Description

On 7 September 2008 a South African Airways Airbus A319 en route from Cape Town to Johannesburg at FL370 received an ECAM warning of the failure of the No 1 engine bleed system. The crew then closed the No. 1 engine bleed with the applicable press button on the overhead panel. The cabin altitude started to increase dramatically and the cockpit crew advised ATC of the pressurisation problem and requested an emergency descent to a lower level. During the emergency descent to 11000 ft amsl, the cabin altitude warning sounded at 33000ft and the flight crew activated the cabin oxygen masks. The APU was started and pressurisation was re-established at 15000ft amsl. The crew completed the flight to the planned destination without any further event. The crew and passengers sustained no injuries and no damage was caused to the aircraft.

The Investigation

An investigation was carried out by the Accident and Incident Investigation Division of the South African CAA. This found that the aircraft had been released to service the previous day with an ADD for the No 1 Engine Bleed System Inoperative and the aircraft to be operated in accordance with the corresponding MEL requirements, which were “that the No.1 engine bleed system was to be selected 'closed' and No 2 engine bleed system was to be selected ‘open’ by means of the press button switches on the overhead panel." The Captain on the last flight of the previous day nevertheless decided to select both No 1 and No 2 engine bleed switches to the ‘open’; position and in the event of an engine bleed system malfunctioning, he planned to isolate the faulty bleed system. An uneventful flight was then made to a night stop for the aircraft.