This Fuel Quantity Indicator/Totalizer operates in any of the individual fuel quantity indicator (FQI) positions or the totalizer position. Pin jumpers in the mating connector direct operating mode, English (LB) or metric (KG) units of measure, and scaling. If an invalid configuration exists, the indicator will display “ConF” on the digital display.

In the FQI mode, the indicator shows fuel weight on a five-digit digital display and the tank percent full on a segmented arc. If the FQI establishes that there may be a small error in the displayed fuel weight, or that an accurate fuel quantitycannot be determined (blank fuel weight display), the display will read “MAINT”.

As a totalizer, the indicator shows the arithmetic sum of the contributing indicators. Data transmission between the masters and the totalizer is on dedicated digital busses, resulting in exact display correlation. Units of mea-sure (KG or LB) for the totalizer are defined by a pin jumper in the mating connector. Should there be a units mismatch between that selected for the totalizer and the units data from any of the individual master indicators, fuel quantity will be blanked and “MAINT” and both “LB” and “KG” will be displayed.

The indicator display is an integrally lit, high contrast, liquid crystal display (LCD) showing white characters on a black background. The indicator is equipped with low level, flightdeck compatible night lighting and supplemental “high intensity” white daytime lighting.

The latter provides improved LCD readability when operating in high ambient lighting conditions. The high intensity lighting comes on automaticallywhen night lighting is adjusted to zero.

The indicator performs a continuous Built-in Test (BIT) to ensure operational integrity and facilitate troubleshooting. BIT codes represent specific failures within a gauging channel. The fuel quantity display is blanked and communications to the totalizer indicator are stopped if computed fuel quantity cannot be determined. The “Fuel Qty Test” pushbutton prompts a system component display test and facilitates access to the fuel quantity indicators BIT fault history.

A one time calibration of the indicator at installation allows for zeroing the tank probe array. A multi-turn potentiometer on the rear of the unit provides access to the calibration mode.

IS&S is a global supplier of avionics displays, instrumentation, and air data products and services for a wide range of aircraft used in military, commercial, and business aviation for OEM and aftermarket applications.


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