§25.1189 Shut-off means

(See AMC 25.1189.) (a) Each engine installation and each fire zone specified in CS 25.1181 (a)(5) must have a means to shut off or otherwise prevent hazardous quantities of fuel, oil, de-icer, and other flammable fluids, from flowing into, within, or through any designated fire zone, except that shut-off means are not required for – (1) Lines, fittings, and components forming an integral part of an engine; and (2) Oil systems in which all compo-nents of the system in a designated fire zone, including the oil tanks, are fireproof or located in areas not subject to engine fire conditions. (b) The closing of any fuel shut-off valve for any engine may not make fuel unavailable to the remaining engines. (c) Operation of any shut-off means may not interfere with the later emergency operation of other equipment, such as the means for feathering the propeller. (d) Each flammable fluid shut-off means and control must be fireproof or must be located and protected so that any fire in a fire zone will not affect its operation. (e) No hazardous quantity of flammable fluid may drain into any designated fire zone after shut-off. (f) There must be means to guard against inadvertent operation of the shut-off means and to make it possible for the crew to reopen the shut-off means in flight after it has been closed. (g) Each tank-to-engine shut-off valve must be located so that the operation of the valve will not be affected by powerplant or engine mount structural failure. (h) Each shut-off valve must have a means to relieve excessive pressure accumulation unless a means for pressure relief is otherwise provided in the system.