The Problem • The F-22 Raptor computer software failed when the aircraft crossed the International Date Line. IDL
What went wrong? • The Flight Management Software failed to properly process the location data as the F-22 flew from Hickam AFB (157° W) and crossed over the International Date Line (both 180° W and 180° E).
International Date Line 1956 2007 1985 1884 1522 1937
Inadequate requirements? • The system shall calculate the aircraft’s present position latitude and longitude in degrees, minutes, and seconds. • The system shall display the aircraft’s present position latitude and longitude in degrees, minutes, and seconds.
Poorly developed code? • Rapidly changing technology from analogue to digital flight controls • Led to increasing software development • Software • Ada was mandated by government • Difficult to find/hire Ada developers