What happened
On 10 June 2000, an Airbus A3/2-231, registration G-DJAR, was operating a scheduled passenger flight from London Gatwick to Palma, Majorca. The flight crew had previously operated the same aircraft on a positioning flight from Manchester to Gatwick, during which the aircraft had already experienced a loss of cabin pressurisation.
During the climb to cruising altitude, specifically passing Flight Level 300, the crew heard a loud resonance. This was immediately followed by a rapid decompression event. The cabin altitude rose quickly, peaking at 14,000 feet. In response, the flight crew initiated emergency procedures, including donning oxygen masks and performing an emergency descent. The aircraft levelled at 10,000 feet before returning to Gatwick. There were no fatalities, though minor injuries were reported among the 176 passengers.
The investigation
The investigation focused on the failure of the air conditioning system and the maintenance performed prior to the flight. Investigators found that the number 2 air conditioning pack's blow-out panel had been displaced due to overpressure. The flexible bellows section of the outlet duct had detached from its aft end. This detachment caused the duct to flutter violently, leading to further damage.
Crucially, the investigation revealed that the maintenance performed at Gatwick was improper. Following the previous day's pressurisation failure, an engineer had used glass-fibre reinforced adhesive tape and tie-wraps to secure the duct because a proper metal band clamp was unavailable. This repair was performed without proper engineering authority or a formal concession. Furthermore, the non-return valve (NRV) was found to be broken, a damage likely sustained during the previous day's flight, which had gone undetected because the crew's initial report was not fully communicated to the rectifying engineer.
Findings
- The primary cause of the decompression was the detachment of the flexible bellows duct from the air conditioning pack outlet.
- The maintenance repair using adhesive tape and tie-wraps was unapproved and inadequate for the pressure loads encountered.
- The non-return valve had been damaged during a previous flight segment, which allowed the loss of pressure once the duct failed.
- Maintenance personnel were under significant pressure to return the aircraft to service due to scheduling difficulties.
- The airline's reliability monitoring system failed to identify the recurring issues with the number 2 air conditioning pack.