CS 25J1189 Shut-off means

(See AMC 25.1189)

(a)Each APU compartment specified in CS 25J1181(a) must have a means to shut-off or otherwise prevent hazardous quantities of 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 APU; and

(2)Oil systems for APU installations in which all external components of the oil system, including the oil tanks, are fireproof.

(b)The closing of any fuel shut-off valve for any APU may not make fuel unavailable to the main engines.

(c)Operation of any shut-off may not interfere with the later emergency operation of other equipment.

(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 APU shut-off valve must be located so that the operation of the valve will not be affected by the APU 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.

[Amdt 25/1]