What are the requirements for radio systems in aircraft? For example, are there requirements about:

  • Reception ability
  • Transmit ability
  • Transmit power

This is primarily about voice communication systems, but information about other radio systems is welcome as well.

  • 1
    $\begingroup$ What radio systems are you referring to? Voice communication or those for navigation / surveillance / data comms as well? $\endgroup$
    – DeltaLima
    Commented Jun 30, 2014 at 21:09
  • $\begingroup$ There is a big difference in requirements between airspace classes, and between flight rules used. As emphasized by vortaq7, no radio are mandatory for VFR in E and F airspaces in the US. But as soon as IFR is used, or A, B, C or D airspaces are entered, there are requirements for radio equipments (duplex voice, navigation, ILS, transponder, TCAS, SELCAL, GNSS, ELT) $\endgroup$
    – mins
    Commented Jun 7, 2015 at 9:17

2 Answers 2


What are the requirements for radio systems in aircraft?

Generally there aren't any, at least as far as "being required to have radios".

It is perfectly legal to fly around in most of the United States in a Piper Cub with no radios of any kind.
Indeed, unless it's been retrofitted with one a Piper Cub would have no electrical system at all - so you would only be able to fly under "daytime VFR conditions" in airspace not requiring communication with air traffic control (absent special arrangements).

If you elect to fly an aircraft equipped with radios (as most of us do) there are specific requirements those radios must meet, which are described in Technical Standard Orders (TSOs).

This is not a comprehensive list, but:

  • For Communication radios these are outlined in AC 90-50D and TSO C-169a.
  • Transponders must meet specific TSO performance criteria per FAR 91.215
  • Navigation Radios (VOR/ILS/ADF) must meet specific TSO performance criteria if used under instrument flight rules.
    The TSO number for these escape me at the moment but I'm sure you can look them up.
  • GPS systems must meet TSO C145c / TSO C146c requirements (if used for IFR navigation).
  • The Emergency Locator Transmitter (ELT) must meet specific TSO criteria.

The requirements obviously vary based on the type of radio, and typically reference other industry standards (for example TSO C-169a for VHF communication radios sends you over to RTCA/DO-186B for the actual performance criteria).

  • 1
    $\begingroup$ Transport Category aircraft certificated under 14 CFR Part 25 do have requirements for radios per §25.1307 Miscellaneous equipment. (d) Two systems for two-way radio communications... and (e) Two systems for radio navigation... $\endgroup$
    – Gerry
    Commented Jul 6, 2018 at 11:47

There are differences also between if the airplane is Experimental, or Certificated. Equipment that is marketed for Experimantal aircraft may not be installed in Certified airplanes - for Certified, there are additional steps taken by the manufacturer to satisfy the FAA. This can be seen at the OEM websites, and by the resellers.

Garmin G5 for example:

Experimental price 1199 USD

Certified price 2149 USD

Transponders must be permanantly mounted and ADS-B Compliant by Jan 1, 2020 for pretty much any plane that needs to have radio communications. Originally non-electrically equipped (old tail draggers for example) are exempt, but than cannot fly into radio required regions without prior coordination.

FAR 91.225

FAR 91.227

  • 1
    $\begingroup$ Can you expand on this and add some sources? What exactly are the differences between experimental and non-experimental in this case, for example? $\endgroup$
    – Pondlife
    Commented Jul 5, 2018 at 15:35
  • $\begingroup$ I don't know, one would have to inquire with the OEM. $\endgroup$
    – CrossRoads
    Commented Jun 28, 2019 at 23:17

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