Why dont planes have parachutes in case they go down?
Because the amount of parachutes required to slow down a plane would take as much as half their passenger capacity, and even then, it wouldn’t do anything as the weight would be almost impossible to divide so it won’t get torn to small pieces when the parachutes deploy. edit: You can’t open plane doors when it’s in flight due to cabin pressure holding them closed, and even if you did, most likely you would get hit by either the wing (front door) or the horizontal stabilizer (rear door). Most plane crashes happen so fast and from low altitudes that you wouldn’t have time to even get off your seat anyway.