I just don't see how the pilot could ever be criminally responsible.
I don't see why not: for example a pilot might knowingly fly an aircraft with a technical fault, or deliberately exceed the design limitations and, as a direct result, cause an accident resulting in death or injury. I think that would justify a charge of manslaughter.
For clarity: that comment is made as a general point only and is specifically NOT in connection with this awful accident about which I know only what I have read here.