Airworthiness Manual Advisory (AMA) No. 549.5

AMA: 549.5
Date: January 3, 1991

Subject: Evaluation Of Amateur-Built Aircraft Kits To Determine Compliance With The Major Portion Requirement

1. Purpose

This advisory information provides an acceptable method for the evaluation of amateur-built aircraft kits to determine compliance with the requirement of Chapter 549 that the major portion of an amateur-built aircraft be fabricated from raw material and assembled by an individual or group of individuals on a non-commercial, non-production basis.

Like all advisory material, this AMA is not mandatory and does not constitute a regulation.  As a guidance document, its purpose is to outline a method of compliance with existing standards.  The applicant may elect to follow an alternate method which must be acceptable to the Department of Transport as a means of compliance with the requirements of Chapter 549 of the Airworthiness Manual.  Hence the terms "shall" and "must" used herein apply only to an applicant who chooses to follow this particular method without deviations.

2. Reference Airworthiness Standards

Chapter 549, Amateur-Built Aircraft, section 549.5.

3. Background And Discussion

An essential requirement for amateur-built aircraft is that "The major portion of the aircraft (more than 50%) is fabricated from raw material and assembled by an individual or a group of individuals on a non-commercial, non-production basis for educational or recreational purposes".  The reasons for this are:

  1. The owner-builder would be serving an informal apprenticeship and be familiar with all aspects of the aircraft construction and assembly and would thus be competent to perform all maintenance on the aircraft.
  2. It would ensure that the aircraft met the original intent that it be built for education and recreation and not circumvent normal certification procedures and become a commercial venture.

Originally, compliance with this requirement caused little or no controversy, since virtually all amateur-built aircraft were constructed from plans only (plans-built).  The builder had no option but to purchase all necessary "raw material", (sheet, tubing, fabric, wood) accessories, etc. from various aircraft vendors and sources.

However, during the 1970's "kits" were being offered to prospective owners/builders that included most, if not all, of the raw material necessary to complete the aircraft.  During subsequent years this trend continued to expand to the extent that many  major components and major sub-assemblies are now included in many such kits, with the view to reducing the man hours necessary to complete the aircraft.  The obvious result of this trend is that many amateur-built aircraft kits are now available whereby it is questionable whether or not the owner/builder is "building" the major portion of the aircraft, or simply assembling the components to complete the aircraft.

Because of the proliferation of these kits and their builder content causing potential conflict with the Major Portion requirement, questions and controversy have frequently arisen with respect to defining what constitutes the major portion of an amateur-built aircraft.  Although major portion has been interpreted as more than 50% of the total aircraft (or airframe) this has proven to be inadequate and more definitive criteria are required.  Interpretations and judgements between different Transport Canada Regional Offices and others who evaluate or review evaluations may vary widely resulting in a lack of uniformity.  This variation is unacceptable and so evaluation procedures must be standardized.

Methodology Used.  Various methodologies or criteria can be used to determine compliance with the Major Portion requirement.  Most of these methodologies are subjective and require the assessor to make judgements to a greater or lesser degree; thus leading to inconsistencies.  However a system based upon a simple parts count or total, as this AMA does, reduces subjective decisions to the minimum.  It also has the advantage of being the simplest system to  utilize to provide consistent and equitable results nation-wide.

The kit evaluation methodology used in this AMA determines the number of parts constructed or assembled by the builder compared with the number of parts constructed or assembled and supplied by the manufacturer.

This methodology is the same as used by the FAA; this commonality then has obvious advantages for airworthiness authorities, manufacturers and builders in both Canada and the U.S.A. (i.e. potential for  mutual acceptance of kit evaluation by the respective airworthiness authorities).

No evaluation methodology is perfect and it is recognized that the one used in this AMA can lead to abuse. Manufacturers can, in order to ensure their content does not exceed the Major Portion requirement, provide a kit that has most labour-intensive parts supplied and have the builder content with many parts that require few manhours to finish.

