On March 16, 2021, about 1319 Pacific Standard Time, American Airlines flight 3222, operated by SkyWest, a CRJ-700, N706SK, experienced an incident when a flight attendant fell out of the airplane while opening the main cabin door after arriving at the gate at Los Angeles International Airport (KLAX), Los Angeles, California. Of the 66 passengers and crew onboard, one flight attendant sustained serious injuries. The airplane was not damaged. The regularly scheduled domestic passenger flight was operating under the provisions of 14 Code of Federal Regulations Part 121 from Salt Lake City International Airport (KSLC), Salt Lake City, Utah to KLAX. According to witnesses, upon arrival at the gate in KLAX, the flight attendant (FA) fell from the top of the main cabin doorsteps to the ramp surface below after opening the main cabin door (MCD). She was then observed standing up, climbing back up the stairs and then falling to the ramp a second time. Ramp employees immediately came to her aid and alerted the captain of the flight who subsequently called company operations and requested emergency medical personnel be sent. She was transported to the hospital where she was diagnosed with a broken left wrist, right clavicle, and ribs. Ramp video at KSLC showed the MCD was closed without pinning the handrails when the normal procedure was for the FA to call ground handling personnel to pin the railings before closing the door. The accident flight was the FA's first flight out of Initial Operating Experience, which was performed during a flight on an ERJ-175. Normal operating procedures for the CRJ-700 MCD require the handrails to be up and pinned prior to closing the door; however, the FA did not indicate knowledge of that procedure requirement when interviewed following the accident. The FA also indicated during the interview that prior to landing, she hit her head on an open galley compartment door and felt disoriented, dizzy, and nauseated. Subsequent to the accident, the operator issued two safety bulletins to their employees describing the lessons learned from this accident and reviewing the opening procedures for the CRJ MCD. The operator also added CRJ door operation as a top safety focus area and required a demonstration of the CRJ MCD operation to the curriculum for those FAs being instructed on ERJ-175’s.