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Ultralight to Experimental-Amateur Built: How to Convert

I currently own an ultralight, am a licensed pilot and would like to convert my ultralight to an Experimental Aircraft. Is this possible?

Yes. FAA Advisory Circular (AC) 103-7 addresses how to certificate an ultralight as an aircraft (reprinted below).

Does FAA Advisory Circular 103-7 apply to converting an “ultralight trainer”?


AC 103-7 says I can certificate it as Experimental Exhibition or Experimental Amateur-Built. What is the difference?

An Experimental-Exhibition airworthiness certificate is not very useful because your aircraft will be limited to take offs and landings only from your home airport! The only exception is if you are flying (directly) to an exhibition that you have registered with the FAA (in advance).

An Experimental, Amateur-Built aircraft, once past the flight test phase, can operate under normal FAR Part 91 rules with very few other restrictions on the airworthiness certificate. The main restriction is that it cannot be used for “commercial purposes” (no rental).

I bought the aircraft completed and ready to fly from a dealer. Can I qualify as Experimental Amateur-Built?

No, the majority of the aircraft was not built by an amateur for recreational or educational purposes. In this case you would only qualify for the more restrictive Experimental Exhibition category.

What is a builder’s log and why do I need one?

The builder’s log is simply a record of construction of the aircraft. It usually has some photos of the builder working on the aircraft.

The reason the builder’s log is so important is that to qualify for Experimental Amateur-Built certification the aircraft must have been built by amateur builder(s) for recreational or educational purposes (FAR 21.191(g)). A builder’s log provides the documentation that an amateur built the aircraft for recreational and/or educational purposes.

If I don’t have a builder’s log, can I still certificate the aircraft as Experimental, Amateur-Built?

Maybe. If you can get the amateur builder to provide you with an affidavit that the aircraft was amateur-built you may be able to convince the FAA. It is recommended that you discuss this in advance with the FAA FSDO handling the conversion. However, life will be much easier with the builder’s log.

What paperwork must be submitted to make the conversion?

Basically, the same paperwork required to get an experimental amateur-built.

Will I be able to apply for a Repairman Certificate that will allow me to do my own annual condition inspections the converted aircraft?

Yes, assuming you are the “primary builder” of the aircraft. In addition, you will have to apply using form FAA Form 8130-6.

If you did not build the aircraft then you will be required to have an Airframe & Powerplant mechanic perform the inspection and sign off.

The following is the guidance provided by the FAA in Advisory Circular 103-7



This section outlines the regulations which are applicable to the operation of ultralights as certificated aircraft and provides general information regarding how to comply with the regulations.


A person who chooses to operate an ultralight as a certificated aircraft has two options for airworthiness certification of the vehicle, depending primarily on the configuration of the vehicle or kit when purchased, as follows:

a. Completely Assembled at the Factory, or Assembled by the Purchaser From a "Bolt Together" Kit With Little or No Fabrication Operations. An ultralight in this category would be eligible for airworthiness certification only for the purpose of exhibition in the experimental classification. Application for an experimental certificate for exhibition may be made to the nearest Flight Standards field office.

b. Major Portion (Over 50%) Fabricated by the Builder / Purchaser, Either from Raw Materials to the Builder's Own Design or From a Partially Prefabricated Kit. A vehicle shown to meet the provisions of this category would be eligible for airworthiness certification as an amateur built aircraft, in addition to eligibility for experimental exhibition. Detailed information pertaining to amateur built aircraft requirements are in FAA Advisory Circular 20-27E, Certification and Operation of Amateur Built Aircraft. Applications for such certification may be made to the nearest Flight Standards field office.


An ultralight that is to be certificated and operated as an aircraft is subject to the registration and marking requirements applicable to aircraft. The applicant should contact the nearest Flight Standards field office to obtain the required forms and information concerning the procedures to be followed. Advisory Circular 20-27E also contains information concerning registration and marking requirements as they apply to amateur built aircraft.


Part 61 of the Federal Aviation Regulations contains the regulations which define the certificates and ratings which pilots must hold to function as a pilot of a certificated aircraft in the United States. It also outlines the minimum experience levels and standards to qualify for those certificates and ratings. The minimum levels of pilot currency for certain operations are also contained in Part 61.


Part 91 contains the general operating rules (Subpart A), flight rules (Subpart B), and maintenance rules (Subpart C) which are applicable to all certificated aircraft operations. Pilots of certificated ultralight aircraft must comply with Part 91. No certificated aircraft can be operated under Part 103. The flight rules of Subpart B are the minimum standards for flight operations except where the operating limitations of the particular aircraft establish more stringent standards. The majority of the rules contained in Subpart A and Subpart C will not apply to operations of certificated ultralight aircraft; however, a thorough review of these regulations should be conducted to determine those applicable to a particular type of ultralight aircraft.

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