The Elements of Aircraft Maintenance – Part 1

The Elements of Aircraft Maintenance – Part 1

An article by our Guest Blogger and SAS Instructor and Consultant Kevin Rookes

This is the first part of a four-part series that explains what constitutes maintenance from an FAA perspective and what are the differences between the elements that make up maintenance.

The term “maintenance” is defined in Title 14 of the Code of Federal Regulations (14 CFR) part 1, §1.1 as “inspection, overhaul, repair, preservation, and the replacement of parts, but excludes preventive maintenance.”
While this definition has been around for a long time, differences between the five elements that make up maintenance (i.e., inspection, overhaul, repair, preservation, and the replacement of parts) is not always clearly understood. The definition of maintenance does not include the terms “rebuild” or “rebuilt”. Those functions are limited to the Design Approval Holder (DAH) (i.e., manufacturer) with Production Certificate (PC) approval using its approved design data.

Regulatory Background

14 CFR Part 43 identifies persons authorized to perform maintenance and the performance standards that must be followed. If maintenance, preventive maintenance, or alteration are being performed on an aircraft, engine, propeller, or appliance, each person 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 FAA.
A manufacturer is required under § 21.50(b) to prepare a complete set of ICA in accordance with applicable certification standards for the product (14 CFR parts 23, 25, 27, 29, 33, 35) that is acceptable to the Federal Aviation Administration (FAA).
The Instructions for Continued Airworthiness (ICA) enable persons authorized by the FAA to maintain the continued airworthiness of the product and approve the product for return to service. The manufacturer is also required to furnish the ICA to each owner of the product and then make it available to persons requiring its use.
As part of the ICA, the manufacturer is required to provide Airworthiness Limitations as a separate and distinct section (Airworthiness Limitation Section – ALS) from the ICA document. All the certification standards (e.g., parts 23, 25, 33, 35) require the ICA to have an ALS that states the following: “The Airworthiness Limitations section is FAA approved and specifies maintenance required under §§ 43.16 and 91.403 of Title 14 of the Code of Federal Regulations unless an alternative program has been FAA approved.”


There are many different types of inspections. Inspections are generally visual examinations and / or manual checks to determine the condition of an aircraft, product, or article. Inspections can range from general visual inspections, to detailed inspections involving inspection aids such as mirrors or magnifying lenses, to special detailed inspections which may require complete disassembly and/or the use of specialized techniques and/or equipment such as x‑ray, ultrasonic, eddy current, or magnetic particle equipment.
Per the Maintenance Steering Group – 3rd Task Force (MSG-3), ‘General Visual Inspections’ are a visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. ‘Detailed Inspections’ are an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. And finally, ‘Special Detailed Inspections’ are an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. It is also important to understand that inspection is only one element of maintenance; its tasks are different from other elements of maintenance that may be required as a result of performing an inspection, such as parts replacement and repair.

Unscheduled Maintenance

An inspection event can also occur during unscheduled maintenance activities, which would not necessarily be associated with inspecting an aircraft under an inspection program. For example, a reported discrepancy (part 91) or mechanical irregularity (14 CFR parts 121/135).

Use of Instructions for Continued Airworthiness

When an inspection is performed, and a determination of airworthiness is required, Instructions for Continued Airworthiness (ICA) must be used (or other data acceptable to the FAA) as stated in §43.13. ICA must be provided by the manufacturer in accordance with the applicable certification standards.

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