Incident Overview
Shortly after takeoff, at approximately 800 feet above ground level, the main passenger cabin door opened. The flight crew returned the aircraft to the departure airport. During the final approach, the door separated from the aircraft.
Door Status and Design
All indications are that the door was closed and locked prior to takeoff. However, the lack of damage to the door suggests it was unlocked or unlatched when it opened. The aircraft had a newly designed handrail and door handle installed, which reversed the direction of motion required to lock and unlock the door. Fourteen aircraft in the fleet incorporated this design change.
Flight Attendant Information
The number one flight attendant, who had been recently hired, had operated this handle on 16 of her 60 flights since starting. She had been on duty for approximately 14.5 hours on the day of the incident and had only about 5 hours of sleep the previous night due to her flight schedule. She reported hearing a very loud humming noise coming from the door prior to its opening.