Incident Description
The separation of the passenger/crew door occurred while the on-demand passenger flight was cruising at flight level 190. At that time, the aircraft was operating in visual meteorological conditions with no reported turbulence. The door detached from the airframe without any prior warning.
Door Recovery
Following the incident, the door was retrieved. It was found to be in the locked position, indicating that the locking mechanism was engaged at the time of separation.
Examination Results
A comprehensive examination of the door was carried out. The upper aft latch bolt was found to have a fatigue fracture. The door frame and the latch plates were inspected and showed no indications of damage. The investigation focused on the latch assembly, and no other anomalies were identified.