Airplanes crash for one or a combination of the following reasons:
1. improper design usually involving an aircraft system or component part (product liability);
2. improper manufacture usually involving an aircraft system or component part (product liability);
3. improper maintenance usually involving aircraft maintenance or overhaul of an aircraft component or part (negligence); and
4. pilot error in the operation of the airplane or air traffic controller error in directing the aircraft (negligence).
If it’s not one of those reasons, you’re pretty much down to an act of God.