Advisory 

Circular 

Subject: COMMERCIAL ASSISTANCE 

DURING CONSTRUCTION OF 

AMATEUR-BUILT AIRCRAFT 

Date: 413196 AC No: 20-139 

Initiated by: AIR-200 Change: 

1. PURPOSE. This advisory circular (AC) explains current Federal Aviation Regulations (FAR) and 

Federal Aviation Administration (FAA) policy for the fabrication and assembly of amateur-built aircraft. 

It provides information and guidance to persons involved in the construction of amateur-built aircraft, the 

manufacture of kits designed to be assembled into aircraft by amateur-builders, builders of aircraft 

fabricated from plans for certification as amateur-built, and persons providing assistance to amateurbuilders, Like all AC material, this AC is not mandatory and does not constitute a regulation. It is issued 

for guidance purposes and to outline a method of compliance with the applicable FAR. In lieu of 

following this method without deviation, a person may elect to follow an alternate method, provided the 

alternate method is also found by the FAA to be an acceptable means of complying with the requirements 

of the FAR. Since the method of compliance presented in this AC is not mandatory, the terms “shall”and 

“must” used herein apply only to a person who chooses to follow this particular method without 

deviation. This AC does not change regulatory requirements and does not authorize changes in, or 

deviations from, regulatory requirements. 

2. RELATED FEDERAL AVIATION REGULATIONS, FAA ADVISORY CIRCULARS AND 

FAA ORDERS. 

a. 14 CFR part 21, Certification Procedures for Products and Parts. 

b. 14 CFR part 65, Certification: Airman other than Flight Crewmembers. 

c. Advisory Circular 20-27, Certification and Operation of Amateur-Built Aircraft. 

d. Advisory Circular 65-23, Certification of Repairmen (Experimental Aircraft Builders). 

e. Advisory Circular 90-89, Amateur-Built Aircrafl and Ultralight Flight Testing Handbook 

f. FAA Order 8130.2, Airworthiness Certification of Aircraft and Related Products. 
AC 20-139 413196 

3. BACKGROUND. 

a. The FAR provides for the issuance of a special airworthiness certificate in the experimental 

category for the purpose of operating amateur-built aircraft. Title 14 CFR part 21, section 21.191(g), 

defines an amateur-built aircraft as “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” (emphasis added). 

b. The FAA, in partnership with the Experimental Aircraft Association (EAA) and the Small Aircraft 

Manufacturers Association (SAMA), saw a need to address the practice of fabrication and assembly of 

amateur-built aircraft for profit. The aircraft were designed as kits and/or plans-built, with the intent that 

they would be constructed by amateur-builders for their own education or recreation. 

4. DEFINITIONS. As used in this advisory circular, the following definitions apply: 

a. Aircraft Evaluation. The evaluation performed for the purpose of determining if a specific 

amateur-built aircraft meets the major portion requirement of section 21.191 (g). 

b. Builder Center. A place where amateur-builders can obtain instruction, help, and support during 

construction of their aircraft. 

c. Commercial Assistance. Assistance in the building of an amateur-built aircraft in exchange for 

compensation. This does not include one builder helping another. 

d. Compensation. Payment by the amateur-builder applicant in cash, services, or other tender, to 

any person who provides assistance on a commercial basis in the building of an aircraft. 

e. Checklist. The FAA Form 8000-38, Fabrication/Assembly Operation Checklist, is used by the 

FAA as an aid in determining if a manufacturer’s aircraft kit meets the major portion requirements of 

section 2 1.19 1 (g). It is also used for determining if a completed aircraft is eligible for certification as an 

amateur-built aircraft (sample in appendix 1). 

f. Kit-Built Aircraft. An aircraft that is constructed from a manufactured kit that may include some 

major sub-assemblies and/or pre-assembled components. 

g. Kit Evaluation. An evaluation by the FAA to determine if an aircraft built from, and according 

to, the kit instructions will meet the major portion requirement of section 2 1.19 1 (g). 

h. Letter of Eligibility. A letter provided by the FAA to an aircraft kit manufacturer advising that 

the aircraft kit requested to be evaluated meets the major portion requirement of section 2 1.19 1 (g). 

i, Major Portion. As related to a special airworthiness certificate issued for the purpose of 

operating amateur-build 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. 

