The roles of homebuilders and manufacturers in the USA will be more specific for kit aircraft assembly by the end of the third quarter, as the Federal Aviation Administration's Amateur-Built Aviation Rulemaking Committee issues its final report on the kitbuilding industry.

The study is designed to curb violations of the amateur-build rules, which clearly state that to be classified as home-built, more than half of the assembly must be undertaken by the customer - called the "51% rule".

The report reveals that some companies provide de facto manufacturing facilities for kitbuilt aircraft in which the builder does little actual work, prompting the FAA to issue a moratorium on issuing new kit approvals.

Pilots, industry and FAA officials sat on the committee, which concluded that the role of commercial assistance in excess regulations is too vague. They also decided to update forms to better show who performed fabrication and assembly, and agreed that the kit evaluation process ought to be standardised.

According to the industry trade body, the Experimental Aircraft Association, committee members could not agree on exactly how to define "major portion" of the assembly labour needed for kits.

There will be a public comment period, which EAA expects could be in April or May. Earl Lawrence, vice-president of industry relations for EAA and co-chairmsn of the rulemaking committee, says he understands the FAA's reasons for a moratorium on new kit approvals, but adds: "We're stressing to the FAA that this 'limbo period' should be as brief as possible."