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?