Incident Overview
On December 17, 2017, at approximately 2345 central standard time, SkyWest flight 5788, an Embraer ERJ700 (registration N128SY), experienced a sudden pitch correction while descending into St. Louis International Airport (STL), St. Louis, Missouri. The aircraft was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled domestic passenger flight from San Francisco International Airport (SFO) to STL. No damage to the airplane occurred, but of the 57 passengers and crew onboard, one flight attendant sustained a serious injury.
Flight Crew Actions
The flight crew consisted of a captain, serving as pilot monitoring, and a first officer (FO), serving as pilot flying. The FO was on his second day of initial operating experience (IOE). The air was smooth with no turbulence. Air traffic control requested the flight to maintain its best forward speed and cleared the flight direct to the airport. The crew discussed and planned the descent, but after entering the data into the flight management system (FMS), they realized they were past the top of descent point for the planned 3-degree descent path. Consequently, the captain directed the FO to select flight level change, causing the descent rate to briefly exceed 5,000 feet per minute and the airspeed to increase. To prevent an overspeed condition, the captain instructed the FO to deploy the speed brakes; however, the speed continued to increase. The captain then disconnected the autopilot and pitched the nose up.
Injuries and Aftermath
During the unexpected pitch input, the rear flight attendant was preparing the galley for landing. She was thrown off-balance and fell onto the floor, twisting her ankle. Medically qualified passengers aboard provided assistance until landing. After the aircraft landed, the flight attendant was transported to a hospital, where she was diagnosed with a fractured ankle.