TM 1–1520–238–T–1
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Change 5
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FAULT DETECTION AND LOCATION SYSTEM
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(FD/LS) – GENERAL
Section I.
GENERAL INFORMATION
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FAULT DETECTION AND LOCATION SYSTEM
(FD/LS) – GENERAL.
FD/LS is a method of automatically performing a built-in-test of
various systems/line replaceable units (LRUs). Flight crew and
maintenance personnel are provided with continuous
monitoring of flight critical and mission essential systems, and
keyboard initiated system testing. Faults are isolated to the
malfunctioning system and LRUs. Various aircraft controls,
displays, and indicators interface with FD/LS providing
caution/warning advisory information and the media for
operator interaction. FD/LS is a software module which resides
within the fire control computer (FCC). The FCC is considered
the primary bus controller and must be on-line to execute
FD/LS functions. The back-up bus controller (BBC) contains a
limited version of system fault detection.
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MAJOR FUNCTIONS.
a. Provides caution/advisory displays, warning displays,
and audible tones while monitoring flight critical and mission
essential equipment performance.
b. Detects failed systems during flight and ground
operations.
c. Isolates down to the aviation unit maintenance (AVUM)
replaceable LRU.
d. Displays operational status (GO/NO-GO) of the systems
that interface with the multiplex (MUX) bus.
