Boeing 737-832 N374DA accident near Detroit, Michigan

Probable cause

An in-flight encounter with forecasted turbulence, which resulted in a serious injury to a flight attendant. Contributing to the accident was the flight attendant not being seated with her seatbelt fastened when the encounter occurred.

NTSB analysis

The flight crew received a preflight weather report as well as updated weather information while en route that advised them of expected turbulence near their destination airport. The National Weather Service issued multiple in-flight weather advisories current for the destination area including a significant meteorological advisory for occasional severe turbulence between 22,000 and 30,000 feet. As a result, the flight crew advised the cabin crew that service would have to be completed prior to entering the area of expected turbulence. As the flight approached its destination, the flight crew made an announcement for passengers and cabin crew to remain seated and make sure their seatbelts were fastened. The flight encountered severe turbulence while descending through 29,000 feet mean sea level, and one flight attendant, who did not have her seatbelt fastened, received serious injuries, and two flight attendants and one passenger, who also did not have their seatbelts fastened, received minor injuries. According to the flight data recorder data (FDR), during the event, the maximum vertical acceleration was + 1.568 Gs and the minimum was -0.30 Gs over a time period of 0.625 seconds; these vertical accelerations are considered severe, per International Civil Aviation Organization standards. The accident site was located within the area of moderate to severe turbulence potential.

Text from the NTSB. Open the NTSB docket for CEN12LA166 for the full record.