PART I - DESCRIPTIVE
parallel which operate if a crash landing occurs.
Operation of these switches also causes the batteries
to be isolated irrespective of the position of the
battery master switch.
(b) Twelve resetting flame detector switches are situated
round the engine and forward part of the jet pipe. Opera-
tion of any of the switches causes the ENGINE FIRE
warning light incorporated in the pushbutton to come on,
provided that electrical power is available. When the
button is pressed the extinguishers discharge their con-
tents through two spray rings, one round the engine
compressor and the other round the turbine nozzle box.
If the fire is extinguished, the light goes out as the flame
(c) The warning light may be tested by operating the switch
(86) on the starboard shelf.
(d) When the battery master switch is OFF the fire-extin-
guishers can be operated only by the inertia switches.
The battery master switch must be ON to test the warn-
ing light or to operate the system by pushbutton.
18. Electrical system (24 volt)
(a) Two 6,000-watt engine-driven generators supply the
whole of the electrical system and charge two 12-volt
aircraft batteries connected in series. Later aircraft will
be fitted with two 24-volt batteries connected in parallel,
thus materially increasing the available reserve should
generator failure occur. The generator failure warning
lights (63) situated below the centre of the instrument
panel, come on only when their associated generator is
not supplying power. Both generators should normally
cut in at 1,800 r.p.m. and cut out at 1,600 r.p.m. but
this will depend on battery condition.
(b) Control of the batteries is effected by a BATTERY
MASTER switch (68) below the centre of the instrument
panel. When set to OFF the switch isolates all electrical
services from the batteries except the engine fire-extin-
guisher inertia switches. When the fire-extinguisher