Any incident in which an aircraft is forced to land in an uncontrolled manner after takeoff may be described as an air plane crash. Air plane crashes may be caused by technical faults with the aircraft operation systems, problems with the aircraft structure or engines, pilot error, bad weather or sabotage. Should any problem arise with an aircraft, there is a higher probability of a crash than when there is a problem with other forms of transport, as the plane cannot simply stop while the problem is fixed. Air plane crashes are relatively uncommon, but when they do occur they are likely to have serious consequences caused by high velocity impact. Air plane crashes not only injure those on board, but may also cause significant injury to people on the ground as well as massive structural damage.