I think I can understand there might be circumstances in which a small airline would prefer to write off an aircraft and file an insurance claim. What authority exists to enforce the retrieval of the aircraft and demand an investigation?
A full public autopsy report is going to be most unlikely imo. Just looking at her and considering her age, I would expect high cholesterol, atherosclerosis, possibly diabetes...and how embarrassing that would be for the head of the Hawaii Department of Health...
The most that can be expected is an announcement of heart failure.
This is the second Cessna that has had engine failure in the past 3 months in Hawaii, when engine failure is very rare for that aircraft. Anybody concerned about safety should be pushing to have that aircraft dug up, to find out if there is a manufacturing problem that caused the engine failure. From what I’ve read, the most common reason for engine failure is ice but that’s not a problem in Hawaii so having these 2 engine failures in such close proximity raises alarms regarding the safety of the aircraft.