Avionics News March 2016 - 56

AN AIRCRAFT IS AN AIRCRAFT, RIGHT?
Continued from page 55

issuing the airworthiness certificate.
It lists limitations and information
required for type certification,
including airspeed limits,
weight limits, thrust limitations,
approved documentation, et cetera.
Manufacturers' wiring diagram
manuals are often listed in the TCDS
as "approved" or "acceptable" and
can be a great source for determining
previously used equipment such as
wire type, electric connectors and
terminal strips. There may even be
guidance in a "standard practices"
document that will provide additional

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march

2016

direction covering installations.
Fortunately for manufacturers of
equipment subject to the approval
of airworthiness, authorities' global
standards are similar. The FAA
utilizes Part 25 for fixed-wing
aircraft categorized as "transport"
and Part 23 for most that are nontransport. Across the Atlantic, the
European Aviation Safety Agency
utilizes comparable content in
Joint Aviation Requirement 23
and 25. Unfortunately, comparable
is not always sufficient to
ensure acceptance across global
airworthiness agencies, and
importing or exporting equipment
across geopolitical boundaries will

not ensure complete governing
agency acceptance without wellkept records, diligent research
and possible alteration(s) or
amendments.
Understanding Part 23 aircraft
are not always handled the same
as those approved per Part 25 is
essential to organizations supporting
general aviation. For instance, care
and maintenance of aircraft wiring,
for many years, had been "install
it and leave it." The only time
wiring was addressed was when
problems were uncovered while
performing other maintenance or a
hard electrical fault was suspected.
A number of cases have been
uncovered where metal shavings
have migrated into wire bundles,
and throughout years of vibration
and flexing, the foreign material
breached the wire insulation
resulting in electrical arcing, which
can be consequential in certain
environments such as fuel cells.
As a result of several newsworthy
aircraft accidents, including
Swissair Flight 111, the FAA
released a series of regulations
concerning electrical wiring
interconnection systems in
November 2007. EWIS is now part
of Part 25 and begins with Part
25.1701. The FAA has done a stellar
job in creating online information
to explain EWIS, and one such
job aid can be found at www.faa.
gov/training_testing/training/air_
training_program/job_aids/media/
ewis_job-aid_2.0_printable.pdf.
In addition, just accomplishing
a search for EWIS on the FAA
website will reveal numerous other,
in some cases, equally informative
programs.
Current positive aviation industry
forecasts published by Boeing

http://www.faa.gov/training_testing/training/air_training_program/job_aids/media/ewis_job-aid_2.0_printable.pdf http://www.faa.gov/training_testing/training/air_training_program/job_aids/media/ewis_job-aid_2.0_printable.pdf http://www.faa.gov/training_testing/training/air_training_program/job_aids/media/ewis_job-aid_2.0_printable.pdf http://www.faa.gov/training_testing/training/air_training_program/job_aids/media/ewis_job-aid_2.0_printable.pdf http://www.beckerusa.com

Table of Contents for the Digital Edition of Avionics News March 2016