Definition
Flight controls that supplement the primary flight controls (ailerons, elevator, and rudder) to improve aircraft performance, reduce pilot workload, or modify the wing's lift and drag characteristics. Common secondary flight controls include flaps, slats, spoilers, leading edge devices, and trim systems.
Plain English
These are the extra controls on an aircraft that help the pilot fly more efficiently. They don't steer the airplane like the main controls do — instead, they fine-tune how the wings produce lift, slow the airplane down, or relieve the pilot from holding pressure on the main controls.
Context Anchor
Seen in aircraft control-system discussions, especially when learning how high-speed aircraft use added surfaces and systems to manage speed, handling, and landing performance.
Derivation
‘Secondary’ comes from the Latin secundarius, meaning ‘of the second rank’ or ‘following the first.’ These controls are called secondary not because they are less important, but because they support and supplement the primary controls that actually steer the aircraft.
Why Pilots Care
They enable precise speed and configuration management critical for safe takeoff, approach, and descent at both low and high speeds.
Intuition Check
Secondary does not mean “backup” here. It means these controls are additional controls that assist the main flight controls.
Example Sentence 1
Before landing, the pilot extended the flaps, a secondary flight control, to allow a slower approach speed.
Example Sentence 2
Spoilers, one type of secondary flight control, were used to reduce lift and increase descent rate without raising airspeed.