on an airplane in flight are

• lift, weight, gravity, and thrust.

• lift, gravity, power, and friction.

• lift, weight, thrust, and drag.

What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight?

• Lift equals weight and thrust equals drag.

• Lift, drag, and weight equal thrust.

• Lift and weight equal thrust and drag.

Which statement relates to Bernoulli’s principle?

• For every action, there is an equal and opposite reaction.

• An additional upward force is generated as the lower surface of the airfoil deflects air downward.

• Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface.

When are the four forces that act on an airplane in equilibrium?

• When the aircraft is at rest on the ground.

• During unaccelerated level flight.

• When the aircraft is accelerating.

Which statement is true concerning primary flight controls?

• Primary flight controls include ailerons, rudder, elevator, and trim systems.

• The effectiveness of each control surface increases with speed because there is more airflow over them.

• Only when all three primary flight controls move in sequence do the airflow and pressure distribution change over and around the airfoil.

Trim systems are designed to do what?

• They relieve the pilot of the need to maintain constant pressure on the flight controls.

• They move in the opposite direction from one another to control roll.

The elevator controls movement around which axis?

• Lateral.

• Vertical.

• Longitudinal.

Which is not a primary flight control surface?

• Ailerons.

• Stabilator.

• Flaps.

One of the main functions of flaps during approach and landing is to

• decrease the angle of descent without increasing the airspeed.

• permit a touchdown at a higher indicated airspeed.

• increase the angle of descent without increasing the airspeed.

Which device is a secondary flight control?

• Ailerons.

• Spoilers.

• Stabilators.