Investigation led by AIB - Sri Lanka

Incident to the Airbus A330 registered 4R-ALR operated by Srilankan Airlines on 21/03/2021 en route

Preliminary data based on the notification from the Sri Lankan authorities:

During cruise phase over Jakarta FIR at FL 390, Auto pilot 1 disengaged and encountered an altitude deviation. Flight crew manually controlled and returned to FL 390. Aircraft landed at the destination safely.