By Brian Peterson, AOPA Aviation Technical Specialist
With the rising cost and limited variety of new production aircraft on the market, an increasing number of pilots are turning to homebuilt aircraft as an alternative. From the joy of flying your own unique creation, to the pride of completing a difficult construction process, building your own airplane can be one of the most rewarding tasks in aviation.
Make no mistake, though: Building an aircraft is a big job. A large percentage of the kits sold to aspiring homebuilders remain just that — kits — because their owners find the task too demanding. With that in mind, you should first make an honest assessment of the time, space, and money that you are willing to invest in an airplane. Do you have enough room in your garage or hangar? Are you willing to spend a significant amount of money, above and beyond the outlay for the kit itself? Can you, and can your family, afford the time (thousands of hours, in some cases) that it will take to see the project through? If the answer to any of those questions is "no," you'll probably find that you're better suited to owning a production aircraft.
If, on the other hand, you feel that you're up to the challenge, it's time to consider your options. The number and variety of kit- and plan-built aircraft is staggering. From high-performance aerobatic airplanes to sailplanes and auto-gyros — if you want one, you can probably find it somewhere. Once you've settled on a design, make sure that it will suit your needs. Look at its load-carrying capability, range, and speed, and keep in mind that factory specifications are for aircraft built and test-flown by professionals. If at all possible, talk to owners of similar aircraft, and see if they are willing to let you ride along on a flight. If you can't find anyone, look to one of the many owners groups that exist for the more common homebuilts. They should be able to help you as you make your decision and can be an invaluable resource as you delve into the building process.
Once you've made your choice, the real work begins. It's a good idea to start by reading FAA Advisory Circular 20-27, which sets forth procedures for registering and certifying amateur-built aircraft. You should also consider visiting your local FSDO and speaking with an FAA airworthiness inspector. Certification standards vary somewhat with location, and the inspector should be able to tell you what to expect when the time comes to have your aircraft inspected.
One of the most important requirements for the homebuilder is recordkeeping. As you build the aircraft, you are expected to maintain a builder's log detailing the work you perform. The amount of detail required varies, but at the very least, you'll need to construct a step-by-step photographic record of the process, accompanied by explanatory text. If in doubt about the importance of an item, include it. This is not an area in which it pays to take shortcuts.
The builder's log serves two primary purposes. First, it helps the FAA inspector or DAR (designated airworthiness representative — essentially, a person to whom the FAA has delegated the authority to inspect aircraft) verify the quality of your work. Second, it shows that you are in compliance with the so-called "51 percent rule." FAR 21.191 states that experimental certificates can be issued for 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." The FAA has interpreted this to mean that the amateur builder must have performed at least 51 percent of the labor and tasks involved in completing the aircraft. Although it is allowable, under certain circumstances, to enlist professional assistance in building your aircraft, it is NOT legal to hire out the construction job as a whole. Tread carefully here. If the FAA deems that you did not adhere to the 51 percent rule, your aircraft may only be eligible for certification in the extremely limiting experimental-exhibition category. For more guidance on the subject of professional assistance, refer to Advisory Circular 20-139.
As your aircraft nears completion, you should start to think about registration and certification. The FAA recommends that you apply for registration approximately 60 to 120 days before you finish construction. To do this, you will need to provide proof of ownership, an affidavit certifying that you built the aircraft from parts or a kit (you can use FAA Form 8050-88) and an application for registration ( Form 8050-1). Once the aircraft is registered, marked, and completed, you should arrange to have it inspected. Although FAA airworthiness inspectors can do this, most builders find it more expedient to work with a DAR. Your local FSDO can put you in contact with one.
During the inspection, the DAR or airworthiness inspector will verify compliance with the 51 percent rule and make sure that the aircraft is registered and marked properly. He/she will also inspect the aircraft (and your builder's log) to determine that it was constructed using proper techniques and practices, and that it can be operated safely. If your aircraft passes this inspection, you will be issued a special airworthiness certificate and a set of operating limitations. Refer to AC 20-27 for more detailed information on the registration and inspection process.
With the inspection completed, it's time to start the flight-test phase of the project. This will last either 25 or 40 flight hours, depending upon whether you've used a type-certificated engine/propeller combination. During this period, you will be subject to geographical limitations, and you cannot carry passengers. Depending upon your level of experience, you may want to consider hiring a pilot to test-fly the aircraft. Also be aware that the FAA can provide guidance on proper flight-testing methods. Once the requisite test period has been completed, you are free to operate the aircraft normally (subject, of course, to its operating limitations and FAA regulations).
Of course, your aircraft will need to be maintained. In addition to routine maintenance, amateur-built aircraft require an annual condition inspection, which can be performed either by the holder of the repairman certificate for the aircraft or by an A&P mechanic. As the builder of the aircraft, you can apply to the FAA for a repairman certificate — and it's probably a good idea to do so, given the reluctance of many A&Ps to perform condition inspections on homebuilts. Bear in mind, though, that only one person can hold a repairman certificate for a given aircraft. If you co-own the aircraft with others, you will have to decide which of you should apply for the certificate.
One of the more common questions from homebuilders relates to the potential implications of selling their aircraft. Although it is perfectly legal to sell an amateur-built aircraft, the issues that arise from such a sale can be problematic, to say the least. The controlling insight here is simple: As the builder of the aircraft, YOU are its manufacturer. That being the case, there is always the possibility that the person to whom you sell the aircraft — or, perhaps, another owner further down the line — might have an accident and allege negligence on your part. Some suggest that a carefully crafted sales agreement drafted by an attorney can reduce the risk. Others may tell you that the only safe way to sell a homebuilt is to disassemble it and sell the parts to different individuals. The bottom line, though, is that there is no simple solution to the problem. We live in a highly litigious society. If you find yourself needing or wanting to sell your completed homebuilt aircraft, consult an attorney and carefully consider the level of risk with which you are comfortable.
Building an aircraft is a complex enterprise, and we have only been able to touch upon a few of the more prominent issues involved here. Please refer to the remainder of this document for more detail, and remember that there is a tremendous amount of support available to you — from builders groups, kit manufacturers, and the FAA — as you go forward with your project.