Security forces in Guatemala detected a plane entering airspace on 4 Nov 2021. They followed through and found it abandoned, with evidence that it transported illegal drugs. After an assessment by military technicians, Guatemalan government authorities ordered the burning of the aircraft one day later because it was not deemed safe to fly (unclear if it was because of the terrain or other). Not mentioning this controversial way of disposing of such major evidence so soon, my question is, what is the proper protocol in the US regarding abandoned aircraft of recent model that are not deemed safe to fly? Are there FAA regulations about the matter? What US authorities would do in such scenario as the one in Guatemala? My question specifically pertains to aircraft.
Short Answer: If the case is closed and the plane is neither airworthy nor evidence used in a case where the death penalty was issued, the US government has a full process for destroying it (outlined here).
If the log books were found with the aircraft it may be recovered, depending on the state in which they find the aircraft. In the US, property seized by the government in drug related cases can, in some instances, be auctioned off. The issue with aircraft is that in order for them to be deemed "airworthy" (what I assume you mean when you say "safe to fly") you would need the log books to prove that the aircraft is compliant with all relevant maintenance history and AD's.
Often maintenance logs are not stored in the aircraft as they can get lengthy and heavy over time and there is no requirement to have them onboard. So if the government seizes an aircraft that say, flew into the country illegally, there are likely no logs with it. Factory overhauls of engines can reset this (for engine logs) but that can be costly. Reconstructing airframe logs can be quite a difficult (if not impossible) task. So again, with out the logs the airframe is likely prohibitively expensive to bring the airframe back to airworthy condition but it may be liquidated nonetheless for far less than an airworthy example. Similarly with out the logs you cant even part the plane out since you cant add valid parts tags to the parts without knowing the service history. Interior trim and other non airworthy related parts can be pulled and sold without the tags but thats not really where the value is.
Interestingly in this case the aircraft was seized before being delivered to El Chapo and according to the article will be auctioned off so they presumably seized it with the Log Books.