2 Par3 
4/3/96 AC 20-139 

j. Person. An individual, firm, partnership, corporation, company, association, joint-stock 

association, or governmental entity. It includes a trustee, receiver, assignee, or similar representative of 

any of them. 

k, Plans-Built Aircraft. An aircraft that is constructed exclusively from plans/blueprints without 

the aid of purchased major sub-assemblies orpre-assembled kit components. This also includes aircraft 

of a builder’s original design. 

I. Unacceptable Commercial Assistance. Any commercial assistance that reduces the work 

performed by the amateur-builder to less than the major portion of the aircraft construction. 

5. EVALUATION OF KITS, COMPLETED KIT-BUILT, AND PLANS-BUILT AIRCRAFT. 

The evaluation to determine compliance with the major portion construction requirement of the FAR is 

usually performed by an FAA Aviation Safety Inspector (ASI) from a Manufacturing Inspection District 

Office (MIDO) or a Flight Standards District Office (FSDO). Additionally, a Designated Airworthiness 

Representative (DAR) may be authorized to evaluate a completed plans-built aim& intended for 

certification as an amateur-built. 

a. Initial Evaluation of Kits. 

(1) Aircraft kit manufacturers requesting a kit evaluation should submit a letter to the local FAA 

,Manufacturing office. The purpose of the evaluation is to determine if the completed aircraft is capable 

of meeting the major portion requirements of section 2 1.191 (g). 

(2) When the kit is evaluated using the checklist as a guide and found to comply with the major 

portion requirement of section 21.191 (g), a Letter of Eligibility is sent to the kit manufacture. The kit is 

then acceptable to be included in the Listing of Eligible Amateur-Built Aircraft Kits. This letter 

SHOULD NOT be construed to mean the kit or its manufacturer is FAA certified, certificated, or 

approved, and it is not appropriate to represent i as such. 

(3) The listing is published by the FAA’s Engineering and ManutXcturing Branch, AFS-610, P.O. 

Box 25082, Oklahoma City, OK 73 125, telephone number, (405) 954-4103. This information is also 

available in electronic format through. Fed World in Springfield, VA by calling (703) 487-4608 or 

through the internet via: httpJJwww.fedworld.govJ. The purpose of the listing is to assisthe amateurbuilder, the ASI, or the DAR by eliminating the duplication or evaluations for the major portion 

determination. 

(4) If the kit manufacturer later offers an option or makes changes to the kit that decreases the 

amount of fabrication and assembly required by the builder, the manufacturer should request a new 

Letter of Eligibility. The kit manufacturer would provide a revised checklist and a description of the 

option or change to the FAA with drawings and/or photos as necessary. If the FAA determines that the 

revised kit still meets the major portion requirement,he FAA will issue a new Letter of Eligibility for 

the amended checklist without conducting a physical inspection or complete re-evaluation of the kit. If 

the FAA determines that the option or change was of sufficient magnitude, a physical inspection and reevaluation of the kit will be performed. 

Par4 3 
AC 20-139 413196 

b. Completed Kit-Built Aircrrift. When a kit has been evaluated and published in the listing of 4 

eligible amateur-built aircraft kits, and no commercial assistance was used in the construction of the x 

aircraft using the evaluated kit, the AS1 or DAR will not be required to make another major portion rule 

determination for the completed aircraft. 

c. Plans-Built Aircraft. 

(1) During final inspection for compliance with section 21.191 (g), a plans-built aircraft must be 

evaluated using the FAA Form 8000-38 as a guide. If the builder intends to utilize commercial 

assistance, the FAA Form 8000-38 can be submitted to the FAA prior to construction, listing the tasks or 

processes for which the commercial assistance is proposed. It should also show the intended fabrication 

and assembly tasks the builder will perform. On the basis of this pre-construction checklist, a builder of 

a plans-built aircraft should be able to obtain an evaluation in writing from the AS1 or DAR of the effect 

that the proposed commercial assistance will have on the major portion requirement for the completed 

aircraft. 

