History of the Flight
The flight departed from Islamabad at 0808 GMT. During cruise at flight level 320 (approximately 32,000 feet), the 'Excess Cabin Altitude' warning appeared on the Electronic Centralized Aircraft Monitor (ECAM). Per the checklist, the crew should have descended below FL 100 (10,000 feet), but instead they attempted to reset the cabin pressurization system. This resulted in all passenger oxygen masks deploying. The aircraft landed at Jinnah International Airport, Karachi, at 0955 GMT.
Injuries and Damage
No injuries were reported among passengers or crew. The aircraft sustained no damage.
Personnel Information
The captain, born 4 August 1973, held an Airline Transport Pilot License (ATPL) and had 971 hours on the A320. The first officer, born 4 March 1985, held a Commercial Pilot License (CPL) with 1212 hours on the A320. Both were medically fit at the time of the incident.
Aircraft Information
The aircraft was an Airbus A320-200, registered AP-BLV, with serial number 2758. It was manufactured in April 2006 and had accumulated 35,600 flight hours and 17,116 cycles. The aircraft was maintained in accordance with Pakistan Civil Aviation Authority regulations.
Technical Findings
Post-flight examination revealed that the cabin pressure controller number 2 (CPC #2) was suspected faulty. It was removed and sent for tear-down analysis, which showed ageing effects on soldered connections of integrated circuits, attributed to its high operating time of 38,162 hours. The outflow valve and other pressurization components functioned normally during ground tests. The flight data recorder and cockpit voice recorder were successfully downloaded and used in the investigation.
Previous Occurrences
The CPC #2 fault had been reported on three earlier flights: 2 October 2017 during climb, 3 October 2017 during cruise, and 8 October 2016 during cruise. Ground tests conducted at those times were normal.