Airbus A319 cockpit window blowout due to water ingress via damaged seal
The captain in the left-hand seat was Pilot Flying, the co-pilot in the right-hand seat served as the Pilot Monitoring. A second captain sat in the observer seat. After reaching cruising altitude of 9800 m (32100 feet), the second captain moved to the passenger cabin.
At 07:07:05, about 2.2NM west of MIKOS on the B213 airway, a muffled noise was heard in the cockpit and the crew found a radial mesh crack in the right
indshield, which the crew described as "very bad ... it’s all cracked." As the co-pilot grabbed his Electronic Flight Bag to check the Quick Reference Handbook (QRH), the captain requested a descent and a diversion to Chengdu as soon as possible.
After permission was obtained from air traffic control, the captain immediately executed the descent procedure. During the descent, when the co-pilot searched for the QRH related program, the right windshield fell off and the cockpit explosively depressurized.
The co-pilot was blown from his seat by the strong decompression airflow. During this motion, co-pilot's body involuntarily touched the sidestick causing a large amount of forward and right input. Thus the autopilot was disconnected and the aircraft's attitude suddenly changed. The captain immediately tranistioned to manual control of the aircraft.
The captain then experienced difficulty in retrieving his oxygen mask which was located on the left side of his seat and a bit to the rear. He used his right hand to reach across, because his left hand was used to control the sidestick. Meanwhile the aircraft was shaking violently and he was not able to get his oxygen mask. The rate of descent then increased from 3000 ft/min to a maximum of 10,279 ft/min.
The crew knew that the runway 02L ILS was unavailable at Chengdu Shuangliu Airport, so they opted for an ILS approach to runway 02R, and broadcasted their intentions during the approach. Because the aircraft landing weight exceeded the aircraft's maximum landing weight limit, the crew performed an overweight landing.
After the aircraft stopped at about 07:41 hours, the crew communicated about the personal injury of the co-pilot, and informed the tower and dispatch of the relevant situation, and to send ambulances.
The final investigation report pointed out that the most likely cause of this incident was that the seal of the right-hand windshield had been damaged, causing external water vapor to enter.
The insulator of the power supply wire was reduced after being soaked for a long time, leading to a continuous arc discharge in a humid environment. The high temperature caused by the arc further ruptured the double-deck glass, which resulted in a differential pressure inside and outside the cockpit that finally caused the windshield to burst off the fuselage. ■