Embraer EMB145 Operation Manual page 2149

ICE DETECTION SYSTEM
Ice detectors 1 and 2 are respectively installed at the airplane's left and
right nose section, to provide icing condition detection.
The ice detector was designed to pick up ice quickly. Therefore, in the
most cases, ice will be detected before it can be noticed by the crew.
NOTE: Notwithstanding ice detector monitoring, the crew remains
responsible for monitoring icing conditions and for manual
activation of the ice protection system if icing conditions are
present and the ice detection system is not activating the ice
protection system.
A 0.5 mm (0.020 inch) ice thickness, on any probe, causes bleed air
anti-icing system automatic mode activation, a SPS angle of attack set
values reduction (refer to Stall Protection System on Section 2-4 – Crew
Awareness), and an advisory message to be presented on the EICAS.
During ice encounters, the icing signal remains active during 60
seconds. Simultaneously, an internal ice detector heater is activated to
de-ice the unit and probe. When the probe's natural frequency is
recovered, heating is de-energized. Once deiced, the sensing probe
cools within a few seconds and is ready to once more monitor ice
build-up. Then a new detection cycle begins and remains as long as
the ice condition persists.
In case of failure of any or both ice detectors, a caution message is
presented on the EICAS and the bleed air thermal anti-icing system may
be activated through the OVERRIDE knob on the Ice Detection panel.
The system's normal operation may be checked through the TEST
knob on the Ice Protection panel.
EICAS MESSAGES
TYPE
CAUTION
ADVISORY
REVISION 41
AIRPLANE
OPERATIONS
MANUAL
MESSAGE
ICE DETECTORS FAIL
ICE DET 1 (2) FAIL
ICE CONDITION
Copyright © by Embraer. Refer to cover page for details.
ICE AND RAIN
PROTECTION
MEANING
Both ice detectors have
failed.
Associated ice detector
has failed.
Airplane is flying under
icing conditions.
2-15-15
Page Code
1 01