The Engine Overhaul Myth

In order to discuss engine overhauls, we should start by looking at a few regulations. FAR 43.2 requires any “person” [defined at FAR 1] that describes a product as being “overhauled” in any required maintenance record [defined at FAR 43.9] to...


In order to discuss engine overhauls, we should start by looking at a few regulations. FAR 43.2 requires any “person” [defined at FAR 1] that describes a product as being “overhauled” in any required maintenance record [defined at FAR 43.9] to have “[used] methods, techniques, and practices acceptable to the Administrator ...” Further, the product must have been “...disassembled, cleaned, inspected, repaired as necessary, and reassembled ...” After reassembly, the product must be “... tested in accordance with [FAA] approved [defined at FAR 1] standards and technical data [read overhaul agency such as a repair station], or in accordance with current standards and technical data acceptable to the Administrator, which have been developed and documented by the holder of the type certificate [read Lycoming or Continental for example]...”

For the sake of argument here let us agree that we are describing an “overhauled” engine, not a factory remanufactured engine. Additionally, there are no such legal overhauls as “top” or “bottom!” These are repairs because there is no data available that complies with FAR 43.2(a) concerning such work.

The first thing aircraft owners often consider when looking for an overhaul agency is if they are rated for the work. An FAA certificated powerplant mechanic can overhaul a complete engine and legally approve it for return to service. In fact, there are a number of engine overhaul shops that aren’t repair stations but rather operate with certificated mechanics.

In the case of shops not operating as a repair station, often the only time the FAA gets involved with an individual mechanic is by specific complaint or an aircraft accident! In the case of problems with an overhaul, the FAA can not proceed against the company, only the individual.

Beware, the company may attempt to lay the blame at the feet of the mechanic who signed off the overhaul. It will cite FAR 43.7 laying the responsibility on the individual because the company is NOT certificated.

On the other hand, a repair station is held co-liable with their employees because FAR 145 requires a repair station to supervise the employees.
Because of this, many owners choose a rated repair station to perform their overhauls. (This does NOT imply that individual mechanics don’t perform quality overhauls!)

To avoid any problems, repair stations and individual mechanics alike should provide customers in writing up front exactly what technical data they intend to use to overhaul the engine. Further, owners may wish to get in writing exactly what minimum parts you will replace AND where you intend to get them from. Are the parts genuine factory parts, or are they going to be PMA parts? If you intend on using PMA parts, be sure to let the customer know up front. Even though use of PMA parts without the owner’s knowledge or consent is absolutely legal with respect to the FARs, it is good practice to let the customer know.

‘Inspected’ and ‘repaired as necessary’
Remember FAR 43.2 and the words “inspected” and “repaired as necessary?” Beware! Inspected and repaired as necessary in accordance with what? In accordance with FAA approved data OR the engine type certificate holder’s data?

FAR 43.9 describes the records required for “maintenance” [defined at FAR 1] which include “inspection, overhaul, repair ... and the replacement of parts.” Is this not what is required when overhauling an engine? You bet it is! The records for an engine overhaul MUST comply with FAR 43.9 for each of these activities. It would be perfectly legal for a certificated person under FAR 43.7 to sign a complete engine overhaul off for return-to-service with the simple statement, “I certify that I overhauled this engine in accordance with the [specific type certificate holder] overhaul manual number [show manual number].” All of the requirements of FAR 43.9 are met, i.e. description of the work performed [overhauled], and reference to [FAA] acceptable data [the TC holder’s overhaul manual].

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