Ok, folks, this has taken a while but I thought I should try to post here the "Official answer" straight from the horse's mouth so to speak.
https://www.faa.gov/about/office_or...association - (2015) legal interpretation.pdf
You can click on the link above I hope or I tried to copy it below but the formatting is a little goofy.
U.S. Department
of Transportation
Federal Aviation
Administration
Richard A. Peri
AUG 2 B 2015
Aircraft Electronics Association
601 Pennsylvania Ave., NW
Suite 900, South Building
Washington, DC 20004
Re: Repair Station Maintenance on Aircraft Not Subject to Part 43
Dear Mr. Peri:
This letter responds to your April27, 2015 request for legal interpretation. In your letter,
you ask whether a properly rated repair station may perform tests and inspections on
altitude-keeping and transponder equipment for experimental aircraft (i.e., aircraft with
experimental airworthiness certificates), in light of the fact that parts 43 (maintenance,
preventive maintenance, rebuilding, and alteration) and 145 (repair stations) of Title 14 of
the Code of Federal Regulations (14 CFR) specifically do not apply to experimental aircraft.
For the reasons described below, the answer to your question is yes, FAA regulations allow
a repair station to test and inspect equipment on board an experimental aircraft.
Part 43 "prescribes rules governing the maintenance, preventive maintenance, rebuilding
and alteration" of aircraft. However, as you note in your letter,§ 43.l(a) limits the
applicability of part 43 to "[a]ircrafthaving a U.S. airworthiness certificate ... ; [f]oreignregistered
civil aircraft used in common carriage or carriage of mail under [parts 121 or
135]; and ... component parts of such aircraft." Section 43.1(b) further limits the
applicability of part 43, stating that "[t]his part does not apply to ... [ a]ny aircraft for which
the FAA has issued an experimental certificate," unless certain exceptions apply. 1 .
The exclusion of experimental aircraft from part 43 has consequences throughout our
regulations. The applicability provision ofpart 145, for example, is based on the
applicability of part 43. It states, among other things, that "[t]his part ... contains the rules
a certificated repair station must follow related to its performance of maintenance,
preventive maintenance, or alterations of an aircraft ... or component part to which part 43
applies." 14 CFR § 145.1 (emphasis added.) Therefore, as we have described in previous
legal interpretations/ just as part 43 does not apply to certain aircraft, neither does part 145.
1 The exceptions include aircraft for which FAA has previously issued a different kind of airworthiness
certificate, or any aircraft for which the FAA has issued an experimental certificate under certain special rules
for light sport aircraft. 2 Memorandum to Carol E. Giles from Rebecca MacPherson, Request for Policy Interpretation of 14 CFR
Parts 43 and 145 for FAA Certificated Repair Stations Working on Foreign-Registered Aircraft (Aug. 24,
20 10). This 20 lO interpretation discussed the applicability of pru.i 145 in the context offoreign-registered
aircraft, many of which are also excluded from part 43. In the interpretation, we stated that "the [applicability
of part 145) repair station rules [is) circumscribed by the maintenance rules in part 43, which, by its own terms,
2
Furthermore, because part 145 specifically does not apply to certain experimental aircraft,
neither does the prohibition in§ 145.201(b), that no repair station may "maintain or alter any
article for which it is not rated .... " In other words, if an experimental aircraft, or a
component of an experimental aircraft, is outside the scope of part 145, then§ 145.201(b)
does not prohibit a repair station from performing maintenance on that aircraft or
component. 3
Part 91 applies to a much broader set of owners, operators, and aircraft than parts 43 and
145. More specifically, part 91 applies to, among other things, experimental aircraft
operations. As you note in your letter, §§ 91.411 (b) & 91.413( c), respectively, set out the
requirements for testing and inspecting altitude-keeping and transponder equipment. In
general, these sections prohibit the operation of any aircraft under IFR unless the aircraft's
altitude-keeping and transponder equipment are tested and inspected at least every 24
months, and found to comply with the requirements of part 43. Therefore, even though
part 43 by its own terms does not apply to experimental aircraft,§ 91.411(a) and (b), and
§ 91.413(a) and (c), incorporate certain part 43 requirements, including those that apply to
the altitude-keeping and transponder equipment that are the subject of your inquiry.
With all of this in mind, we return to your question: whether a certificated repair station may
perform maintenance, described in part 43 and required by§§ 91.411 & 91.413, on
experimental aircraft. We have identified no FAA regulations, including§ 145.201(b), that
would prohibit a certificated repair station from performing maintenance for an owner or
operator who seeks to bring an experimental aircraft into compliance with§§ 91.411 &
91.413. Furthermore, although many experimental aircraft are categorically excluded from
parts 43 and 145, those aircraft are not excluded from§§ 91.411 & 91.413, which impose
certain part 43 requirements. Finally, §§ 91.411 & 91.413 require the equipment discussed
in this interpretation to be tested by certain specified individuals or organizations and, as you
state in your letter, in many cases a part 145 repair station is the only viable option for a the
owner or operator of a general aviation aircraft.
[are) limited to aircraft having U.S. airworthiness certificates and foreign-registered aircraft used in common
carriage (or the carriage of mail) ... by United States air carriers." 3 This interpretation assumes that there is no dispute regarding whether the equipment in question will be used
on an experimental aircraft. We do not address a situation in which an operator represents that an article is part
of an experimental aircraft, but the repair station has reason to believe the article will be used on an aircraft
subject to part 43.
3
This response was prepared by Benjamin Jacobs, an attorney in the Regulations Division of
the Office of the Chief Counsel, and was coordinated with the Aircraft Maintenance
Division (AFS-300) of the Flight Standards Service. If you need further assistance, please
contact our office at
(202) 267-3073.
Sincerely,
d~~ Lorelei Peter
Acting Assistant Chief Counsel for Regulations
