CS-E 520 Strength

(a)The major rotating components of the Engine must have adequate strength to withstand both the thermal and dynamic conditions of normal operation and any excessive thermal or dynamic conditions that may result from abnormal speeds, abnormal temperatures or abnormal vibration loads. In assessing the abnormal conditions to be considered, account must be taken of the Failure analysis prescribed in CS-E 510. (See AMC E 520(a))

(b)Fixed structure in close proximity to rotating parts must be so arranged that any rub caused either by -

(1)Thermal expansion or contraction of parts to the extremes of movement within the operating envelope of the Engine, or

(2)Movement resulting from likely Fault conditions of either the fixed or rotating parts, will occur in a manner not likely to result in a Hazardous Engine Effect. As an alternative, a device giving warning of such unintended movement must be provided.

(c)(1) The strength of the Engine must be such that the shedding of compressor or turbine blades, either singly or in likely combinations, will not result in a Hazardous Engine Effect (e.g. as a long term effect in respect of those Failures which would not be detected by the declared instrumentation, such as vibration detectors) and within the likely shutdown time for those which would be detected, and during any continued rotation after shutdown. (See AMC E 520(c)(1))

(2)Validated data (from analysis or test or both) must be established and provided for the purpose of enabling each aircraft constructor to ascertain the forces that could be imposed on the aircraft structure and systems as a consequence of out-of-balance running and during any continued rotation with rotor unbalance after shutdown of the Engine following the occurrence of blade Failure as demonstrated in compliance with CS-E 810. If the Failure of a shaft, bearing or bearing support or bird strike event, as required under CS-E 800, result in higher forces being developed, such Failures must also be considered, except for bird strike in relation to continued out-of-balance running. (See AMC E 520 (c)(2))

(d)Design consideration must be given to avoiding the risk of major rupture of Engine casings (particularly those which are subjected to high pressure loads) in the event of a local Failure in the casing or damage to the casing arising, for example, from a torching flame following a combustion system Failure.

[Amdt. No.: E/1]

[Amdt. No.: E/2]