This AMA provides guidance material to evaluate amateur-built aircraft kits to determine whether they comply with the Major Portion requirement of Chapter 549, (section 549.5, para a). 

Note:  this evaluation should not be confused with the evaluation of amateur-built helicopters and aerobatic aeroplanes (Ref. Chapter 549.101 (C)(2) and 549.201(C), AMA 549/1, AMA 549.101, AMA 549.201)

4. Use Of Checklist (Appendix A)

The checklist at Appendix A may be used:

  1. To determine whether a kit intended for an amateur-built aircraft meets the Major Portion requirement of Chapter 549.
  2. To provide guidance to a kit manufacturer to determine if a proposed kit-built aircraft  meets the Major Portion requirement of Chapter 549.  By use of this checklist it may be determined at the early stages if a kit is eligible for amateur-built approval.  Thus the kit manufacturer may be able to adjust the kit content to meet the Major Portion requirement.
  3. Prior to beginning a kit.  To resolve any controversy with respect to the major portion which may arise in the approval of an amateur-built aircraft under the provisions of Chapter 549.  Questionable cases might be where the aircraft was built from pre-fabricated major components that are readily available from aircraft parts suppliers, or the aircraft was built using major components from previously certified aircraft.

5. Application Procedure:

  1. The responsibility for initiating a request for a kit evaluation normally rests with the kit manufacturer; however, under certain circumstances the kit manufacturer may not be willing, or otherwise able to do this.  In such cases, a prospective owner/builder or other interested party (such as a potential distributor) may act as the applicant and initiate the evaluation request.
  2. The applicant should contact the Regional Director, Airworthiness (RDA) to discuss the project and submit an application for kit evaluation.
  3. The RDA may elect to have the evaluation performed by an organiz­ation acceptable to the Minister or he may have the evaluation performed by RDA staff, or the applicant.  In any event, the evaluation complete with necessary documentation, shall be reviewed and approved or rejected by the RDA and processed as indicated in paragraphs 5(e), (f) and (g).
  4. The evaluation shall normally be performed at the applicant's premises using the checklist and instructions at Appendix A.  The kit should be evaluated in the exact configuration supplied to the owner builder.
  5. If the total checkmarks in the "Builder" column is less than 51% of the total, the kit shall be rejected and the manufacturer so notified.  The kit may however, be reworked by the manufacturer and subsequently re-evaluated.
  6. If the total checkmarks in the "Builder" column is 51% or more of the total, the documentation will be submitted to Transport Canada Aviation (Airworthiness Branch) for approval. 
  7. The documentation shall include:
    1. completed checklist (Appendix A),
    2. a copy of the kit manufacturers parts list, or equivalent, exactly as sold with the kit; and
    3. a recommendation for acceptance as meeting the Major Portion requirement.
    Note:  applicants shall identify each page of the parts list by date and/or revision level.  This will establish the configuration of the kit as evaluated.
  8. Based upon the recommendation of the RDA, Transport Canada Aviation will issue a statement (Appendix B) to the manufac­turer/applicant that the kit meets the Major Portion requirement and is eligible for registration in the amateur-built category.  Kit manufac­turers/ applicants should be aware that any changes to the configur­ation or contents of the kit and parts list may affect the eligibility of the kit and may require a new evaluation.
  9. After an aircraft kit has been found eligible, changes to the kit will be reassessed by the original Regional Office.  Major changes which decrease the amount of fabrication and assembly required by the builder may affect eligibility.  Changes which consist of substitution of materials, parts, fasteners, etc. normally do not affect eligibility.  Derivative models, which are developed from kits previously found eligible, may be determined to be eligible based on inspection and evaluation of the original kit, and evaluation of detailed documentation of the changes submitted by the kit manufacturer.

6. List of Eligible Kits

Maher Khouzam
Chief, Airworthiness Standards
Airworthiness Branch

Appendix A