Definition
A protective hydraulic valve in a wing flap system that automatically blocks flap extension or retraction when airloads on the flaps exceed a preset limit, preventing structural damage to the flap system from operation at excessive airspeeds.
Plain English
A safety valve that stops the flaps from moving when the air pushing on them is too strong, so the flaps and their mechanism don't get damaged.
Context Anchor
Seen in aircraft maintenance discussions of flap systems, especially when checking why flaps will not extend normally or why flap movement stops under high air loads.
Derivation
Overload' literally means 'too much load.' The valve responds when the aerodynamic load on the flaps becomes too great, so it acts as the system's overload protection.
Why Pilots Care
Protects the aircraft from structural damage and loss of control that could occur if flaps are extended beyond their speed limits.
Analogy
It works like a pressure relief feature on a machine: when the force gets too high, it gives the pressure another path instead of letting the machine damage itself.
Intuition Check
Do not read “overload” as an electrical overload or as too much weight in the airplane. Here it means too much force on the flaps from the air or from the flap system itself.
Example Sentence 1
When the pilot selected flaps down above the limit speed, the flap overload valve blocked hydraulic flow until the airspeed was reduced.
Example Sentence 2
If the pilot extends the flaps above the recommended speed, the flap overload valve may open to safeguard the structure.