Controlled flight into terrain used to be one of the leading causes of aviation accidents. All it took was for the pilot(s) to get disoriented, distracted, or

Controlled flight into terrain used to be one of the leading causes of aviation accidents. All it took was for the pilot(s) to get disoriented, distracted, or make a bad miscalculation, particularly at night or in cloudy weather. Ground warning sensors and training are better now so there's less of it, but you still get it from time to time.