上降元大1.4 Military Aviation Problems SHANGHAI JIAO TONG UNIVERSITY An F-18 crashed because of a missing exception condition: if ..then ..without the else clause that was thought could not possibly arise. In simulation,an F-16 program bug caused the virtual plane to flip over whenever it crossed the equator,as a result of a missing minus sign to indicate south latitude. Software EngineeringSoftware Engineering 1.4 Military Aviation Problems An F-18 crashed because of a missing exception condition: if ... then ... without the else clause that was thought could not possibly arise. In simulation, an F-16 program bug caused the virtual plane to flip over whenever it crossed the equator, as a result of a missing minus sign to indicate south latitude