>>81498284
In the case of a parachute, the greatest danger for any skydiver when parachuting is getting entangeled into their own chute when landing, especially in water. Imagine 200 passengers trying to evacuate the plane while in water but when they exit the plane, they're all trapped under a giant ass parachute and all it's wires.

That planes doesnt have any type of floatation device that can be activated might be that planes reaches 30 000 feet where the air pressure is very low and there might be a danger that any such device would explode or detonate mid air due to the change in pressure.