A Shenzhen Airlines Airbus A330-300, registration B-302E performing flight ZH-9209 from Shenzhen to Xian (China), was climbing through 9100 meters (FL300) out of Shenzhen when the crew initiated an emergency descent to 3600 meters (FL118) due to the loss of cabin pressure. The aircraft levelled off at 3600 meters about 5 minutes after leaving 9100 meters. The aircraft subsequently attempted to climb again, however, aborted the climb at 6000 meters (FL197), turned around to return to Shenzhen and landed safely back in Shenzhen about 100 minutes after departure.
A replacement Airbus A330-300 registration B-1036 reached Xian with a delay of about 4.5 hours.
On Aug 13th 2020 China's Civil Aviation Authority reported the seal of the aft cargo door was faulty causing the loss of cabin pressure.
The occurrence aircraft remained on the ground for about 70 hours before returning to service.