All of us are aware that the aircraft we fly must have an airworthiness certificate. Usually this certificate will be a Standard Airworthiness certificate issued when the aircraft is manufactured. What about experimental airplanes that are constructed by an individual? Do you have to have an airworthiness certificate on board that type airplane? What does the word “experimental” mean when used in reference to aircraft? We hear “experimental” used within the sport aviation industry on a regular basis. The most common use of the word “experimental” applies to a classification of an airworthiness certificate used for an amateur-built airplane. This is different from the airworthiness category assigned to an airplane that is mass-produced by a manufacturer and then sold to the general public. The answer to the above question is yes, you must have an airworthiness certificate on board your experimental aircraft. Experimental aircraft are issued a Special Airworthiness certificate under the experimental category. Experimental airworthiness certificates are issued for different purposes. These purposes are: (1) research and development, (2) to conduct flight tests to show compliance with airworthiness regulations, (3) crew training (4) exhibition, (4) for air racing, (5) to conduct market surveys and sales demonstrations, (7) to operate an amateur-built airplane, (8) operate primary kit aircraft, (9) operating light sport aircraft.
The two most common purposes for which experimental certificates are issued are for exhibition and for amateur-built operation. Let’s begin by discussing the exhibition purpose. The exhibition category is somewhat restrictive pertaining to the operation of the aircraft. The purpose of this category is to allow the operator to participate in several different activities. The regulation, FAR 21.191 (e) defines this category as “Exhibiting the aircraft’s flight capabilities, performance, or unusual characteristics at air shows, motion picture, television, and similar productions, and the maintenance of exhibition flight proficiency, including (for persons exhibiting aircraft) flying to and from such air shows and productions.” The intent of this airworthiness category is not to use the airplane for normal purposes such as taking your friends or family out for an evening flight.
Certificating an aircraft under the amateur-built purpose is another matter. An experimental certificate for amateur-built purposes clearly allows the holder of the certificate to operate the aircraft for just about any purpose other than for commercial use. The regulation pertaining to amateur-built status is FAR 21.191 (g) that states “ Operating an aircraft the major portion of which has been fabricated and assembled by persons who undertook the construction project solely for their own education or recreation.”
What does this mean to an aircraft builder? First of all, understand that if we build an airplane we must have it inspected by a FAA inspector who then issues the airworthiness certificate. The FAA inspector or a Designated Airworthiness Representative (DAR) inspects the aircraft using FAA Order 8130.2C as a guide. The inspector must ensure that the aircraft is indeed airworthy in addition to checking the compliance with several other factors. One of the most significant issues the inspector must investigate is whether or not the builder complied with FAR 21.191 (g). Reviewing this regulation I will restate it using my own emphasis on certain words. “Operating 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.” Notice that there is not a provision allowing us to hire someone else to build the airplane for us and we then certificate it under the amateur-built status. We must build (assemble and fabricate) 51% or more of the airplane and do so for our own education or recreation. If we elect to contract a person or company to build our airplane then we can only certificate it as an experimental under one of the other purposes such as exhibition. The majority of builders do not want to be in any experimental category other than amateur-built because of the restrictions that apply. Notice also that the regulation provides us with the latitude to have more than one person build the airplane. As a matter of fact, any number of people may build the airplane as long as compensation is not received.
It should be noted that the FAA does not overly regulate the building of custom aircraft. FAR 21.191 (g) is one of few regulations that directly pertain to building your own airplane. You are not required to abide by FAR Part 23 that defines airworthiness standards for aircraft. You can use any design, any material, etc. in the construction of your airplane. You will, of course, use good judgement during the construction process and the FAA inspector will be sure that you have used acceptable building materials and techniques prior to issuing the airworthiness certificate. With this in mind, the FAA inspector (using FAA Order 8130.2C) will ask you to prove through your builders’ log that you did build the major portion of the airplane for your own education and recreation. This will be validated prior to issuance of the airworthiness certificate. FAA Order 8130.2C states very clearly that “Aircraft which are manufactured and completely assembled as a business for sale to other persons are not considered to be bon fide amateur-built aircraft.” It goes on with the following bold warning: “ NOTE: Amateur-built kit owner(s) will jeopardize eligibility for certification under FAR 21.191(g) if someone else builds the aircraft.”
The question then is can the builder of a custom aircraft seeking certification as an amateur-built contract any work on the airplane? The answer is found in Advisory Circular 20-139. This circular outlines the FAA’s position regarding commercial assistance during the construction of amateur-built aircraft. This Advisory Circular defines commercial assistance as “Assistance in the building of an amateur-built aircraft in exchange for compensation. This does not include one builder helping another.” It also defines major portion “As related to a special airworthiness certificate issued for the purpose of operating amateur-built aircraft, major portion means that when the aircraft is completed, the majority of the fabrication and assembly tasks have been performed by the amateur-builder(s) who submit the application for certification.”
A valid question is “what does the FAA use to determine whether or not I have complied with the regulations pertaining to amateur-built status?" The answer is found in AC20-139. A checklist pertaining to the various parts and components of the airplane defines the major portion. This checklist is FAA Form 8000-38. This checklist has recently been revised so I recommend every potential builder acquire a copy. It is found within the Advisory Circular. It lists virtually every part of the airframe and asks the kit manufacturer to place a checkmark next to each item defining whether the kit manufacturer or the amateur builder accomplishes the task. So the major portion rule is not based on time, finances, etc., rather on component parts of the aircraft. After the kit manufacturer completes all of the checkmarks found on the list if the total under the kit manufacturer column is 49% or less then that particular kit is placed on the FAA’s Listing of Eligible Amateur-Built Aircraft Kits. If the kit is on this listing and is then assembled in accordance with the kit manufacturer’s assembly manual, you will have no difficulty proving to the FAA inspector that you have completed 51% or more of the construction. A detailed “Builders’ Log” is also necessary to further substantiate your 51% involvement.
Can you legally hire anything at all? Of course you can. There are a number of items of construction that are not a part of FAA Form 8000-38. Examples are painting, upholstery, avionics installation, fabrication of hardware items such as fittings, wheels and brakes, etc.. These tasks or processes are not required to be personally completed by the amateur-builder. You can attend a workshop such as the EAA SportAir workshops to learn proper procedures and building techniques. You can hire a lot of difficult tasks and inspections to be completed professionally. The bottom line is that you must complete 51% or more of the tasks listed on the checklist. The kit manufacturer should be able to provide you with a copy of this checklist as it pertains to their airplane.
In summary, you have to work at abusing the major portion rule. If you assemble your kit aircraft according to the provided instructions you will certainly fall within the legal contexts of the regulation. Plan’s built aircraft obviously have little difficulty in meeting the major portion rule. You can certainly abuse FAR 21.191(g) by having a professional builder totally construct your airplane and then trying to certificate it as an amateur-built. By the way, you are required to sign a notarized legal document (FAA Form 8130-12, Eligibility Statement Amateur-Built Aircraft) where you legally certify that you have built 51% or more of the airplane for your own education and recreation. Before you have someone build your airplane take a look at the fine print on this form. You will find it under “NOTICE” and it outlines the penalty for falsification of the form.