Definition
A mechanical spring installed in the flight control system that applies a constant nose-down force to the elevator. It supplements the natural pitch stability of the airplane, helping the elevator return to a trimmed position and providing the pilot with consistent control feel in pitch.
Plain English
A spring inside the control system that gently pulls the elevator down, helping the airplane behave predictably in pitch and giving the controls a steady feel.
Context Anchor
Seen in discussions of T-tail airplane handling and pitch-control design.
Derivation
Elevator comes from Latin meaning “to raise.” In an airplane, the elevator is named because it helps raise or lower the nose. “Down spring” describes a spring force that biases the elevator toward the down, nose-lowering direction.
Why Pilots Care
Prevents reduced elevator effectiveness and pitch instability that can occur in T-tail designs during slow flight or high angles of attack.
Grounding Statement
If the pilot eases off back pressure, the spring tends to help the controls move in the nose-down direction.
Intuition Check
Do not read “elevator” as a lift inside a building, and do not read “down spring” as a device that makes the airplane descend. Here, it means a spring that biases the airplane's pitch control toward lowering the nose.
Example Sentence 1
The elevator down spring keeps a steady nose-down bias on the controls, so the pilot feels consistent back-pressure during climbs.
Example Sentence 2
During preflight, the pilot checks that the elevator down spring is correctly tensioned to ensure proper pitch stability.