Operation Manual Part 2

Aerosoft – Digital Aviation

CRJ-70 & CRJ-900

AOM PART 2

Systems Description

VOL

5-1-77

26-Jul-2017

ICE & RAIN PROTECTION

The aircraft does not need much protecting from rain if no icing conditions persist (definition is coming up in a

second), hence windshield wipers are the only system for rain protection.

Icing conditions are defined as follows:

TAT of 10°C and less and visible moisture like fog, clouds, any form of precipitation,

except the SAT is -40°C (-40°F) or below.

Icing may affect the functionality of certain aircraft systems, alter the aerodynamic of the aircraft’s wings and if

sucked into the engine lead to engine trouble. Hence several systems need to be protected from icing:

• The wings leading edges

• Air data sensors like pitot tubes, angle of attack sensors, static ports, etc. pp)

• The engine intakes / cowls

• The cockpit windows

There are two approaches to heat the mentioned systems / areas: either by extracting bleed air from the

aircraft engines or by means of an electrical heating.

Apparently extracting bleed air from the engines reduces the available amount of thrust. Accordingly, the

engines RPM must be increased a little to compensate the extracted air for heating. Therefore, you’ll

experience an increase of N

, when activating the anti-ice systems. The more systems are supplied with bleed

air the bigger the increase of N

is going to get.

The following systems are heated with bleed air:

• Wing anti-ice

• Engine intake cowl anti-ice

Whereas the following systems are electrically:

• Windshields and side windows

• Air data probes and sensors

An ice detection system assists the crew by warning of possible ice accumulation. The ice detection system is

operational as soon as AC power is available. In case either detector senses icing conditions an amber caution

“ICE” is indicated on the EICAS if either the wing- or cowl-anti-ice system is still off. Failures of the anti-ice

systems as well as bleed air leakages are not simulated.

The following sections introduce the controls for each sub-system, the indications on the Anti-Ice EICAS

Synoptic Page as well as possible EICAS messages.