DOC AIRBUS | AMM A320FNO. 4 BEARING INDICATING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The purpose of the No.4 bearing indicating system is to monitor the correct operation of the No.4 bearing 2-position scavenge valve and to detect a No.4 bearing carbon-seal failure.
** ON A/C NOT FOR ALL The purpose of the No.4 bearing indicating system is to monitor the correct operation of the No.4 bearing 2-position scavenge valve and to detect a No.4 bearing carbon-seal failure.
No.4 Bearing Pressure TransducerA. No.4 Bearing Pressure Transducer
The No.4 bearing pressure transducer is installed on the right side of the deoiler and senses pressure at the No.4 bearing outlet line.
Accuracy : plus or minus 2.5 percent above 100 PSID, plus or minus
1 percent below 100 PSID
Linear output 1VDC to 9 VDC (0 To 300 PSIG),
Impedance 33k ohms to 100k ohms.
The No.4 bearing pressure transducer is installed on the right side of the deoiler and senses pressure at the No.4 bearing outlet line.
Accuracy : plus or minus 2.5 percent above 100 PSID, plus or minus
1 percent below 100 PSID
Linear output 1VDC to 9 VDC (0 To 300 PSIG),
Impedance 33k ohms to 100k ohms.
B. No.4 Bearing Scavenge Valve Position Indicator.
The position indicator is integral with the No.4 bearing scavenge valve which is located in the No.4 bearing compartment scavenge line.
At engine low power, the valve is open and the switch closes providing a ground signal. At engine high power, the valve closes and the switch opens.
The position indicator is integral with the No.4 bearing scavenge valve which is located in the No.4 bearing compartment scavenge line.
At engine low power, the valve is open and the switch closes providing a ground signal. At engine high power, the valve closes and the switch opens.
3. No.4 Bearing Indication
The EIU incorporates three logics allowing the monitoring of the scavenge valve operation as well as a No.4 bearing carbon-seal failure:
The EIU incorporates three logics allowing the monitoring of the scavenge valve operation as well as a No.4 bearing carbon-seal failure:
- When a No.4 bearing scavenge valve failure (stuck close or stuck open) occurs:
. an ECAM warning is displayed.
. an amber indication appears showing the position of the failed valve.
* The EIU elaborates a label used to set a message on the CFDS. - When a No.4 bearing carbon-seal failure or a scavenge valve restrictor clogging occurs:
* A message appears on the maintenance part of the ECAM status page (activated at landing).
* The EIU elaborates a label used to set a message on the CFDS.