(2) A person may provide commercial assistance to a builder of a plans-built aircraft or nonevaluated kit. This assistance or task must be listed in the KIT MANUFACTURER column on the 

checklist when the completed aircraft is presented for evaluation/certification to the AS1 or DAR. 

6. COMMERCIAL ASSISTANCE NOT REQUIRING RE-EVALUATION OF THE 

COMPLETED AIRCRAFT. 

a. Commercial instructional assistance may be obtained by the amateur builder in the fabrication or 

assembly of specific parts and the completion of certain tasks or processes involved in the construction 

of the aircraft. During all instructional activity, the amateur-builder must be present to accomplish the 

tasks and all subsequent fabrication and assembling of parts for which commercial instruction is being 

rendered. Tasks completed by the amateur-builder would be identified on the FAA Form 8000-38 under 

AMATEUR or in the assembly manual. For example, assume fabrication of the wing ribs is listed on 

the checklist or in the assembly manual as a task required to be completed by the amateur-builder. 

Instructional activity could be provided to build the first few ribs with the remainder to be completed by 

the amateur-builder. 

b. Commercial assistance may be obtained for non-checklist items on a kit that has been evaluated 

by the FAA. A non-checklist item is a task or process that is not listed in the checklist. These items also 

include painting and the installation of interior upholstery or avionics beyond basic regulatory 

requirements. Such a task or process would not be required to be personally completed by the amateurbuilder for the aircraft to receive an airworthiness certificate under section 21.191(g). 

c. The amateur-builder is not expected to have fabricated every component that makes up the 

completed aircraft. Non-checklist items include the fabrication of the engines, propellers, wheels and 

brake assemblies, and standard aircraft hardware. The installation of these items may be required to be 

accomplished by the builder if they are checked in the AMATEUR column on the checklist. 

7. Commercial Assistance Requiring Re-evaluation of the Completed Aircraft. If commercial 

assistance other than that described in paragraph 6 is performed on the items listed in the checklist under 

4 Par5 
AC 20-139 

AMATEUR, on a evaluated kit, the major portion evaluation previously performed by the FAA 

will be invalid for that specific aircraft project. Consequently, itmay result in a complete re-evaluation 

of the fabrication and assembly of that aircraft. This could put the amateur-built status of the aircraft in 

jeopardy. In other words, the aircraft will be treated as a non-evaluated kit and subject to complete 

evaluation by the FAA when presented for certification as an amateur-built aircraft. The builder may 

want to obtain a pre-construction evaluation of proposed commercial assistance in writing from the AS1 

or DAR to preclude certification problems at the completion of a project. 

8, Commercial Assistance on Incomplete Aircraft. Commercial assistance does not include the 

instance where an incomplete aircraft is sold to another builder and the second or subsequent builder 

completes the aircraft. In such a case, the work performed by the first builder will count toward 

completion of the major portion by the second builder. The second or subsequent builder should obtain 

as much detailed information and documentation, e.g., logbooks, material receipts, pictures, etc., from 

the original builder as possible. This information will be helpful in the FAA’s determination for the 

major portion requirement of the aircraft and eligibility of the subsequent builder to meet the 

requirement for repairman certification under section 65.104. The second builder may not be eligible for 

a repairman certificate under section 65.104, unless it can be shown to the satisfaction of the FAA that 

the individual has the requisite skill to determine whether the aircraft is in a condition for safe operation. 

9. Non-Evaluated Kit Aircraft. An aircraft constructed from a non-evaluated kit must be evaluated 

upon completion for compliance with section 21.191 (g), ,by the AS1 or DAR using the procedures in the 

FAA Order 8 130.2, Airworthiness Certification of Aircraft and Related Products, and the 

FAA Form 8000-38, as a guide. 

10. ADDITIONAL INFORMATION. The FAA Form 8 130- 12, Eligibility Statement, is one of the 

forms required to be submitted by the applicant for a special airworthiness certificate for the purpose of 

operating an amateur-built aircraft. It includes sections for the registered owner and aircraft information 

along with the applicant’s declaration certifying that all statements and answers are complete and true. It 

also provides notice of the potential penalty that could be applied if false or fraudulent statements are 

made. A sample of the FAA Form 8 130-12 is located in appendix 2. 

