On June 2, the Civil Aviation Safety Information System of China released an investigation report on the air bursting and shedding of the windshield of the 3U8633 Chongqing-Lhasa flight carried out by Sichuan Airlines A319-100/B-6419 on May 14, 2018.
The investigation report shows that the biggest possible cause of this incident is that the right windshield seal of Unit B-6419 (weather seal or silicone seal) may be damaged, there is a cavity inside the windshield, and the external water vapor has penetrated and remained at the bottom edge of the windshield. After long-term immersion of the power cord, the insulation decreases, and a continuous arc discharge in a humid environment appears at the lower left corner of the windshield. The local high temperature generated by the arc causes the double-layer structure glass to break. The windshield cannot withstand the pressure difference between the inside and outside of the cockpit and burst off from the fuselage.