Ariana Afghan Airlines Flight 202 (2005)
Due to this horrible Boeing 737 crash, engineers had to improve the way they maintain planes. This also led to an improvement in pilot training. Out of 27 people on the flight, 24 of them died. The main cause of this crash was pilot error and a fire in engine number one. The flight was previously delayed for 20 hours because of technical issues, but those issues were overlooked and the result was fatal (Aviation Safety).