Airline plane crashes can be defined as ﾑan aircraft-related occurrence in which a person is either injured or killed, an aircraft sustains structural failure or damage, or the aircraft goes missing or becomes inaccessible'. Aircraft crashes are an infrequent but ever-present danger within air travel, with reports of crashes dating back to before the first successful powered flight by the Wright brothers in 1903. Human error and mechanical failure are the most common reasons for plane crashes, with many human errors resulting from adverse weather conditions. Hijack/sabotage and military action are other reasons. Crashes that result in human death are known as fatal plane crashes.