11. INFORMATION SUPPLIED BY INDUSTRY TO PROSPECTIVE CUSTOMERS. Kit 

manufacturers are encouraged to include a document explaining the intent and purpose of the 

amateur-built rule in their information packages. Prospective customers would then be made aware of 

their responsibility and limitations under the FAR. The information package should summarize the 

process used to determine kit eligibility and the inspection of the completed aircraft. It should also 

advise potential builders of the statement they must sign certifying that they fabricated and assembled 

the major portion of the aircraft. Additionally, the customer should be advised of the need for and the 

availability of flight training, as well as the value of participation in the EAA Flight Advisor Program. 

12. INFORMATION SUPPLIED BY INDUSTRY TO PURCHASERS. Kit manufacturers are 

encouraged to include a copy of the amateur-built regulation and to advise the purchaser of the 

requirement for the applicant to certify that they fabricated and assembled the major portion of the 

aircraft for their own education or recreation. In addition to the aircraft assembly manual, the kit 

manufacturer should reference this AC regarding acceptable commercial assistance and the use of a 

builder center for help and instruction during construction of an aircraft. The manufacturershould 
AC 20-139 4/3/96 

inform purchasers of the help available to them through various EAA programs, including: EAA 

Chapters, Technical Counselors, and Flight Advisors. 

Frank P. Paskiewicz 

Acting Manager, Production 

and Airworthiness Certification Division 

Par 12 
413196 AC 20-139 

Appendix 1 

APPENDIX 1. PREPARATION INSTRUCTIONS FOR 

FAA FORM 8000-38, FABRICATION/ASSEMBLY 

OPERATION CHECKLIST 

1. PURPOSE. This appendix provides instructions for completing FAA Form 8000-38. 

A sample form is included as figure 1. 

2. GUIDANCE. This form may be used by any person to establish the eligibility of an aircraft 

to be certificated experimental, for the purpose of operating as an amateur-built. Prepare the 

form as follows: 

a. Enter the company name and address, aircraft model, (by name and/or number), document 

name and date (manufacturer’s parts list, assembly manual, etc., with latest revision) and type of 

aircraft (land, sea, fixed-wing, rotorcraft, etc.). 

b. Mark the specific tasks required to fabricate and assemble the aircraft. Mark, an “x” 

under the column heading “Accomplished By” in the appropriate space when the task is 

performed by the AMATEUR. If the task is performed by the kit manufacturer or by a person 

providing commercial assistance, a mark will be placed in the KIT MANUFACTURER column. 

Additional blank lines are provided to list any tasks not on the checklist. If a task is listed and 

not applicable to the construction of the aircraft enter N/A in the appropriate space. 

c. Use the comments area to enter any additional comments, information or statements, as 

necessary. 

d. Print or type name of person performing the evaluation of the kit or aircraft. 

e. The person performing the evaluation of the kit or aircraft should sign their name in the 

signature block. 

f. Enter the date the evaluation was performed. 
AC 20-139 

Appendix 1 

413196 

FIGURE 1. SAMPLE FAA FORM 8000-38, FABRICATION 

ASSEMBLY OPERATION CHECKLIST 

Aircraft Model Document Name and Date 

FM Form WOO-38 W9t1 Page : 
413196 

FIGURE 1. SAMPLE FM FORM 8000-38, FABRICATION 

ASSEMBLY OPERATION CHECKLIST (CONT'D) 

AC 20-139 

Appendix 1 
AC 20-139 

Appendix 1 

FIGURE 1. SAMPLE FAA FORM 8000-38, FABRICATION 

ASSEMBLY OPERATION CHECKLIST (CONT'D) 

413196 
413196 AC 20-139 

Appendix 1 

FIGURE 1. SAMPLE FAA FORM 8000-38, FABRICATION 

Asmanx OPERATION CHECKLIST (CONTW 

I 8. Dynamically Track and Balance Tail Rotor System 

5 
AC 20-139 

Appendix 1 

FIGURE 1. SAMPLE FAA FORM 8000-38, FABRICATION 

ASSEMBLY OPERATION CHECKLIST (CONT'D) 

4/3/96 

Fabrication/Assembly Operation Checklist (Continued) 

1. Fabricate Instrument Panel 

COCKPIT/INTERIOR 

Accomplished By 

Kif Manufacnw I Amateur 

1 I 

2. Install Instrument Panel and Instruments 

3. Fabricate Seats 

4. Install Seats 

5. Fabricate Electrical Wirino, Controls/Switches 

6. Install Electrical System Controls/Switches 

Zomments 

TOTAL 

. 

