Embraer ERJ175 N637CZ accident near Cut Bank, Montana

Probable cause

an unexpected encounter with clear air turbulence.

NTSB analysis

On June 16, 2018, about 2200 MDT, Compass Airlines flight 5774, N637CZ, Embraer 175, encountered turbulence while in cruise flight at flight level 300 while enroute to Calgary International Airport (CYYZ), Calgary, Alberta, Canada. Of the 73 passengers and crew onboard, one flight attendant was seriously injured. The flight was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from Salt Lake City International Airport (KSLC), Salt Lake City, Utah to CYYZ.

According to the flight crew, air traffic control (ATC) relayed pilot reports of a "smooth ride with light chop" for their route of flight. The airplane was in visual meteorological conditions and the seatbelt sign was illuminated. At the time of the turbulence encounter the aft flight attendant was finishing up beverage service and was thrown against the bulkhead and jumpseat. The flight attendant was unable to complete her duties due to the injury and two passengers assisted the flight attendant until landing. Upon arrival at the gate in CYYZ, the flight attendant was transported to the hospital where she was diagnosed with a broken vertebra.

Text from the NTSB. Open the NTSB docket for DCA18CA255 for the full record.