A technique for recovering nonsynchronized data from a digital flight data recorder

How critical data in out-of-synch areas of a digital flight data recorder tape can be recovered using a serial binary technique called BITDUMP is explained. Digital flight data recorder data recovery depends on the acquisition of a synchronization word once every second. Critical synchronization timing is interrupted if tape motion becomes unsteady or if the tape breaks on impact in an aircraft accident. Several cases where synchronization of critical data was lost because of tape breakage, as in the American Airlines DC-10 accident at Chicago, Illinois, on May 25, 1979 and the Air New Zealand DC-10 accident in Antarctica on 28 November 1979 are cited. The American Airlines DC-10 accident is analyzed in detail to demonstrate BITDUMP application.