Definition
Spoilers that deploy symmetrically on both wings at the same time, used to reduce lift and increase drag without producing a roll. They function as speed brakes or lift dumpers rather than as roll control devices.
Plain English
Panels on top of both wings that pop up together, evenly, to slow the airplane down or help it stop flying so it settles onto the runway. Because they come up the same amount on each side, they don't make the airplane roll.
Context Anchor
Seen in high-speed aircraft flight control discussions, especially when comparing spoilers used for slowing or descending with spoilers used for roll control.
Derivation
Non-differential' means 'not different between sides.' 'Spoiler' comes from the idea of spoiling, or disrupting, the smooth airflow over the wing. Put together: panels that disrupt lift equally on both wings.
Why Pilots Care
Provides a direct way to manage airspeed and descent angle in high-speed flight without pitching the nose down or rolling the wings.
Grounding Statement
Picture both wing panels rising together: the airplane keeps its wings level, but the wings make less lift and more drag.
Intuition Check
“Non-differential” does not mean the spoilers are unimportant or inactive. It means the spoilers do not move differently from one wing to the other.
Example Sentence 1
After touchdown, the non-differential spoilers deployed automatically, dumping lift and putting the aircraft's weight firmly on the wheels for braking.
Example Sentence 2
In high-speed cruise, non-differential spoilers allowed a controlled reduction in altitude without changing pitch attitude.