On February 8, 2003, about 1704, Atlantic standard time, an Aerospatiale ATR 72-212, N448AM, registered to AMR Leasing Corporation, and operated by American Eagle Executive Airlines Inc., as flight 5131, a Title 14 CFR Part 121, scheduled international passenger flight, had a passenger that was injured while deplaning at San Juan, Puerto Rico. Visual meteorological conditions prevailed, and an instrument flight plan had been filed. The airline transport-rated pilot, first officer, two flight attendants, and 57 passengers were not injured. One passenger received serious injuries. The flight originated from Christ Church, Barbados, the same day, about 1435. According the airline's director of safety, the airplane had arrived at the terminal and was in the process of deplaning. The director of safety further stated that as the as the 53rd passenger in the sequence of 58 passengers exited the airplane, she grabbed the handrail at the top of the stairs, and the handrail collapsed. He said the passenger fell from the top of the stairs to the ground, and sustained serious injuries. Postincident examination of the hand rail and its locking mechanism did not reveal any anomalies.