REGULATION — LEGALLY BINDING

§ 91.413 ATC transponder tests and inspections

14 CFR Part 91 — Subpart E—Maintenance, Preventive Maintenance, and Alterations

Official text — 14 CFR § 91.413

REGULATION — LEGALLY BINDING

(a) No persons may use an ATC transponder that is specified in 91.215(a), 121.345(c), or § 135.143(c) of this chapter unless, within the preceding 24 calendar months, the ATC transponder has been tested and inspected and found to comply with appendix F of part 43 of this chapter; and

(b) Following any installation or maintenance on an ATC transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E, of part 43 of this chapter.

(1) A certificated repair station properly equipped to perform those functions and holding—

(i) A radio rating, Class III;

(ii) A limited radio rating appropriate to the make and model transponder to be tested;

(iii) A limited rating appropriate to the test to be performed;

(2) A holder of a continuous airworthiness maintenance program as provided in part 121 or § 135.411(a)(2) of this chapter; or

(3) The manufacturer of the aircraft on which the transponder to be tested is installed, if the transponder was installed by that manufacturer.

Reproduced from the eCFR. Text as amended through 2026-07-31. Verify against the official source before relying on it operationally.

SkeyeMentor explanation

Educational — not an FAA source

In plain English

The test and inspection required for an ATC transponder before it may be used, and who may perform the work.

Why it matters

Unlike the altimeter and static system check, this one applies whenever the transponder is used, not only under IFR.

Quick example

Check the aircraft maintenance records and find the last transponder test date.

Written and reviewed by the SkeyeMentor editorial team. This explanation is a study aid, not legal advice, and it is not part of the official text above. Verify current requirements through the official source before relying on them operationally.

Is this a regulation?

Yes — this is regulatory text and is legally binding.

Text published in the Code of Federal Regulations. Regulations are legally binding on pilots and operators.

Yes — this is the text of a Federal Aviation Regulation. It is legally binding. The explanation below it is SkeyeMentor educational content, not part of the regulation.