CS 25J997 Fuel strainer or filter

For essential APUs: There must be a fuel strainer or filter between the fuel tank outlet and the inlet of either the fuel metering device or an APU driven positive displacement pump, whichever is nearer the fuel tank outlet. This fuel strainer or filter must:

(a)Be accessible for draining and cleaning and must incorporate a screen or element which is easily removable;

(b)Have a sediment trap and drain except that it need not have a drain if the strainer or filter is easily removable for drain purposes;

(c)Be mounted so that its weight is not supported by the connecting lines or by the inlet or outlet connections of the strainer or filter itself, unless adequate strength margins under all loading conditions are provided in the lines and connections; and

(d)Have the capacity (with respect to operating limitations established for the APU) to ensure that APU fuel system functioning is not impaired, with the fuel contaminated to a degree (with respect to particle size and density) that is greater than that established for the APU in CS-APU 250.

[Amdt 25/1]