%nced Name Stgnarure Oale 

Page 

6 
413196 AC 20-139 

Appendix 2 

APPENDIX 2. PREPARATION INSTRUCTIONS-FOR 

FAA FORM 813042, ELIGIBILITY STATEMENT 

AMATEUR-BUILT AIRCRAFT 

1. PURPOSE. This appendix provides instructions for completing FAA Form 8130-12. 

A sample form is included as figure 1. 

2. GUIDANCE. This form is required to be submitted by a person applying for a special 

airworthiness certificate, experimental, for the purpose of operating an amateur-built aircraft 

under section 2 1.19 1 (g). Prepare the form by inserting in: 

a. SECTION I. REGISTERED OWNER INFORMATION: Enter the name, 

address, and telephone number for residence and place of business. 

b. SECTION II. AIRCRAFT INFORMATION: Enter the model (number and/or name), 

assigned serial number, registration number, whether aircraft was fabricated from a plan or kit, 

engine make, engine serial number, prop/rotor make, prop/rotor serial number. 

c. SECTION III. MAJOR PORTION ELiGIBILITY STATEMENT OF APPLICANT: 

The name of person(s) (printed), identified in Section I that certify the aircraft identified in 

Section II on the form was fabricated and assembled for their own education or recreation. The 

applicant should sign (in ink), and enter the date signed. 

d. SECTION IV. NOTARIZATION STATEMENT: The signature, date, and stamp (if 

applicable), of a Notary Public who witnessed the signature of the applicant. 
4/3/96 AC 20-139 

Appendix 2 APPENDIX 2. SAMPLE FAA FORM 8130-12, ELIGIBILITY 

STATEMENT AMATEUR-BUILT AIRCRAFT 

Form APIWOW 

O.M.B. N0.2120-001 

ELIGIBILITY STATEMENT 

AMATEUR-BUILT AIRCRAFT 

Instr~~t~~ns~ Prrnt or type all mlormatlon except slgnsture. Submit 

ongmal to an authorlzad FAA representatwe. Appkant COmpletOl 

Sectton I tnru III Notary Pubhc Completes Sectlon IV. 

I. REGISTERED OWNER INFORMATION 

Uame(r) 

It. AIRCRAFT INFORMATION 

Jodel Engine(s) Make 

Wgned Serial No. Engme(s) Sertal No.(s) 

G3gistrrbon No. Prop./Rotor(r) Make 

kratt Fabricated: Plan 0 Kit c! Prop.lAotor(s) Serlal No.(s) 

Ill. MAJOR PORTION ELICIBILITV STATMENT OF APPLICANT 

I certify the aircraft identified in Section II above was fabricated and assembled 

for my (their) education or recreation. I (we) have records to support this statement and will 

make them available to the FAA upon request. 

- NOTICE - 

Whoever in any matter within the jurisdiction of any department or agency of the United States 

knowingly and willfully falsifies, conceals or covers up by any trick, scheme. or device a 

material fact, or who makes any false, fictitious or fraudulent statements or representations, or 

makes or uses any false writing or document knowing the same to contain any false, fictitious 

or fraudulent statement or entry, shall be fined not more than S10.000 or imprisoned not more 

than 5 years, or both (U.S. Code, Title 18. Sec. 1001.) 

APPLICANT’S DECLARATION 

I hereby certify that all statements and answers provided by me in this statement form are 

complete and true to the best of my knowledge, and I agree that they are to be considered part 

of the basis for issuance of any FAA certificate to me. I have also read and understand the 

Privacy Act statement that accompanies this form. 

jignature of Applicant (In Ink) ( Date 

1 

IV. NOTARIZATION STATEMENT 

CM Form SlsQ-12 wdw 

2