I had a chance to meet Mike Busch, the Savvy Aviator, a couple of weeks ago when people who write for Sport Aviation magazine got together to chat in Oshkosh. I really loved talking to Mike because he and I have written a lot about how badly most piston airplane owners misunderstand the FAA regulations governing maintenance of their airplanes. There just aren’t a lot of rules.
FAR Part 43 is the chapter of the FAA’s rulebook that governs maintenance, rebuilding, and overhaul for all types of aircraft. And it’s the shortest chapter in the entire rulebook – just 17 rules. In contrast, FAR 45, the section governing identification and registration markings of aircraft, has 33 rules. FAR 47, the chapter on how to register an aircraft, contains 71 rules. And FAR chapter 91, the general operating rules, contains hundreds of individual rules.
In fairness, I must note that FAR 43 does have several rather long appendixes that are somewhat specific. Appendix A is important to airplane owners because it lists the preventative maintenance tasks an airplane owner can perform. On the list are things like changing landing gear tires or landing light bulbs, installing new aircraft batteries, and similar routine maintenance.
Overall, for piston-powered airplanes weighing less than 12,500 pounds for takeoff, FAR Part 43 does not include much specific detail about what is required to legally maintain the airplane. It’s a different story for turbine-powered airplanes, or those in the transport category weighing more than 12,500 pounds. For those airplanes very specific and detailed maintenance programs are required. Manufacturers create maintenance plans an owner and his shop can use, or an airplane owner can devise his own maintenance plan and seek approval from the local FAA inspectors.
The basic maintenance requirement for a piston airplane with a standard-category airworthiness certificate is that it undergo an annual inspection. The other maintenance specification that is very clear deals with the transponder and altimeter check every two years. The only other very specific maintenance requirements come from airworthiness directives that can demand inspection, overhaul, modification, or even replacement of any component of the airplane.
What you can’t find in FAR 43 or its appendixes is any mention of TBO. Piston engine makers and the airframe manufacturers who install the engines issue a time between overhaul recommendation, but it has no FAA regulatory force for those of us not flying our airplanes for hire. TBO is a recommendation that you should start thinking about engine overhaul or replacement after the recommended number of flying hours or calendar time has passed, but no special action is required.
Appendix D of FAR 43 lists items that must be checked on an airplane during an annual or 100-hour inspection, but the wording is so vague that it doesn’t provide any real specificity on what passes inspection, and what doesn’t. For example, Appendix D does require a compression check of the engine cylinders. But if the compression is “weak” – which is the word the FAA uses – the inspector is supposed to check for “improper internal condition, or improper tolerances” inside the cylinder. But what is “weak” compression? The FAA doesn’t say. What is an improper “internal tolerance” in a cylinder? That’s up to the inspector, too.
Appendix D repeatedly uses the words “poor condition” to be checked for. What the heck is “poor condition”? Under the rules, “poor condition” is what the mechanic with an inspection authorization (IA) looking at your airplane says it is. Is “poor condition” un-airworthy? I guess it is, because it’s the main thing on the list of Appendix D that an inspector is supposed to look for.
The lack of maintenance regulation leaves mechanics, inspectors, and airplane owners all with a lack of guidance, and with risk. The mechanic and inspector minimize their risk of being blamed for something failing if they replace or overhaul as many parts of the airplane as possible at each inspection. The airplane owner is at risk for spending a huge amount of money that isn’t necessary to keep the airplane reliably airworthy.
I am not saying, nor do I believe, that APs and IAs are dishonest or intentionally run up annual inspection and other maintenance bills. The FAA has simply put them in an almost impossible situation of using their own judgment to determine how much wear is too much. Aircraft and engine manufacturers do create inspections guides with some specific detail on what passes inspection and what fails, but the manufacturers are also in a CYA position. If their inspection guide directs the mechanics to replace or overhaul a component with even minimal wear, they have helped establish an “I warned the owner about that” record that can be used as defense in court if something goes wrong.
The system unintentionally conspires to drive up maintenance costs with no real discernable benefit in flying safety. That’s why Mike Busch has been so successful with his Savvy Aviator seminars that teach pilots about the maintenance rules and how to effectively get the maintenance they need from their shop without paying for unnecessary work.
The best summary of the problem I ever heard was from an experienced IA who said, “I try to tell my young A&Ps that an annual is an inspection and repair only as necessary; it’s not an aircraft restoration.” I wish all shops would follow that direction.
You can become savvy with your aircraft maintenance by watching a Mike Busch webinar every month at 8 p.m. CDT as part of EAA’s webinar series.