What happened
During a return flight to Emerald, the crew encountered unidentified fumes within the aircraft cabin. While the pilot maintained control of the aircraft and followed established radio procedures, the crew members experienced different physical symptoms. One crew member, seated in the rear, reported respiratory issues and nausea, while another experienced a headache. Although the pilot did not report physical symptoms, the incident may have resulted in cognitive impairment affecting decision-making and aircraft handling.
Rather than diverting to a more immediate suitable airport, the pilot elected to continue the flight to Emerald. This decision resulted in the crew being exposed to the fumes for a longer duration than might have been necessary. Furthermore, while the crew utilized pulse oximeters and was trained in the use of supplemental oxygen, they did not opt to use the available onboard oxygen supply.
The investigation
Investigators examined the aircraft for potential sources of the fumes, but no definitive cause could be determined. There were no visible leaks or smoke, and no environmental factors were identified that could have produced the fumes. Onboard carbon monoxide detectors failed to activate, and subsequent inspections by the Queensland Fire and Emergency Services (QFES) found no evidence of thermal hotspots or noxious gases. Following the event, the operator conducted inspections of the aircraft wiring and components but found no faults, and subsequent test flights failed to replicate the presence of fumes.
Findings
- The crew was subjected to cabin fumes that caused varying levels of physical and potentially cognitive impairment.
- The decision to return to Emerald instead of diverting to a closer airport extended the crew's exposure to the fumes.
- The pilot did not declare a MAYDAY or PAN PAN, nor did they request emergency services for the landing, a choice potentially linked to impaired decision-making.
- The source of the fumes remained unidentified despite extensive ground and in-flight examinations.