If exposed power cables are unavoidably left
complete and fully operational system with the
loose, use some means to avoid their shorting out.
components grouped closely together. This lets
You can do this by covering them with a
the troubleshooter remove any unit and replace
temporary insulating shield. Place a warning sign
it with the one for testing. Bench-testing
on the main power switch in the cockpit and on
components is used when the trouble is hard to
the external power receptacle. Another very good
determine. It might be used when the unit is
precautionary measure, where applicable, is to
functioning, but does not measure up to minimum
disconnect the aircraft battery. In this case, place
standards. Bench tests are highly specialized test
a sign in the cockpit stating the battery is
installations, and only specific tests can be
disconnected. Complete all of the safety measures
run on specific components. Normally, AEs
mentioned here before starting work.
troubleshoot using a meter and a schematic.
The nature of the job determines the pro-
cedures you will use to actually do the work. You
Nonelectric Components
will either repair or replace the component or
system. Total job quality depends on the quality
So far, you have learned about fault detection
in systems using electric power. However, a
of work on smaller components/systems, such as
soldering, replacing connecting devices, safety
group of systems and components do not use
wiring, and using tools.
electricity. This group includes such items
Learn and practice good techniques. Working
as mechanical instruments, direct reading
under the supervision of an experienced AE is one
gauges, and mechanisms closely associated with
way to learn them. Another place to look for
electrical equipment. Such mechanisms are switch
actuators, mounting assemblies, mechanical
approved methods is in Installation Practices
Aircraft Electric and Electronic Wiring, NAVAIR
linkages, and any type of hardware that is part
01-1A-505. It contains the accepted way of
of an electrical system. You can not check this
performing many practical operations, and it is
equipment with a volt-ohmmeter, but the three
well illustrated.
basic rules for troubleshooting remain the same--
Often, parts replacement is the best way to
analyze, detect, and correct.
correct a malfunction. However, never use parts
replacement as a method of troubleshooting. Each
CORRECT AND TEST
year, thousands of dollars worth of instruments
and black boxes are returned to overhaul activities
Many faults may occur, and for each fault you
with labels stating that they are faulty. Upon
must perform a corrective action. There are rules
completion of test and check by the overhaul
that apply to practically all corrective actions. In
activity, many have no defect. This practice is
some cases, the detection of a fault involves more
wasteful and very expensive. The replacement of
time and labor than correcting it.
an entire unit when only a small part is at fault
Study the job and think through each step.
reflects poor maintenance practices. A typical
Form a plan of attack, and decide which tools
example of such a case is the replacement of an
you need. In addition to hand tools, consider
entire compass amplifier when there is only a
equipment, such as extension lights and cooling
faulty fuse. When troubleshooting, remember you
blowers. Refer to the MIM. It lists special tools
are working with equipment that is both expensive
you need and also describes how to gain access
and scarce. Make decisions to replace equipment
to a system component or area. Ask someone who
only after thoroughly testing it and making sure
has performed that particular job before; he/she
it is faulty.
can usually offer some very good pointers.
For the procedures to follow when replacing
As a troubleshooter, you should plan how to
and testing equipment, refer to the removal,
deal with special safety considerations you might
installation, and testing section of the MIM. Some
meet during a job. Some of these are hydraulic
of the topics covered in the MIMs are discussed
oil drainage from disconnected lines, dangling and
in the following paragraphs.
unprotected power cables, high-pressure air lines,
and the handling of heavy components. Drain or
Removal. Remove equipment in such a way
bleed off gas or liquid lines, and handle heavy
that you don't damage it more and you don't
objects with special care.
damage nearby structures. Pay attention so you
don't loose or misplace small parts. They maybe
NOTE: Only Aviation Structural Mechanics
easy to replace with new ones, but small items lost
(AMEs) work on oxygen lines.
