one which we have no solid knowledge about what caused it.
Actually I think we can be pretty sure what caused it. Going into hot and high mountain airports with a fully loaded plane which is under powered is a recepie for disaster.
Someone I know checked out a couple of experienced UK airline pilots on a Archer III. Next day three turned up with their luggage to go flying and in chatting he found out that they were planning to fly to Big Bear in the mountains. 30C and 6700' elevation. No you're not he said.....