Question

What causes an airplane (except T-tail) to pitch nose down when power is reduced and controls are not adjusted?

1) Decreased lift on the horizontal tail surfaces
2) Increased lift on the horizontal tail surfaces
3) Decreased drag on the horizontal tail surfaces
4) Increased drag on the horizontal tail surfaces

Answer 1

The correct answer is option 1) Decreased lift on the horizontal tail surfaces.When power is cut back on an airplane, decreased lift on the tail surfaces causes the nose to pitch down due to the imbalance between the lift on the wings and tail.

Step-by-step explanation:

When power is reduced on an airplane, the thrust provided by the engines is also reduced. As thrust decreases, there is less air flowing over the wings and the tail, which means the lift generated by these surfaces also decreases. The tail of the aircraft typically produces a downward force to balance the aircraft; when the lift on the tail decreases more than the decrease of lift on the wings due to power reduction, the balance is disrupted, resulting in the nose of the aircraft pitching down. This behavior is rooted in the design of the aircraft to promote stability and increase safety during flight operations.

The horizontal tail surfaces, including the elevator, play a crucial role in balancing the aircraft and controlling its pitch. When the power is reduced, the downward force applied by the blades decreases, causing a decrease in lift on the tail surfaces and resulting in a nose-down pitching motion.