HYDRAULIC INDICATING SYSTEM -TEMPERATURE INDICATING

EFFECTIVITY BEJ ALL PRE SB 777-29-0024  29-30-00 
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HYDRAULIC INDICATING SYSTEM -TEMPERATURE INDICATING

EFFECTIVITY BEJ ALL POST SB 777-29-0024  29-30-00 
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777 AIRCRAFT MAINTENANCE MANUAL

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29-30-00

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HYDRAULIC INDICATING SYSTEM -FLUID QUANTITY INDICATING

General

A quantity transmitter in each of the hydraulic reservoirs measures fluid quantity. Reservoir quantity data goes to the HYDIM cards.
Functional Description

The reservoir quantity transmitters are capacitance-type transmitters. They send a signal to the HYDIM cards in proportion to reservoir fluid quantity. The HYDIM cards send reservoir quantity signals to the AIMS and to the reservoir quantity gage in the hydraulic service bay.
The reservoir quantity indication makes allowance for temperature changes to prevent nuisance refill and overfill indications.
Indication
Reservoir quantities show on these MFD formats:
*
Status display

*
Hydraulic synoptic display

*
Maintenance page.

Quantity indication shows as a decimal number. The reservoir full level shows as 1.00.
If the reservoir quantity is 1.20 or more, an OF (overfill) shows next to the quantity indication on the status display, the hydraulic synoptic display and the hydraulic maintenance page. The OF shows only when the airplane is on the ground.
If reservoir quantity is 0.75 or less, an RF (refill) shows next to the quantity indication on the status display, the hydraulic synoptic display, and the hydraulic maintenance page. The RF shows only when the airplane is on the ground.
If reservoir quantity is 0.40 or less, a LO shows next to the quantity indication on the status display, the hydraulic synoptic display, and the hydraulic maintenance page.
These advisory messages show if reservoir quantity is 0.40 or less:
*
HYD QTY LOW L

*
HYD QTY LOW C

*
HYD QTY LOW R.

The advisory messages and the LO indication reset when the quantity is more than 0.42.
Training Information Point
If the reservoir fluid level is at the top of the standpipe, the quantity indication shows 0.00.

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HYDRAULIC INDICATING SYSTEM -FLUID QUANTITY INDICATING

EFFECTIVITY BEJ ALL  29-30-00 
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