*
No engine start of related engine
*
No fan case overheat.
or
*
Flight deck EAI selector is set to AUTO
*
Ice sensed by the ice detector(s)
*
No engine start of the related engine
*
No fan case overheat.
If the EAI selector position shows invalid on the 629 data bus, the ACIPS control card sets operation to AUTO.
The EAI system is off when the flight deck EAI selector is set to OFF.
When the EAI selector is set to AUTO or ON, the ACIPS control card controls the EAI valve to one of these levels of control:
*
Heat flow target.
*
Mass flow rate.
*
Minimum distribution pressure of 10 psig.
*
Full open.
The EAI system controls to a heat flow target for these conditions:
*
Operation inside of the icing envelope limits
*
Operation outside of the icing envelope and below the mass flow limit.
The EAI control card calculates the heat flow target as a function of altitude, ambient temperature, flight phase and mach number.
EFFECTIVITY BEJ ALL 30-21-00
Page 18
D633W101-BEJ Sep 05/2002
ENGINE ANTI-ICE -FUNCTIONAL DESCRIPTION
The EAI system controls to a mass flow rate while operation is outside of the icing envelope and the mass flow is at the high limit. The EAI control card calculates the mass flow rate as a function of altitude.
The icing envelope has these limits:
*
Altitude; -2500 feet to 37,500 feet
*
Temperature; -40F to 50F (-40C to 10C).
The EAI system keeps a minimum pressure of 10 psig in the EAI distribution duct when in operation.
The EAI valve is set to full open when any of these conditions occur:
*
Both EAI pressure sensors fail
*
The torque motor circuit is open.
The EAI pressure sensors supply feedback information to the ACIPS control card for valve control and indications. There are two pressure sensors on each engine. Only one sensor is necessary on each engine for the EAI system to operate in AUTO.
The ACIPS control card closes the EAI valve if any of these conditions occur:
*
Engine start
*
Fan case overheat
EFFECTIVITY
BEJ ALL
*
EAI selector set to OFF
*
EAI selector set to AUTO with no ice sensed.
If the DLODS system senses a fan case overheat condition, the EAI ACIPS control card latches the EAI valve in the closed position. You can reset the system when the overheat condition is no longer present. To do this you move the EAI selector to OFF and then to AUTO or ON.
See the duct leak and overheat detection system section for more information (SECTION 26-18).
BITE Operation
At power-up, the ACIPS control cards do built-in test (BIT) on internal hardware and software functions and interfaces.
The ACIPS control cards do a periodic BIT if all of these conditions are true:
*
It is more than 20 seconds and less than five minutes after landing
*
No fan case overheat is present
*
Time since the last periodic test is more than 24 hours.
You can use the maintenance access terminal (MAT) or portable maintenance access terminal (PMAT) to do these EAI ground tests:
*
Engine running
*
Engine not running.
30-21-00
Page 19 D633W101-BEJ Sep 05/2002
ENGINE ANTI-ICE -FUNCTIONAL DESCRIPTION
The BITE in the ACIPS control card can find short and open circuits in the system. The BITE does a check of these components:
*
ACIPS control cards
*
EAI valve controller
*
EAI valve
*
EAI pressure sensors
*
Ice detector.
The BITE finds a failure if either EAI valve does not:
*
Open
*
Close
*
Regulate.
Interfaces
The ACIPS control cards gets data from these systems:
*
Opposite ACIPS control card; ice sensed, failed ice detection
*
OPAS; EAI selector position, engine start selector position
*
DLODS; fancase overheat
*
FMC; engine type, flight phase
*
AIMS; engine on
*
AGS; air/ground status
*
ADIRU; mach number, static pressure, static air temperature, total air temperature
*
EEC; P3 burner pressure, T3 selected temperature.
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