On 9 June 2014, shortly after take off, the crew of an Airbus A330-200 (VH-XFB) being operated by Virgin Australia on a scheduled domestic passenger flight from Perth to Sydney in day Visual Meteorological Conditions (VMC) were advised of the commencement of a 'burning odour' from an undetermined source in the rear galley area which was continuing. After about 20 minutes, during which time affected cabin crew received therapeutic oxygen to aid their recovery, the odour ceased and the flight was continued to destination without recurrence.
An Investigation was carried out by the Australian Transport Safety Bureau (ATSB).
It was established that as engine power was applied for take-off, cabin crew members at the rear of the cabin had detected a 'burning odour'. Based upon their experience of this particular aircraft type, they initially dismissed this as being relatively common and expected that they would, as usual, dissipate soon after becoming airborne. However, this time, the fumes seemed more intense than usual and appeared to grow in intensity, so the rear cabin crew contacted the cabin supervisor on the interphone and advised the situation. The fumes remained obvious in the rear cabin but not further forward.
Once the cabin crew were released from their seats by the flight crew, the cabin supervisor came back to assist with identification of the source of the fumes. Eventually, the source of the fumes was traced to a vent in the rear cabin bulkhead. A report was made to the Captain but after about 20 minutes, the fumes ceased so that by the time he came to the rear of the cabin to assess the situation, they were no longer present. He also advised that there had been no flight deck indications of a problem which might have generated fumes.
Some cabin crew members were sufficiently affected by exposure to the fumes that they were unable to complete their normal duties. The Captain considered making an en route diversion to Adelaide but since the most affected cabin crew had recovered following the administration of routinely-carried therapeutic oxygen, it was decided to complete the intended flight. Upon arrival at Sydney, a defect entry was made in the Aircraft Technical Log to the effect that acrid fumes had been evident in the rear galley area after take-off. Some of the affected cabin crew members also sought medical attention following the flight although no significant information on this was communicated to the Investigation.
Engineering inspection found that part of the insulation blanket fitted to the rear pressure bulkhead of the aircraft and made of glass wool encased in a wrapping material had collapsed and come into contact with the APU bleed air duct where it passed through the bulkhead. It was concluded that this was the source of the fumes. The wrapping had been heat-damaged and this had exposed the inner glass wool material to heat damage too. The two illustrations below show the extent of the damage. It was established that the cause of this was incorrect refitting of the insulation blanket after previous maintenance work on the aircraft.
Insulation blanket damage (left picture) adjacent to the surface of the APU bleed air duct (right picture) - reproduced from the Official Report
Safety Action taken by Virgin Australia as a result of the findings included an inspection of its other A330 aircraft, one of which was found with similar damage. Pending rectification, the two aircraft were released to service with the APU out of use.
The Investigation concluded that fumes may originate from a wide range of sources and, whilst some may appear subtle and innocuous, they are sometimes the first indication of a more serious problem. It was also noted that:
- the effect of fumes on the human body is dependent on many variables, including the nature and intensity of the fumes, and the duration of exposure.
- this incident serves to highlight the importance of treating all fumes with suspicion, and implementing a cautious and conservative response, consistent with published guidance.
The Final Report was published on 27 January 2015. No Safety Recommendations were made.