https://www.atsb.gov.au/publications/investigation_reports/2022/aair/ao-2022-002
Summary
The ATSB has commenced a transport safety investigation into a cabin crew incapacitation occurrence involving Fokker F100, registered VH-FNU, near Mount Magnet Aerodrome, Western Australia on 27 December 2021.
The aircraft was being operated on a scheduled passenger flight between Newman and Perth, Western Australia with 5 crew and 7 passengers. During cruise at flight level 340 (34,000 ft), a cabin crew member began to feel unwell and was treated with portable oxygen. The flight crew climbed to flight level 350. A few minutes later the other two cabin crew members also felt unwell and reported to the flight crew that they suspected possible hypoxia.
The first officer later reported that they had also felt light-headed and experienced slight nausea. As a precaution, the flight crew donned oxygen masks, manually deployed the passenger oxygen masks and conducted an emergency descent to 10,000 ft. The aircraft landed at Perth Airport and one cabin crew member was taken to hospital for assessment.
The investigation is continuing. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken.