14 CFR 21.191(g) defines an amateur-built aircraft as an aircraft “the major portion of which has been fabricated and assembled by person(s) who undertook the construction project solely for their own education or recreation.” Also called “kit-planes” or “homebuilts,” amateur-built aircraft increase in numbers every year. An amateur-built aircraft is eligible for a special airworthiness certificate in the experimental category for the purpose of operating the amateur-built aircraft. The builder must provide evidence to the FAA that: (1) the “major portion” (more than fifty percent) of the aircraft was fabricated and assembled by an individual or group of individuals; (2) the project is for educational and recreational purposes; and, (3) the aircraft complies with acceptable aeronautical standards and practices. The Special Airworthiness Certificate contains additional limitations restricting operations such a prohibition against carrying persons or property for compensation or hire. 14 CFR § 91.319(a)(2).
The vast majority of amateur-built aircraft are assembled from “kits” designed by a company specializing in such aircraft. Even so, from the FAA perspective, the “manufacturer” of the aircraft is the builder. It is important to note that often an amateur-built airframe is paired with a certificated engine. Engine manufacturers will undoubtedly argue that the installation of the engine in an amateur-built aircraft relieves it of liability for defects due to the fact that the engine was never tested with the airframe by the engine manufacturer, and certified as such.
14 CFR § 103.1 addresses the requirements for an aircraft to be classified as an “ultralight vehicle.” An ultralight is a vehicle that:
(a) Is used or intended to be used for manned operation in the air by a single occupant;
(b) Is used or intended to be used for recreation or sport purposes only;
(c) Does not have any U.S. or foreign airworthiness certificate; and
(d) If unpowered, weighs less than 155 pounds; or
(e) If powered:
(1) Weighs less than 254 pounds empty weight, excluding floats and safety devices which are intended for deployment in a potentially catastrophic situation;
(2) Has a fuel capacity not exceeding 5 U.S. gallons;
(3) Is not capable of more than 55 knots calibrated airspeed at full power in level flight; and
(4) Has a power-off stall speed which does not exceed 24 knots calibrated airspeed.
Ultralight vehicles are not required to meet airworthiness certification standards and a pilot’s license is not required to fly an ultralight vehicle. Ultralight vehicles have numerous prohibitions about when and where they can fly, listed in 14 CFR § 103 et, seq. Attorneys at Krutch Lindell have investigated cases where ultralight vehicles which have been modified in ways that take them out of the ambit of Part 103. For example, adding a larger fuel tank to an ultralight may take the operator from full compliance to being an unlicensed pilot flying an unairworthy and illegal aircraft.