It is normal to pose questions about an accident. The welfare of the crew and don't forget the passengers and those lost on the ground goes without saying. Everyone wishes them well.
I've flown the Convair 340 and there is no provision in the AFM for a flight engineer. The 'jump' seat is an observation seat. Fortunately the GoPro camera set-up will give investigators a full portrait of the cockpit and it had sound as well.
It's a sad event however like all aviation accidents the truth is incontrovertible and must be revealed.