AMC E 170  Engine systems and component verification

ED Decision 2007/015/R

The intent of CS-E 170 is to define the additional tests or analysis which would be necessary for those systems or components which are not necessarily tested during the endurance test of CS-E 440 or CS-E 740.

It is also recognised that the other specifications of CS-E do not always provide sufficient testing to cover all the conditions (pressure, temperature, vibration, etc.) which could affect the airworthiness of a piece of equipment throughout the declared flight envelope and within all the declared installation conditions.

Other reasons for testing under CS-E 170 include, but are not limited to, the following examples:

—         When testing is required in support of CS-E 50(a) for validation throughout the declared flight envelope and within all the declared installation conditions.

—         When a pressure relief valve, in the inlet manifold of a turbocharged Engine, and the effect of its operation on the Engine and turbocharger are untested during the scheduled test of CS-E 440.

—         When, for example, an over-speed protection system (or a torque limiter) is unlikely to be tested during the scheduled tests of CS-E 740.

—         When an Electronic Engine Control System has a mechanical back-up which is not normally used during the endurance test.

—         When demonstration that a Failure indicating system, on which dependence is placed in the Engine safety analysis, will function satisfactorily when required.

The Engine manufacturer should define all necessary testing and / or analysis for those accessories or systems that need specific substantiation, in addition to the certification tests performed on a complete Engine, with attention paid to their location and operating conditions. Unless it is necessary to test the functioning of a system itself, substantiation of individual components can be made separately from the system they are part of.

The objective of CS-E 50(a), in conjunction with CS-E 80 or CS-E 170, is to demonstrate that the Engine Control System can perform its intended function in its installed environment. In particular, Electronic Engine Control Systems are sensitive to lightning and other electromagnetic interference and these conditions can be common to more than one Engine. Advisory material for environmental effects other than lightning and electromagnetic effects can be found in AMC E 80.

If, for compliance with CS-E 170, high intensity radiated fields (HIRF)/Lightning tests are carried out on anything other than a representative complete Engine, the test results may depend on the validity of the assumed electrical bonding between those elements of the Engine that are tested and the main Engine earth. In such cases, the applicant should demonstrate that these electrical bonding assumptions are valid.  This may be accomplished by examination of the type design drawings, electrical continuity checks, or actual inspection of a representative Engine.

For compliance with CS-E 170, the functional integrity of the Engine Control System should be maintained when subjected to designated levels of electric or electromagnetic induction, including effects from external radiation and lightning. The environment, including radiated and conducted emissions, to which the Engine Control System and its components are qualified should be entered into the Engine instructions for installation, and is considered to be an installation limitation for the installer.

When the installer specifies the environmental conditions of the installation, compliance with this specification may be demonstrated by meeting the specified installation specifications.

When the installation specifications are not specified or not known, environmental conditions of a typical installation may be assumed.

It should be established by analysis or test that all components of the Engine Control System, including all electronics units, sensors, harnesses, hydromechanical elements, and any other relevant elements or units, operate properly in their declared environment. The environmental limits are not imposed by the rules, but should be representative of the environments that are expected to be encountered in the Engine installation.

Additional means may be found in AMC E 80 or in AMC 20-1 and AMC 20-3 for Electronic Engine Control Systems.

In meeting the above environmental concerns, due consideration should be given to dispatching in each approved degraded state.

See AMC E 80 for additional specific means.

[Amdt. No.: E/1]