Part 43: Our Rule: Written by mechanics for mechanics

Of the 199 Parts and a zillion words that make up FAA regulations in Chapter 1 of Title 14, Aeronautics and Space in the Code of Federal Regulations, only one Part speaks solely to us


Of the 199 Parts and a zillion words that make up FAA regulations in Chapter 1 of Title 14, Aeronautics and Space in the Code of Federal Regulations, only one Part speaks solely to us, mechanics. Part 43 is that rule. It sets the requirements for what kinds of U.S. registered aircraft we can work on, who can work on the aircraft, who can sign off the aircraft’s logbook; it defines our performance rules and record keeping.

If you permit me to wax metaphorically, Part 43, Maintenance, Preventive Maintenance, Rebuilding and Alteration, is one of the three core regulations or foundation stones that set the standards for our aviation industry. The other two are Part 21, Certification Procedures for Products and Parts, and Part 91 General Operating and Flight Rules. These three rules achieved "star status" because they are the only regulations identified on the FAA Form 8100-2 Standard Airworthiness Certificate. But star status aside, what is even more amazing is the fact that Part 43 contains only 13 rules and six appendixes. That is all the regulation it takes to set the airworthiness maintenance requirements for performing work on 185,000 U.S.-registered aircraft.

43.13: Performance Rule

For the next three minutes of your time, I would like to cover just one rule in Part 43. It’s section 43.13, Performance Rule. I picked this rule because it uses only three paragraphs to set the standards for the work we perform. It is also the one rule that is quoted 95 percent of the time in the Letter of Investigation sent by the FSDO to some hapless mechanic who is accused of noncompliance of the regulations.

The rule, section 43.13 Performance rules (general), is an old rule going back almost 60 years. It even predates the FAA and the Federal Aviation Regulations (FAR). How can I tell? Easy, the rule number 43.13 has an odd number suffix. When the FAA took over from the Civil Aeronautics Administration on April 1, 1958, the FAA immediately began to re-codify the old Civil Aviation Regulations into the new FAR format. Even back in the good old days, any new rulemaking had a lot of legal hoops to jump through. So it is not surprising that it took eight years until all the rules were changed over. So in August of 1966 all of the re-codified FAR Parts were identified with odd numbers and each individual rule or section had an odd number suffix. So tomorrow, as you thumb through the FARs in quest of a loophole and you find an even number part, like Part 36 or an odd part with a even number suffix rule like, 43.2, now you know it means these parts and rules were added to the FAR sometime after August of 1966.

You ’shall’ use current data and adequate tools

Now to the rule! FAR 43.13 contains three paragraphs. Paragraph (a) contains two requirements. The first requirement for a person performing maintenance on an aircraft or appliance is that they "shall" use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness prepared by the manufacturer, or other methods, techniques, and practices acceptable to the Administrator, except as noted in section 43.16. Note that the first paragraph sets the tone for the rule. It uses the word "shall." This is a word with hair on its chest because "shall" is used as an imperative and not in the permissive sense as in words like "should" or "may." So the rule requires the mechanic to have current data from the manufacturer or other data acceptable to the Administrator. This reference to other acceptable data allows the mechanic to use data similar to FAA AC 43.13-1B and 2A to work on older aircraft like J3-cubs, and 7 AC Aeroncas that never had a manufacturer’s maintenance manual. The rule’s one exception speaks to section 43.16 Airworthiness Limitations. This rule allows a mechanic to perform maintenance that is called out in an air carrier’s FAA approved operations limitations or an inspection program approved under section 91.409(e). Note that an old rule (43.13) references a new rule (43.16), so 43.13 was revised at the same time 43.16 became effective.

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