The official warning of Typhoon Yancy(1990) over land was lifted by ROC Central Weather Bureau (CWB) at 0415TST(UTC+8) on 20 August 1990, and 27 hours later, the B-1905 carrier, a twin-engine Beech-1900 aircraft, prepared to descend its altitude for the landing operation. At that time, due to unknown reasons, the aircraft made a crash into a muddy sugarcane field at Dongshih, Yunlin County in central Taiwan at 0758TST(UTC+8) on 21 August 1990, killing all 18 military officers on board. The study tries to focus on the possible causes of this event through the synoptic-and meso-β scale analyses from the meteorological points of view. The preliminary results delineated that the B-1905 carrier faced severe weather situations, including the intensely vertical and horizontal wind shears, obvious updrafts/downdrafts, and the derived turbulence. Therefore, the combined impact of typhoon outer circulation and southwesterly flow, initiating a local confluent zone over the southern Taiwan Strait, was one of the probable threats for flight safety after lifting of typhoon warning. Also, a resulting schematic 3-D conceptual model for understanding the meso-β scale weather circumstances associated with the aviation threat was presented. Hopefully, the hazardous situations could be identified in advance, and might be avoided in the future.