Flight Operational Quality Assurance (FOQA) flight data and flapping wings results were examined by the aid of Hilbert-Huang Transform (HHT) method. The purpose of applying HHT is to find the hidden frequency-based (Intrinsic Mode Functions) IMF patterns from the origin signal. From flight data of three normal flights and one abnormal flight, a case of engine No.1 failure during cruise was extracted from a twin-engine turboprop airliner. Several important alignment results of different flight phases were found in the parameter of this flight indicates the existence of potential risk factors before the event flight. The alignment results of FOQA engine failure during operation in flight are vague, and are mainly due to the fact that engine failure usually appears to be a sudden change within milliseconds. The sampling rate of engine related parameters was 1 Hz, thus is considered as the congenital missing of data that leads to lacking of precise measures. For FOQA data alignments, the pattern finding probability is approximately 55.13%. An empirical system and procedure for pattern searching is needed to handle a population of data. The hidden patterns were found in both cases and the concept of data homology was illustrated.
Journal of Aviation Safety and Management 2(3), 310-329