Safety Action
As a result of this occurrence, the Bureau of Air Safety Investigation is currently analysing two possible safety deficiencies. The deficiencies identified involve the use of oxygen masks and emergency descent profile awareness by cabin crew during cabin decompression, and the carriage of additional Passenger Service Unit tools in the mid cabin area of the aircraft.
Summary
The Airbus A320 on a flight from Hobart to Melbourne had commenced descent from flight level (FL) 350 to FL210 when the aircraft cabin altitude began to rise rapidly. The co-pilot was unable to control the cabin pressurisation manually.
The flight crew donned oxygen masks, and the pilot in command requested and was given a clearance by air traffic control for an immediate descent to 10,000 ft. During the descent, the passenger oxygen masks deployed. The aircraft subsequently made an uneventful approach and landing at Melbourne Airport.
The operator found that the electronic control of the pressurisation outflow control-valve had failed, allowing the valve to remain in the fully open position. The valve was changed and the aircraft returned to service. The valve has been returned to the manufacturer in France for further evaluation.
Occurrence summary
| Investigation number | 199800707 |
|---|---|
| Occurrence date | 08/03/1998 |
| Location | 19 km SSE Wonthaggi, (VOR) |
| State | Victoria |
| Report release date | 24/07/1998 |
| Report status | Final |
| Investigation type | Occurrence Investigation |
| Investigation status | Completed |
| Mode of transport | Aviation |
| Aviation occurrence category | Air/pressurisation |
| Occurrence class | Incident |
| Highest injury level | Minor |
Aircraft details
| Manufacturer | Airbus |
|---|---|
| Model | A320 |
| Registration | VH-HYB |
| Serial number | 023 |
| Sector | Jet |
| Operation type | Air Transport High Capacity |
| Departure point | Hobart, TAS. |
| Destination | Melbourne, VIC. |
| Damage | Nil |