Definition
An aircraft constructed by an individual builder from a set of detailed drawings and instructions, with the builder sourcing or fabricating most or all of the raw materials and components themselves rather than receiving them as a pre-packaged kit.
Plain English
An aircraft someone builds at home from a set of plans, gathering or making the parts as they go, instead of buying a ready-to-assemble kit.
Context Anchor
Seen in discussions of light-sport and amateur-built aircraft, especially when comparing factory-built, kit-built, and plans-built airplanes.
Derivation
Plans' here refers to the engineering drawings and construction instructions provided by the aircraft designer. 'Plans-built' simply means the aircraft was built from those plans, distinguishing it from a kit-built aircraft (where parts come pre-cut and packaged) or a factory-built aircraft (built complete by a manufacturer).
Why Pilots Care
Affects certification path, builder liability, and how the aircraft is inspected under experimental or light-sport rules.
Analogy
It is like building a small boat from blueprints instead of assembling a boxed kit. The plans guide the shape and structure, but the builder still has to gather, make, and fit many of the pieces.
Intuition Check
Do not read "plans-built" as meaning the aircraft was built for a planned trip or according to a flight plan. Here, "plans" means the construction drawings used to build the aircraft.
Example Sentence 1
His plans-built aircraft took nearly seven years to complete because he had to fabricate most of the metal parts himself.
Example Sentence 2
Chapter 17 notes that plans-built aircraft follow different regulatory paths than kit-built models.