An Argentine boat was lost a few years back, too. I don’t recall the cause of that one.
What could cause a sub to be lost during a torpedo drill, I wonder?
As I said, about a million things can cause a sub to sink at depth. Also, the casualty might not have even been part of the torp drill.maybe a high pressure pipe broke in the engine room, or maybe there was a problem and their batteries exploded and breached the pressure hull. A lot of different things could have happened. Submarining is a very dangerous business especially when serving in a third world navy; they’re not known for good maintenance or training.