Saab 340B, Руководство по эксплуатации

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ICE AND RAIN PROTECTION
Description
Aircraft Operations Manual
11.1
PAGE 4
Jun 01/17
2.2.3 Upper and Lower Duct
(Applicable to A/C with COX intakes
(with mod no. 2095 installed)
The upper duct and the lower duct, including the
particle separator and exhaust nozzle, are each
provided with four thin film resistor type temperature
sensors whereof two in each group are used as pri-
mary sensors and two as back
− up temp sensors.
The sensors are connected to the Anti − ice Control
Unit (ACU) which in turn is divided into two identical
and independent microprocessor control channels
for heating power regulations, both in normal and
back
− up mode.
The ACU further includes fault monitoring and sys-
tem test functions, it also contains a Control Unit
Display (CUD) for degradation indications and two
test/reset buttons. The CUD and buttons are lo-
cated in the nacelle and is provided for mainte-
nance trouble shooting purpose, however, when
any indication light in the CUD is activated, the re-
spective side INTAKE L/R Maintenance Light in the
TEST 3 panel is activated, provided the aircraft is
on ground and is controlled by the WoW switches.
It shall be observed that shutting down an engine or
setting one AC generator switch to OFF while the
ENGINE ANTI
− ICE is ON will result in the L or R
INTAKE maintenance light to come ON. The only
way to reset the light is by the reset buttons in the
nacelle.
− With Mod. No. 2250 the INTAKE L/R Mainte-
nance Light in the TEST 3 panel is disconnected.
− With Mod. No. 2255 the INTAKE L/R Mainte-
nance Light in the TEST 3 panel is removed.
On basis of the temperature information from the
primary temp sensors, the two microprocessor con-
trol channels in the ACU supply time proportional
modulated AC power to the thermo
− wire heaters in
the upper and lower duct.
A failure in the inlet ice protection system is indi-
cated by L or R INTAKE light in the ENGINE anti
−
ice panel coming on. The light comes on regardless
of, if the ENGINE ANTI
− ICE is switched ON or not.
The light comes on if:
− Loss of more than:

one primary sensor
or

one back − up sensor
or

one primary and one back − up sensor
in one duct section (upper or lower)
− Loss of DC power.
− Loss of AC power, total or partial
− An over − temperature is sensed resulting in dis-
connection of the primary microprocessor. Heat
control will be maintained by the back
− up proces-
sor.
− An under − temperature is sensed resulting in dis-
connection of the primary microprocessor. Heat
control will be maintained by the back
− up proces-
sor.
− Failure of one or more heater elements.
− loss of primary or one back − up or one primary
and one back − up temp sensor in one duct sec-
tion (upper or lower). Anti − icing is still controlled
by the primary micro processor.
2.2.4 Split Lip
The split lip and inlet guide vanes are heated by
bleed air ported from the 5th compressor stage via
an engine anti
− ice valve. A failure in the system is
indicated by L or R AIR light coming on.
The light comes on if:
− The Electronic Solenoid Valve does not close
when ENGINE anti
− ice is switched OFF.
− The Electronic Solenoid Valve does not open
when ENGINE anti
− ice is switched ON.
Using engine anti − ice also illuminates L/R ENG
ANTI − ICE (blue) lights located on the flight status
panel. These lights come on whenever respectively
L or R ENGINE anti
− ice switch is turned on. The
lights indicate that the system has been switched
on but give no indication of correct operation of the
system.
2.3 Propeller de − icing (Fig. 3)
The propeller blades are equipped with boots which
are electrically heated from the 115 V AC wild fre-
quency buses. The system is controlled by a switch
for each propeller with positions OFF
− NORM − MAX.
Incorporated in the system are indications and cau-
tion lights as follows: