improper training to poor application of procedures, fatigue
Fatigue = pilot problem .. not aircraft problem
Poor application of procedures = pilot problem .. not aircraft problem
Improper training = pilot problem (pilots are trained by pilots) .. not aircraft problem
Exactly what I said ... the pilot(s)
Or if you want ...
Fatigue .. you don't drive a car with fatigue as you will fell asleep and have accident
Procedures ...You must respect the traffic laws or you will have accident
Training .. You must go to driving school and have a driving license .. or you will have problems
So ... the driver is the problem .. not the car ...