Definition
A propeller whose blade pitch angle can be changed only on the ground, while the engine is not running, by loosening the blade clamps or hub fittings, repositioning the blades to the desired angle, and re-securing them. Once set, the pitch remains fixed throughout flight and cannot be altered by the pilot in the cockpit.
Plain English
A propeller you can re-angle the blades on, but only on the ground with tools. Once the blades are set and the aircraft takes off, the angle stays the same for the whole flight.
Context Anchor
Seen in light-sport aircraft discussions, aircraft equipment descriptions, and performance planning.
Derivation
"Adjustable" comes from the Latin juxta, meaning "near" or "to bring close to." The word "ground" specifies where the adjustment happens. Together the term tells you exactly what's possible and where: the pitch can be brought to a new setting, but only while the aircraft is on the ground.
Why Pilots Care
Provides a low-cost way for light-sport aircraft to optimize propeller pitch for specific conditions such as high-density-altitude takeoffs without the weight or complexity of an in-flight adjustable system.
Analogy
Like setting the gears on a bicycle before you start riding—you choose the best setting for the hill ahead but cannot shift once you are moving.
Intuition Check
Do not read “adjustable” as “adjustable whenever the pilot wants.” Here it means adjustable on the ground only, not during flight.
Example Sentence 1
Before the cross-country flight, the owner had the mechanic set the ground adjustable propeller to a coarser pitch to gain a few knots in cruise.
Example Sentence 2
Many light-sport aircraft owners choose a ground adjustable propeller because it offers better efficiency than a fixed-pitch blade at lower cost than a constant-speed unit.