Nuts, Bolts, and Electrons: Assessing Mechanical Risks — GA maintenance issues

An Aircraft with Inop Items

by Jennifer Caron, FAA Safety Briefing

If you are an aviation maintenance technician (AMT), can you return to service an aircraft that has inoperative items? The quick answer is yes — and MEL will explain why.

What is a MEL?

If you’re the typical AMT, you are very familiar with MEL. MEL is the Minimum Equipment List for an individual operator’s inoperative items, non-essential for safe flight. It derives from the Master MEL, and is specific for a particular make and model aircraft by serial and registration number. MEL lists all the equipment on an aircraft type that can be inoperative at the time of flight, and is the regulatory authorization that permits operation of the aircraft with certain inoperative equipment.

The anatomy of MEL is found in Title 14 of the Code of Federal Regulations (14 CFR) part 91, wherein the FAA considers the MEL as a supplement to the aircraft’s type design. This supplement, called a Supplemental Type Certificate (STC), is the approved modification to the aircraft’s existing type certificate by which an aircraft is considered airworthy. It is a major change in type design not great enough to require a new application for a type certificate. An example of this would be the installation of a powerplant different from what was included in the original type certificate.

Under part 91, the FAA considers the MEL as an STC. Therefore, under an approved MEL, the aircraft may be operated under all applicable conditions and limitations contained in the MEL.

Bottom line: a mechanic can return to service an aircraft with inoperative items under an approved MEL.

Can I Fly?

And it’s the owner/operator, not the mechanic, who is responsible for determining the aircraft’s maintenance status. However, this in no way reduces the responsibility of certificated mechanics or repair stations for maintenance functions or tasks they perform or supervise. Especially when it comes to any additional or repetitive maintenance that is required under the MEL.

And although the pilot in command is ultimately responsible for determining the condition of the plane as safe for flight, the AMT shares in that responsibility and makes decisions and choices about maintenance, as does the pilot on go/no-go scenarios.


The satisfactory accomplishment of all maintenance procedures, regardless of who performs them, is the responsibility of the owner/operator. But all in all, the AMT is the central figure in aviation maintenance, and along with the owner/operator, plays an equally important role in aviation safety.

Learn More

This article was originally published in the January/February 2017 issue of FAA Safety Briefing magazine.

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