Saab 340B, Руководство по эксплуатации

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ICE AND RAIN PROTECTION
Description
Aircraft Operations Manual
11.1
PAGE 6
Jun 01/17
NORM power will be applied whenever the aircraft
is on ground (WOW, weight on wheels switches
sensing ground mode).
A/C 300 − UP
The side windshields heating can be selected ON or
OFF. When set to ON, power is applied gradually
by the controller to reduce thermal stresses in the
windshields.
2.5 Windshield wipers (Fig. 5)
Each front windshield is provided with a windshield
wiper. The wipers can be operated both at HIGH
and LOW speed. Also, each wiper rotary switch has
a PARK position where the wiper is returned to
stowed position.
The wiper motors have a thermal overheat protec-
tion with auto
− reset when the temperature has de-
creased.
2.6 Pitot tubes, Outside Air Temperature
probe (OAT) and angle of attack sensor
heating (Fig. 5)
The pitot tubes, temperature probe (OAT) and angle
of attack sensors are electrically heated. All except
the standby pitot tube are supplied with 115 VAC,
wild frequency. The standby pitot tube is supplied
with 28 VDC.
There is a main pitot tube and an angle of attack
sensor on each side of the airplane in the cockpit
area. These tubes and sensors are heated whenev-
er the 115 VAC wild frequency buses are powered.
The temperature probe located forward of the pilots
windshields is also powered directly from the 115
VAC wild frequency system but via the WOW
switch, powering the probe only in the air. A heated
probe without any air flow would give an incorrect
temperature reading.
The standby pitot tube, powered by 28 VDC, is con-
trolled by a STBY PITOT switch which must be in
ON position for the pitot tube to be heated. The pi-
tot tube must be powered for 5 minutes to be pro-
vide with full anti
− ice protection.
2.7 Ice detector
(Optional Mod No. 1933)
The ice detector consists of an ultrasonic axially
vibrating tube as sensing element. The logic is con-
trolled by a micro
− processor built into the ice detec-
tor housing. Upon sensing ice as evident by a
change in frequency, at a preset level, the micro
−
processor will activate the L and R ENG ANTI − ICE
blue status lights which will start flashing. When
switching ENG A/I ON the blue light will change to
steady.
The ice detector has a heating element which will
de
− ice the detector in a cyclic manner. When the
frequency of vibration is sensed to be at a ”no ice”
level the heating is switched off and a new ice
detection cycle is started. If the ENG ANTI
− ICE has
been switched ON previously, and remains ON, the
blue status lights will remain steady, i.e. the flashing
is suppressed.
The INVERTER must be in INV 1 position for the
ice detector to work, unless Mod No. 2546 is
installed, when the Ice detector is powered from R
AC GEN BUS and will then work regardless of in-
verter selection.
IT IS VERY IMPORTANT TO UNDERSTAND
THAT THE ICE DETECTOR ALERT SHALL
NOT BE USED AS THE CUE FOR SWITCHING
ON ENG ANTI
− ICE. THE ICE DETECTOR
FUNCTION SHALL BE CONSIDERED AN
ALERT SHOULD ICING CONDITIONS BE EN-
TERED UNNOTICED FOR ANY REASON.
CAUTION
2.8 Ice detector
(Optional Mod No. 3168)
The ice detector consists of an ultrasonic axially
vibrating tube as sensing element. The logic is con-
trolled by a micro
− processor built into the ice detec-
tor housing. Upon sensing ice as evident by a
change in frequency, at a preset level, the micro
−
processor will activate the L and R ENG ANTI − ICE
blue status lights which will start flashing and the
ICE COND indication light will illuminate in white.
When switching ENG A/I ON the blue light will
change to steady.