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Section 11 Testing of Powerplants After Overhaul

4-1601    GENERAL. This section provides guidance to ensure that powerplant overhaul facilities accomplish the testing of powerplants after overhaul per the maintenance procedures recommended by the engine manufacturer.

A.    Manufacturer Recommended Procedures. Powerplant manufacturers are very specific in their recommended procedures for powerplant testing after overhaul. This testing is required to run‑in new parts, check powerplant performance, and check the quality of the work performed during overhaul. The procedures to be followed in overhaul testing of a powerplant vary by make and model, but are clearly outlined in the manufacturer’s manual.

B.    Practices Acceptable to the Administrator. Title 14 of the Code of Federal Regulations (14 CFR) part 43, § 43.13 requires that each person performing maintenance must use methods, techniques, and practices acceptable to the Administrator. If special equipment or test apparatus is recommended by the powerplant manufacturer, that equipment or apparatus (or an equivalent acceptable to the Administrator) must be used.

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C.    Certificated Repair Stations. Title 14 CFR part 145, § 145.109 requires repair stations to possess the equipment, tools and materials required to perform maintenance in accordance with part 43, to include § 43.13. Repair stations performing powerplant tests required by § 43.2 after overhaul must ensure the methods, techniques and practices prescribed in the current manufacturer’s maintenance manual, or instructions for continued airworthiness (ICA) prescribed by the manufacturer, or other methods, techniques and practices acceptable to the Administrator, are used. The testing may be performed by the repair station itself or may be accomplished by an outside maintenance organization, as allowed by § 145.217. The repair station will be responsible for the final acceptance of the tested engine if the maintenance organization performing the test did not issue an approval for return to service per § 43.9.

D.  Outside Agencies Performing Overhaul Testing. A certificated repair station may utilize an outside maintenance organization to perform the required testing after overhaul provided:

·    The agency that is to perform the test has the information necessary to complete the test properly;

·    The powerplant records will be maintained per § 145.219;

·    That until the required test procedures have been completed by a person authorized by § 43.7, the powerplant has not been tested and is not considered airworthy; and

·    The person authorized by § 43.7 is responsible for the final acceptance of the tested powerplant.

E.    Powerplant Overhaul Testing Environment.

1)    Turbine Engine Testing. Since the performance of a turbine engine is greatly affected by the surrounding atmospheric conditions, most turbine engine manufacturers recommend that powerplant testing after overhaul be accomplished in the controlled conditions of a test facility/cell equipped as outlined in the manufacturer’s overhaul manual.
2)    Reciprocating Engine Testing. The manufacturers of reciprocating engines allow the airframe to be considered a suitable test stand for the running‑in of overhauled engines, provided the following requirements are observed:

·    A test club is used in place of a flight propeller;

·    A suitable cooling shroud or scoop is used to gather and direct cooling air over the cylinders;

·    A cylinder head temperature pickup is installed on each cylinder to monitor individual cylinder temperature; and

·    All necessary calibrated gauges are installed independent of the aircraft gauges.

3)    Additional Testing Methods. When other methods for testing come to the attention of aviation safety inspectors (ASIs), the methods should be evaluated to determine if they are equivalent to the previously stated requirements. When noncompliance with § 43.13 is evident, corrective action must be initiated to correct any discrepancies.
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NOTE:  When performing an engine overhaul, especially if it includes any kind of engine modification, all of the work must be accomplished in accordance with approved data.

RESERVED. Paragraphs 4‑1602 through 4‑1620.