Aviation occurrence briefs

Cabin depressurisation involving Airbus A330-303, 233 km NE of Forrest Airport, WA, on 14 April 2018

Status: Completed
Investigation completed


Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.

What happened

On 14 April 2018, at about 0158 Western Standard Time (WST), an Airbus A330-303 was en-route from Perth, Western Australia (WA) to Sydney, New South Wales (NSW) with 297 passengers and 11 crew members on board.

At the time of departure from Perth Airport, there was a known fault with one of the engine bleed air systems on the aircraft, which was permitted under the minimum equipment list. During cruise at flight level (FL) 390[1], the crew received an ECAM[2] ‘ENG 2 BLEED FAULT’ message, indicating a fault with the second engine bleed air system. The crew followed the ECAM actions to reset the system, but this was unsuccessful in restoring cabin pressurisation. Loss of the second bleed air system resulted in the depressurisation of the cabin.

The crew declared a PAN PAN[3] and received clearance from air traffic control (ATC) to conduct a descent to 10,000 ft. Shortly after commencing the descent, the crew received an ECAM ‘CAB PR EXC CABIN ALT’ message, indicating an increase in cabin pressure, which requires a mandatory emergency descent. Oxygen masks deployed in the cabin, and the crew initiated the descent to 10,000 ft. Flight and cabin crew conducted regular passenger announcements throughout to keep passengers informed of the situation.

Once the aircraft was level at 10,000 ft, the flight crew continued to follow the non-normal procedure checklists and were able to reset the no. 2 engine bleed air system. The cabin crew manager informed the flight crew that there were no passenger injuries during the descent, however they had observed fumes and mist in the cabin, both of which dissipated after a short time.

The flight crew had initially intended to divert the aircraft to Adelaide, however, due to poor weather conditions and the fact that the no. 2 engine bleed air system was reset, the decision was made to divert the aircraft to Melbourne. The flight crew contacted ATC and received a clearance to climb to FL170, as requested.

The flight crew updated the cabin services manager with the latest information, and regular passenger announcements were made to keep passengers informed throughout the remainder of the flight. The aircraft landed at Melbourne without incident, where engineers subsequently replaced the no. 2 engine bleed valve and solenoid.

Safety message

This occurrence provides a good example of effective handling of non-normal, in-flight indications. It demonstrates that a positive outcome can be achieved through a combination of following documented procedures, information sharing between flight and cabin crew and regular, clear passenger communications.

About this report

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.


  1. Flight level: at altitudes above 10,000 ft in Australia, an aircraft’s height above mean sea level is referred to as a flight level (FL). FL 390 equates to 39,000 ft.
  2. Electronic centralised aircraft monitor (ECAM): Electronic system used to monitor and display aircraft systems information and provide required flight crew actions in most normal, abnormal and emergency situations.
  3. PAN PAN: an internationally recognised radio call announcing an urgency condition which concerns the safety of an aircraft or its occupants but where the flight crew does not require immediate assistance.
General details
Date: 14 April 2018   Investigation status: Completed  
Time: 01:58 WST    
Location   (show map): 233 km NE of Forrest Airport    
State: Western Australia    
Release Date: 04 July 2018   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Airbus  
Aircraft model A330-303  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Last update 12 December 2018