AMC E 640 Pressure Loads

• ED Decision 2007/015/R found in: CS-E Amdt 5 - Engines (Dec 2018)

AMC E 640 Pressure Loads ED Decision 2007/015/R (1) Definitions. For the purpose of [CS-E 640(a)](#_DxCrossRefBm1371447616) the following definitions apply and should be related to the Engine when installed in a typical installation. Normal Working Pressure. The maximum pressure differential likely to occur on most flights including any pressure fluctuations as a result of the normal operation of valves, cocks, etc, where these could produce significant surge pressures. Maximum Working Pressure. The maximum pressure differential which could occur under the most adverse operational conditions (e.g. forward speed, altitude, ambient temperature, Engine speed, use of OEI ratings) likely to be encountered in service, including any pressure fluctuations as a result of the normal operation of valves, cocks, etc., where these could produce significant surge pressures. Maximum Possible Pressure. The maximum pressure differential which could occur under the most adverse combination of operational conditions (e.g. forward speed, altitude, ambient temperature, Engine Speed, use of OEI ratings) likely to be experienced in service, together with Failure of any relevant parts of the Engine or control system, or combinations of Failures which are more likely than Extremely Remote. Consideration should be given to any pressure fluctuations as a result of normal or emergency use of valves, cocks, etc., where these could produce significant surge pressures. Static Parts subject to significant gas or liquid pressure loads. The components subject to high-pressure loads or whose design is influenced by the gas or liquid pressure loads to be contained. Examples might include the compressor, combustor and turbine casings, heat exchangers, bleed valve solenoids, starter motors or fuel, oil and hydraulic system components. Special attention should be given to any filler cap. (2) Static Pressure Tests (see [CS-E 640(a)](#_DxCrossRefBm1371447616)) The anticipated Engine manual serviceable limits may be used as the criteria to judge the acceptability of any permanent distortion. When a test is performed on a part which is subjected in service to a varying pressure throughout its length, it is permissible to simulate the pressure conditions by suitably dividing the part into zones and applying the maximum pressure for each zone including the appropriate factors of [CS-E 640(a)](#_DxCrossRefBm1371447616). (3) Tests. General If the part is subject to loads in addition to those resulting from differential pressure (e.g. flight manoeuvre loads, Engine mounting loads, etc.), an analysis should be made of these additional loads and their effect examined. If the effect of these loads is small it may be possible to simulate them by an addition to the test pressure differential. However, if the loads are of significant magnitude or cannot adequately be represented by a pressure increment the test should be carried out with such loads acting in addition to the pressure loads. The part should be tested at the temperature associated with the most critical stress case or alternatively the test pressure differential may be increased to simulate the loss of relevant properties as a result of temperature. During pressure testing the methods of mounting and restraint by the test facility or test equipment of any critical section should be such as to simulate the actual conditions occurring on the Engine. (4) Analytical Modelling Methods An analytical modelling method may be used to determine adequate strength and fatigue life provided that the model is validated by testing or successful field experience with parts of similar design. [Amdt. No.: E/1]