Definition
Hinged surfaces that extend from the wings or fuselage of an aircraft to increase drag during a dive, limiting the airspeed the aircraft can build up and helping the pilot maintain control.
Plain English
Panels that pop out to slow the aircraft down during a steep descent, so it doesn't go too fast.
Context Anchor
You may see this term in aircraft systems descriptions, older military aircraft manuals, or performance discussions about steep descents and dive recovery.
Derivation
Dive comes from the action of descending steeply nose-down. Flap comes from the older sense of a hinged piece that moves up and down. Together: hinged panels used during a dive.
Why Pilots Care
They prevent the aircraft from exceeding structural or placarded speed limits, preserving control and avoiding damage.
Analogy
They work like the big air brakes on a truck or the spoilers on a race car that suddenly increase drag to slow things down quickly.
Intuition Check
Do not assume dive flaps are the same as normal landing flaps. Landing flaps help the airplane fly slower for takeoff or landing; dive flaps are used to add resistance and control speed during a steep dive.
Example Sentence 1
The pilot extended the dive flaps before pushing over into the descent to keep the airspeed within limits.
Example Sentence 2
In the jet trainer the dive flaps allowed a stable, controlled pull-out without overspeeding the airframe.