OXYGEN masks hindered communication between cabin crew aboard a plane forced to land at Williamtown earlier this year, an investigation into the incident has noted.
The incident has sparked a fleet-wide inspection and operational test of Virgin Australia aircraft’s oxygen mask integrated microphones, according to the Australian Transport Safety Bureau’s report.
The Sydney-bound flight from Port Macquarie landed unexpectedly at Williamtown after smoke was detected in the cockpit on February 22. The alert was raised after the cockpit’s master warning went off moments after the automatic shift from the first static inverter to the second due to a fault.
“As the flight crew fitted the oxygen masks, they detected a strong electrical type burning odour and observed faint wispy smoke within the cockpit,” the Bureau’s report said. The captain declared a mayday to Williamtown’s air traffic control from about 65 kilometres away. None of the four crew members or 23 passengers were injured.
The fault that sparked the smoke has been attributed to a capacitor within the plane’s static inverter.
Problems with the static inverter had been flagged moments before the Virgin Australia ATR 72-212A’s cockpit master warning sounded an alert about electrical smoke.
But the captain and senior cabin crew also expressed concerns about oxygen masks leaving their voices “heavily distorted” during the incident, which they say led to misunderstandings that increased their workload.
“After the initial briefing from the captain, the [cabin crew] did not realise there was a smoke issue and believed the aircraft was experiencing an unspecified ‘leak’,” the crew’s comments included in the report state.
“However, as the required actions were similar to those required for the smoke
event in progress, the misunderstanding did not impact on the management of the cabin during
The Bureau credited the effective training and procedures for emergencies with helping to limit the effect of the communication breakdowns. “Despite the communications difficulties and the inaccessible cabin preparation cards, the cabin crew were able to effectively prepare the cabin during the diversion and manage the subsequent precautionary disembarkation,” the report concludes. “This enabled all aircraft occupants to disembark the aircraft quickly and without injury.”
The incident also led to manufacturer changes in the testing on some of their capacitors, which had been subject to a bulletin in December 2016 that “was classified as a minor change” and did not imply safety risks.