Avionics News May 2015 - 14

F R O M
R I C
P E R I
A EA V I C E P R ES I D E N T O F G OV E R N M E N T & I N D U ST RY A F FA I RS

The Aircraft Electronics Association's international membership continues to grow. Currently, the AEA represents avionics
businesses in more than 40 countries throughout the world. To better serve the needs of the AEA's international membership,
the "International News and Regulatory Updates" section of Avionics News offers a greater focus on international regulatory
activity, international industry news and an international "Frequently Asked Questions" column to help promote standardization.
If you have comments about this section, send emails to avionicsnews@aea.net.

FREQUENTLY
ASKED QUESTIONS
United States
Part 135 Transponders
The following information is from the Federal
Aviation Regulations.

QUESTION:

An active question during this year's AEA International
Convention & Trade Show follows: What was and was
not considered an alteration regarding transponders on
Part 135 aircraft?

ANSWER:

Let me bind this answer to section 135.143(c), the
rule that requires all "new" transponder installations to
meet TSO-C112 (Mode S).
While normal maintenance actions might require
the removal of a defective unit and replacement with
an identical unit (of a different serial number) without
triggering a requirement for upgrades or alterations,
this rule is uniquely different. In this case, the need to
replace a defective transponder with another serial numbered transponder (same make/model but different serial
number) actually triggers this rule and is considered an
"installation."

avionics news

may

2015

Paragraph 135.143(c) (2) is quite clear that as long as
the installed equipment is serviceable, normal removal,
repair and reinstallation maintenance actions are not
considered as an "installation." However, removal of
a defective transponder and replacement with a serviceable (different serial numbered) transponder is.
Paragraph 135.143(c) (2) (iii) does allow fleet operators
the use of rotables; however, this paragraph clearly limits this process specifically to fleet operations.
For purposes of paragraph (c)(2) of this section, "installation" does not include (i) Temporary installation of TSO-C74b or
TSO-C74c substitute equipment, as appropriate, during maintenance of the permanent
equipment.
(ii) Reinstallation of equipment after temporary removal for maintenance.
(iii) For fleet operations, installation of
equipment in a fleet aircraft after removal of
the equipment for maintenance from another
aircraft in the same operator's fleet.
Note: The AEA offers "Frequently Asked Questions" to foster
greater understanding of the aviation regulations and the rules
governing the industry. The AEA strives to ensure FAQs are as
accurate as possible at the time of publication; however, rules
change. Therefore information received from an AEA FAQ should
be verified before being relied upon. This information is not meant
to serve as legal advice. If you have particular legal questions, they
should be directed to an attorney. The AEA disclaims any warranty
for the accuracy of the information provided.

Avionics News May 2015

Table of Contents for the Digital Edition of Avionics News May 2015