It's an age-old question among us maintenance technicians, one that is yet to receive a clear, understandable answer from the FAA. I still remember the first time I raised the question to my chief inspector. At that time I was not interested in trying to find the answer in the regulations, I expected the chief inspector to be able to provide me with a quick response so that I could move on and get to the next task at hand (hoping the whole time for a minor repair). What I learned that day has remained the same to this day. The distinction between a major alteration and a minor alteration and the major repair and a minor repair is clouded by outdated regulations and guidance material.
Let's jump in with both feet. First of all, we need to understand the difference between a repair and an alteration. Although not specifically defined in the regulations, a repair is maintenance that takes place to restore a type-certificated product to "condition for safe operation." However, an alteration is maintenance that is performed that adds to and/or removes from the type-certificated product's configuration. So it is obvious to see that repairs and alterations make up the majority of what maintenance is performed on aircraft every day.
Next, let's try to understand the reason that we care about the difference between major and minor. For one thing, 14 CFR Part 43.9 in harmony with Appendix B to Part 43 mandates a different means of recording the maintenance when it is considered "major".
14CFR Part 43.9 (a)(4)
"If the work performed on the aircraft, airframe, aircraft engine, propeller, appliance, or component part has been performed satisfactorily, the signature, certificate number, and kind of certificate held by the person approving the work. The signature constitutes the approval for return to service only for the work performed. In addition to the entry required by this paragraph, major repairs and major alterations shall be entered on a form, and the form disposed of, in the manner prescribed in Appendix B, by the person performing the work."
14 CFR Part 43 Appendix B (a)
"(a) Except as provided in paragraphs (b), (c), and (d) of this appendix, each person performing a major repair or major alteration shall -
(1) Execute FAA Form 337 at least in duplicate;
(2) Give a signed copy of that form to the aircraft owner; and
(3) Forward a copy of that form to the local Flight Standards District Office within 48 hours after the aircraft, airframe, aircraft engine, propeller, or appliance is approved for return to service."
The next question to consider is who is it that has to make the decision whether the repair or alteration is major or minor. Well, this takes us back to the rule that requires execution of the FAA Form 337, 14 CFR Part 43.9.
14 CFR Part 43.9 (a) (4) (in part)
"...In addition to the entry required by this paragraph, major repairs and major alterations shall be entered on a form, and the form disposed of, in the manner prescribed in Appendix B, by the person performing the work."
You see, it is the person performing the work who makes the distinction. When the work is performed, the person performing that maintenance must decide whether or not a "form prescribed in Appendix B" must be utilized. Since the person who performs maintenance is the person who makes the distinction, it's only natural that we look to who can perform maintenance on aircraft in the first place and thus find out who is burdened with this heavy load. Look at 14 CFR Part 43.3.
43.3 Persons authorized to perform maintenance, preventive maintenance, rebuilding, and alterations
"(a) Except as provided in this section and § 43.17, no person may maintain, rebuild, alter, or perform preventive maintenance on an aircraft, airframe, aircraft engine, propeller, appliance, or component part to which this part applies. Those items, the performance of which is a major alteration, a major repair, or preventive maintenance, are listed in Appendix A.
Consider this: Is it a major repair/alteration or simple replacement?
Major or Minor? That is the question Joe Hertzler A repair is maintenance that takes place to restore a typecertificated product to "condition for safe operation." And, an...
In Part 2 of my tome on field approvals, we will cover current field approval policy found in Change 16 to FAA Order 8300.10.