And while it provided supporting definitions to how preventive mx should be looked at, just as major repairs and alterations are via those similar listings, it does not directly translate to a regulatory change. So what it does say is the 31 prevent mx items are considered categories and when combined with review of the Part 1 definition of prevent mx, you can expand on those specific categories but not add new categories.
I disagree with you on that. A pilot or owner reading part 43, Appendix A, paragraph (c) could easily conclude by the plain language of the reg that any task not included in the list is not PM:
"Preventive maintenance is limited to the following work"
AC 43-12A reiterates that restrictive interpretation:
If a task or maintenance function does not appear in the list, it is not preventive maintenance.
The lawyer who wrote Coleal had a rare attack of bureaucratic common sense, and concluded that an all inclusive list would be impossible, so the task list must be
examples:
the lists are better viewed as examples of the tasks in each category-they cannot be considered all inclusive.
OK, cool, problem solved. But owners and pilots should not have to stumble on an obscure 17 year old legal opinion to understand the core meaning of regulatory guidance that directly affects them. The regulation is ambiguously written, and either the reg or the AC should be reworded to clarify the meaning.
Note the Coleal lawyer agrees, since he also wrote:
It is our understanding that Flight Standards' Aircraft Maintenance Division is planning to clarify this issue in a future revision to the AC.
Interesting that this never happened. My speculation is that some old hands in the FAA were unhappy with the lawyer's opinion, and a bureaucratic stalemate exists. Having worked in a federal agency, it is easy to prevent change. Just gum up the internal staffing process with revisions and concerns so it never makes it to the top, unless someone powerful demands progress.