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Posted 1 years 267 days ago ago by jhadmin

In aviation, there are some topics that never seem to remain settled. For instance, does the responsibility for the inspection and maintenance of an aircraft fall to the owner/operator or the mechanic? Simple. The owner or operator.

However, this hierarchy still gets twisted around occasionally.  The reasons vary on both sides of the fence. They range from simple misinformation or misinterpretation of the FARs to intentional motives in pursuit of an external agenda.

Follow along as we delve into the available guidance and provide a balanced, one-stop-shop approach to who’s in charge of maintaining an aircraft.


The main difference comes down to the regulations. The owner has the regulatory responsibility to ensure the aircraft is maintained in an airworthy condition. The mechanic, on the other hand, only has the regulatory responsibility for the actual performance of any requested inspections and maintenance tasks.

Specifically, the mechanic does not have the authority to walk up to any aircraft and work on whatever he pleases. Even the FAA can’t interact with an aircraft without the owner’s permission, unless it is to affix an Aircraft Condition Notice or investigate an accident.

Another important difference, it’s the owner who has the sole responsibility to select the specific inspection program for aircraft. Not the mechanic. Granted, it would be wise for the owner to consult with a mechanic on which inspection program may be more beneficial, but it falls to the owner to make the selection.

There have been cases where mechanics demanded a certain inspection program based on the premise that it’s their signature on the inspection—not the owners. But in reality, a mechanic can’t demand squat as he has no regulatory authority to select an inspection program for any aircraft he does not own. Period.

Now on the flip side, once the owner decides on the specific inspection program or maintenance task, he cannot dictate how the mechanic performs that work. I know, show me the regulation!


Part 91.403(a) sums up the owner’s responsibility:

The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with part 39 of this chapter.”

The regulation does not provide a method of delegating this responsibility.

Part 91.403(b) expands the rule:

No person may perform maintenance, preventive maintenance, or alterations on an aircraft other than as prescribed in this subpart and other applicable regulations, including part 43 of this chapter.”

It can also be read as follows: No person other than the owner or operator can prescribe the maintenance to be performed on the aircraft.

And Part 91.405 further defines that responsibility:

Each owner or operator of an aircraft— (a) Shall have that aircraft inspected as prescribed in subpart E of this part and shall between required inspections, except as provided in paragraph (c) of this section, have discrepancies repaired as prescribed in part 43 of this chapter.

There are other supporting FARs, but these three regulations squarely place the accountability of the aircraft on the owner. The mechanic is not mentioned anywhere.

On the mechanic side, Part 43.13 and Part 43.15 are the go-to rules. Once an owner gives the mechanic an inspection or task to perform, these regulations provide the necessary regulatory guidance. Also, similarly to the lack of mention of a mechanic in Part 91, the owner/operator is not mentioned in Part 43.

So, there are two separate guidance tracks, each applicable to separate individuals.

On a regulatory side note: There is also a unique difference between Part 43 and Part 91. Part 91 is considered an “operation” rule whereas Part 43 is considered a “performance” rule. The difference?

In order for a Part 91 violation to occur, the owner must operate the aircraft. For example, fly his aircraft with the annual inspection 10 years overdue. Prior to that flight, there’s no violation. However, a mechanic can be held in violation of Part 43 for the work he performed 10 years ago, regardless of the aircraft’s operational history.


So what does this look like in the real world? Let’s say an owner takes his Bell 407 to a different maintenance shop than usual across state for its next scheduled inspection, an annual. The owner faithfully selects Part 43-Appendix D as guidance to perform the inspection, as he’s done for years. The shop manager questions the legality of the selection, but the owner, being well versed in his own right, points to the exception in Part 91.409(e).

Several days later, the lead mechanic calls stating the inspection is complete, but there are several mandatory OEM bulletins that need to be complied before the annual can be signed-off. The owner, a bit less patient now, questions the mechanic to determine which FAA regulation requires the compliance of mandatory bulletins that are not part of an FAA rule such as an airworthiness directive.

By now the conversation has taken a turn for the worse. Even after the owner interjects FAA Order 8260.2A and several FAA Letters of Interpretation into the discussion, which support his point that standalone OEM bulletins are not mandatory--the owner and shop personnel have reached an impasse.  

Doubtful he’ll ever use this shop again, the owner requests the annual be signed off with discrepancies per Part 43.11(a)(5) on an Avery label and that the required list of discrepancies include the aforementioned bulletins. The lead mechanic balks again and wants to enter all write ups and discrepancies in the logbook. Oh, boy. These situations never end well.

After a call to the FSDO, the shop manager presents the owner with the appropriate signed entry labels, hands over the separate list of discrepancies, and parks the completed aircraft on the flight line. Unfortunately, now the owner must get another mechanic to clear the discrepancy list or sign-off a Special Flight Permit so he can fly back home and correct this issue.

So, how did the owner prevail? As we discussed earlier, the owner has the sole authority and responsibility of the aircraft down to the type of work performed. That authority also includes the manner in which the required entries are entered in the aircraft record (Reference Part 91.405(b) and 91.417.) Nowhere do the FARs grant maintenance personnel that same authority.   

I would call this an over-the-top example. Unfortunately, it is actually a composite of several situations that I am familiar with. But it does give you, the reader, a good view on how the regulations work in support of the owner.

However, no matter how this might work in the FAA aviation world, there are some people who flip the regulations for their own agenda. And it’s usually the mechanic and the owner who fall on their heads.


There seems to be an exception to every rule. But… in this case it comes from outside the aviation rules and regulations we discussed above. Enter civil tort litigation.

While most owners and mechanics remain outside this legal process, there are some who get dragged in by no fault of their own. Within tort law, “duty of care” carries a huge weight in determining if a person’s action were negligent.

Simply stated, “duty of care” can be defined as the actions a reasonable person would take in a similar situation. However, it seems that in aviation tort cases a reasonable owner or mechanic exercising their duty of care should second guess or exceed the very rules and regulations that a “normal” owner/operator/mechanic are instructed to strictly follow.

For example, a recent jury verdict placed blame on an owner/operator for not replacing an existing FAA certified fuel tank with an aftermarket “crash resistant” fuel tank because that was something a reasonable owner/operator would have done. It didn’t matter that the accident pilot improperly performed a pre-flight check, skipped a hover check, and left a critical hydraulic switch in the wrong position, directly causing the accident and subsequent fire.

It makes you wonder what a reasonable pilot would have done.

Mechanics are not immune either. There have been several tort cases where mechanics were faulted for not pursuing the compliance of OEM mandatory bulletins on aircraft under their care. As discussed previously, OEM bulletins are not regulatory required, and it is solely up to the owner to decide whether they are complied with.

Yet, in the litigation arena, a reasonable mechanic would research the applicable bulletins—at his own expense—and demand the owner comply with these bulletins or else. Now we learned above where demanding something got a mechanic.

As you can see, regardless of who’s in charge of maintenance and inspection of an aircraft, it will remain an unsettled topic of discussion in certain venues. I guess it all depends on what is reasonable to you.

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