work center register. Reference to records of previous
TESTING AND OPERATIONAL CHECKS
maintenance may show a progressive deterioration of a
Aircraft systems tests and operational checks
particular system or a previous discrepancy. This
should be performed under conditions as nearly
procedure could be helpful in pinpointing the cause of
operational as possible. Such tests or checks should be
the malfunction currently being experienced.
performed in accordance with the instructions outlined
ELECTRICAL FAILURES
in the applicable MIM. Make the operational checks in
the sequence outlined in the MIM. Any discrepancies
Since practically all systems now have some
you find when performing a step should be corrected
electrically controlled components, troubleshooting
before proceeding. The operational check and the
must also include the related electrical circuits in many
troubleshooting charts have been coordinated so that
instances. Although an AE is generally called upon to
malfunctions can be isolated in an efficient manner. If
locate and correct electrical troubles, you should be
the troubleshooting aids do not list the trouble being
able to check circuits for loose connections and even
experienced, you will have to study the system
perform continuity checks when necessary. Therefore,
schematics and perform the operational check. Use
a knowledge of electrical symbols and the ability to
logic and common sense in pinpointing the cause of the
read circuit diagrams is necessary. Figure 1-4 illustrates
malfunction. The test stand to be used in performing the
the electrical symbols commonly found in schematic
operational check must be capable of producing the
diagrams.
required flow and pressure required for proper
operation. Check all electrical switches and circuit
Loose connections are located by checking all
breakers, as well as hydraulic selector valves, for
connectors in the circuit. A connector that can be turned
proper position. Perform this check before applying
by hand is loose and should be tightened hand tight.
external electrical and hydraulic power. Perform all
A continuity check is simply a matter of
maintenance in accordance with the MIM. Observe all
determining whether or not the circuit to the selector
maintenance precautions and requirements for quality
valve, or other electrically controlled unit, is complete.
assurance verification.
Continuity checks are made with the use of a
Personnel involved in troubleshooting and
multimeter. The name multimeter comes from
performing operational checks should consult the
MULTIPLE METER, and that is exactly what a
records maintained in maintenance control and/or the
multimeter is. It is a dc ammeter, an ac ammeter, a dc
package. Figures 1-10 and 1-11 show the faces of
Figure 1-11.--A typical electronic multimeter.
Figure 1-10.--A typical multimeter.
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