If you own or operate an aircraft, you probably know that 14 C.F.R. §91.409(a) requires that an aircraft must undergo an annual inspection every twelve calendar months or sooner in order for that aircraft to be airworthy. But once that inspection is complete, what is your mechanic with an inspection authorization ("IA") required to do to document the annual inspection? What maintenance record entry is required and where must that entry be made?
Before we get to those questions, first it is important to understand to what the annual inspection applies. Section 91.409(a) states that an aircraft must receive an annual inspection in accordance with 14 C.F.R. Part 43. When we read Section 43.15(c), which governs annual inspections, we see, and the FAA tells us, that the annual inspection only applies to an aircraft. Specifically, that section requires that the annual inspection of your aircraft be performed using a checklist containing the scope and detail of items contained in Part 43, Appendix D. However, since Appendix D applies to the whole aircraft, including propeller and engine, it is the aircraft itself that receives the annual inspection rather than the individual components. This is true even though the engine and propeller assemblies are also inspected during the course of the annual inspection in accordance with Appendix D, paragraphs (d) and (h).
So, now that we understand the scope of the Section 91.409(a) annual inspection, and that it applies only to the aircraft as a whole, next we need to determine what maintenance record entry is required. 14 C.F.R. § 43.11(a) tells us that a "person approving or disapproving for return to service an aircraft, airframe, aircraft engine, propeller, appliance, or component part after any inspection performed in accordance with part 91 . . . shall make an entry in the maintenance record of that equipment." Since annual inspections apply only to the aircraft, the person who approves or disapproves an aircraft for return to service after an annual inspection is performed must make an entry in the maintenance record of "that equipment," which, according to the FAA, means "the aircraft." Thus, a maintenance entry documenting completion of an annual inspection is required only for "the aircraft."
But, where is your IA supposed to make that entry? In the aircraft's logbook? In a maintenance logbook for equipment other than the aircraft, such as a logbook for the aircraft's propeller or engine? In both? To answer these questions, we need to look at 14 C.F.R. § 91.417 – Maintenance Records.
Section 91.417(a)(1) requires each registered owner or operator to keep maintenance records for each aircraft (including the airframe) and each engine, propeller, rotor, and appliance of an aircraft for the periods specified in Section 91.417(b). But Section 91.417 doesn't say anything about "where" those records are to be kept. The regulation doesn't require you to keep separate or individual records for the required items, nor does it require you to keep all of the maintenance records for the aircraft in a single logbook.
As a result, you may keep one logbook for all of the records for the aircraft and its appliances/components and that is acceptable to the FAA. In that situation your IA would document completion of the annual inspection for the aircraft in that one logbook. Alternatively, it may make sense for you to keep separate or individual logbook records for the aircraft's airframe and appliances/components which then comprise, collectively, the aircraft's records. In that situation, since your IA is only required to document the completion of the annual inspection for the aircraft, your IA may, but is not required to, document the completion of an annual inspection in each of the respective logbooks. This option is also acceptable to the FAA.
In fact, if you maintains multiple logbooks for the aircraft, the FAA suggests that it is probably good practice for your IA to document completion of an annual inspection in each of the respective logbooks. However, if your IA does document the completion of an annual inspection in the maintenance logbook for equipment other than your aircraft, the entry or record in the logbook should be specifically related to that appliance/component. For example, if your IA is going to document the annual inspection in the maintenance logbook for the aircraft's engine, he or she should use language such as "I certify that this engine has been inspected in accordance with an annual inspection and was determined to be in an airworthy condition."
However, it is important to note that this language is different than the language that would be used in the entry that your IA would make in the aircraft's logbook to document completion of the annual inspection and returning the whole aircraft to service rather than its individual components. In that case, your IA would use language referencing the "aircraft" rather than an individual appliance/component such as the engine or propeller. And in both cases the logbook entries would likely contain more detail regarding what was found during the inspection and any maintenance performed on the aircraft or appliance/component.
So, now we know both how and where your IA is supposed to document the annual inspection of your aircraft in order to comply with the regulations and keep the FAA happy. I'll save a more detailed discussion of what should and should not be included in maintenance entries for another day.