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This question is concerning the possibility of operating an Unmanned Aerial Vehicle (UAV) outdoors—a commercially available quadcopter, for example—but with the distinction of operating the UAV while tethered.

In this letter of legal interpretation, the FAA states, that:

The FAA has repeatedly affirmed it's position that any vehicle designed for tethered operations only, and not for "free flight", should be considered a kite.

An applicable kite (over 5 lbs., etc) would be subject to 14 CFR 101.

However, any UAVs which were originally designed for free flight would clearly not meet the "kite" definition—even if operated tethered, since the original design was for "free flight" and not tethered operations only.

This is my primary question: If an UAV were attached to a tether and so operated, would that UAV remain subject to all legal requirements regarding the operation of UAVs?

Additionally, I would be interested in the following:

Is there a letter of legal interpretation from the FAA on this matter, or any other regulatory or guidance material that I am not aware of?

Are there any rules governing tethered aircraft flight, in general, apart from 14 CFR 101?

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  • $\begingroup$ Not really definitive at all, but I have read articles about tethered flying cars which were allowed to be tested in tethered flight only because the tether allowed them to bypass certification rules needed for free flight. They too were obviously designed for free flight. (Of course, this could also have something to do with insurance rather than just FAA rules, who knows??) $\endgroup$ – Lnafziger May 10 '16 at 14:28
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    $\begingroup$ If you altered the UAV in such a way as to make it permanently "designed for tethered operations only" then I'd think yes, but if there is anything we know as pilots it's that the U.S. aviation laws love to be overly open to interpretation. $\endgroup$ – Ryan Mortensen May 10 '16 at 15:24
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    $\begingroup$ @Lnafziger Pure speculation but I suspect there's a big difference between "There's only one of these things and, hey, we'd really like it to fly free but we decided to tether it for testing" and "Anybody can buy one of these from the store and fly it free but I've decided to tether mine." $\endgroup$ – David Richerby May 10 '16 at 15:41
  • $\begingroup$ @DavidRicherby Maybe! But then again, once it is tethered a whole host of safety concerns go away, so maybe not! $\endgroup$ – Lnafziger May 10 '16 at 16:08
  • $\begingroup$ You said tethered UAV and I immediately thought, "are we asking about kite flying?" Guess not... ;) $\endgroup$ – Jay Carr Aug 10 '16 at 14:31
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The FAA's rulemaking document for UAVs says that tethered UAVs are not considered balloons or kites (thanks to Steve V. for finding it):

[...] a small unmanned aircraft that uses powered systems for actions such as propulsion or steering is not a balloon or kite subject to part 101

And:

[...] the FAA notes that the definition of small UAS in this rule includes tethered powered small UAS

So a UAV is not a kite and it is subject to all the general UAV regulations (I think they'll be published as 14 CFR 107 at some point). There are also a couple of FAA sources that say that if a tethered aircraft of any type is capable of free flight then all the usual regulations apply. This is from the interpretation you quoted:

Since 1957, the FAA has repeatedly affirmed its position that any vehicle designed for tethered operations only, and not for "free flight" should be considered a kite.In contrast, if an ultralight vehicle is designed to be tethered only until it achieves a predetermined altitude and is released for free flight, that ultralight is an aircraft regulated under part 103 during the entire operation.

There's also a very clear statement on tethered balloons:

Free and Tethered Flight Considerations. If a balloon is considered an aircraft under one circumstance (such as free flight), it must still be considered an aircraft under other operating circumstances, including tethered flight. Tethered balloons are considered aircraft, and must be operated in compliance with all construction, certification, airworthiness, registration, and operating regulations applicable to aircraft.

That comment about "operating circumstances" seems to be the general FAA position on tethered aircraft.

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    $\begingroup$ See also the Final Rule for part 107 (Page 80): Based on these definitions, a small unmanned aircraft that uses powered systems for actions such as propulsion or steering is not a balloon or kite... and the FAA notes that the definition of small UAS in this rule includes tethered powered small UAS (page 94) $\endgroup$ – Steve V. Aug 10 '16 at 0:11
  • $\begingroup$ @SteveV. Nice find, thanks! I've updated my answer based on that information $\endgroup$ – Pondlife Aug 10 '16 at 12:43
  • $\begingroup$ Somewhere I have a LOI on tethered operation of a helicopter... $\endgroup$ – mongo May 22 '17 at 17:07
  • $\begingroup$ After consideration, I thought I would add that one may wish to request a LOI (letter of interpretation) regarding tethered flight. If you can bound your problem (where, purpose, etc.) you might get a favorable interpretation. $\endgroup$ – mongo May 18 '18 at 13:14

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