Definition
An FAA airworthiness certification category issued under 14 CFR Part 21.191(g) for aircraft in which the major portion (more than 50 percent) of the fabrication and assembly was performed by a person or persons who undertook the project for their own education or recreation. Aircraft certificated in this category are issued a special airworthiness certificate marked 'Experimental' and are subject to operating limitations that restrict their use, including prohibitions on carrying persons or property for compensation or hire.
Plain English
A special FAA approval given to aircraft that were built mostly by an amateur builder for their own learning or fun, rather than produced by a factory. The aircraft is legal to fly, but with stricter limits on how it can be used.
Context Anchor
Seen when discussing light-sport airplanes that may be factory-built, kit-built, or amateur-built, and when checking whether a specific aircraft may be flown under sport pilot privileges.
Derivation
Experimental' here is a regulatory category name, not a description of how finished the aircraft is. 'Amateur-built' means built by a non-professional for personal reasons (education or recreation), as opposed to a certified manufacturer building to a type design.
Why Pilots Care
Determines the operating limitations, maintenance rules, and flight privileges that apply to the completed aircraft.
Intuition Check
Do not read “experimental” as “unsafe” or “just a prototype.” Here it is an FAA certification category. Do not read “amateur-built” as “poorly built.” Here it means built mainly by private people for education or recreation.
Example Sentence 1
Before flying his neighbor's homebuilt RV-7, the pilot reviewed the operating limitations attached to its Experimental Amateur-Built aircraft certification.
Example Sentence 2
Aircraft operating under Experimental Amateur-Built aircraft certification must follow specific FAA limitations during flight testing.