ED Decision 2018/014/R
(1) More than one type of fuel may be allowed: CS-E 560(a) applies to each type and covers additives in the fuel (for example, fuel system icing inhibitor).
Some Engines may use other fluids, such as water methanol: when appropriate, the word "fuel" in CS-E 560 should be interpreted as covering these fluids as well.
If the Engine may be adversely affected by a parameter of the fuel specification, such as sulphur or gum content, this should be identified in the appropriate documentation.
When defining the fuel specifications under CS-E 560(a), CS-E 90 should also be considered for effects induced in the fuel system by the fuel itself, fuel additives or water in the fuel.
(2) To comply with CS-E 560(b)(1), contaminants likely to be present in the fuel delivered to the Engine from the aircraft should be considered, as well as contaminants resulting from wear of a part or component of the Engine fuel system (such as fuel pump bearing).
(3) In compliance with CS-E 560(e), any means provided for protection against icing in the fuel system may either be in operation continuously or commence operation automatically when required.
(4) In
compliance with CS-E 560(d) and (e), the applicant should consider the effect
on Engine operability of the transient fuel icing conditions likely to be
encountered in service. In the absence of a completed threat assessment by the
aircraft manufacturer, the applicant should make an assessment of the
potential threat, or declare that no capability has been demonstrated. The
limitations on the demonstrated capability, any related assumptions, and
potential effects on operability should be documented in the Engine
installation manual, as required under CS-E 30(a) and CS-E 20(d). This should
include but should not be limited to the quantity of ice, and the fuel
temperature at the critical conditions for transient fuel icing. The
compliance evidence should address the possibility of a blockage of Engine
fuel system components, and the consequences of the resultant activation of
any bypass features, under the minimum fuel heating conditions and with the
worst-case Engine-to-Engine variability.
Note: A transient fuel icing condition is considered to be a short-duration exposure to high concentrations of (water) ice in the fuel delivered to the Engine that is caused by the accumulation and subsequent shedding of ice within the aircraft fuel system.
(5) In complying with CS-E 110(d), because a fuel leakage is considered as a potential fire hazard, design precautions should be taken to minimise the possibilities of incorrect assembly of fuel system components, including pipes and fittings, especially if parts of the system have to be removed during the routine maintenance procedures.
(6) For compliance with CS-E 130(a), in order to minimise the possibility of occurrence and spread of fire, each filter or strainer should be mounted so that its weight is not supported by the connecting lines or by the inlet or outlet connections of the filter or strainer, unless adequate strength margins under all loading conditions are provided in the lines and connections.
(7) Each filter or strainer requiring regular servicing should -
— be accessible for draining and cleaning or replacement;
— incorporate a screen or element that is easily removable; and
— have a sediment trap and drain except if the filter or strainer is easily removable for drain purposes.
(8) Any restriction in bypass operation condition should be specified in the appropriate manuals.
(9) CS-E 560(g) is intended to cover any likely changes in settings caused by vibrations, incorrect maintenance, mechanical interference when installed or during handling, etc. Examples of design precautions are: locking devices, sealing, inaccessible installation.
[Amdt No: E/1]
[Amdt No: E/5]
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