What happened
During the flight, the pilot experienced physical symptoms and cognitive impairments. Following the incident, subsequent ground runs of the aircraft revealed elevated levels of carbon monoxide (CO) within the cabin environment. The symptoms experienced by the pilot were consistent with the effects of CO poisoning, a finding supported by a positive result from a CO chemical spot detector and medical blood tests.
The investigation
Investigators examined the aircraft for potential pathways through which exhaust gases could enter the cockpit. While no obvious breaches or structural openings were identified that would allow for such ingress, post-incident repairs were performed on the exhaust stack and the scat hoses. Once these specific components were repaired, the elevated levels of carbon monoxide during ground operations were resolved, linking the leak to these items.
Medical analysis of the pilot showed a mildly elevated level of carboxyhaemoglobin (COHb). Although the severity of the pilot's symptoms was noted as being somewhat inconsistent with standard medical literature for that specific COHb level, the investigation acknowledged that individual physiological reactions vary and that cognitive impairment can occur at levels as low as 3 per cent.
Findings
- An exhaust leak likely allowed elevated levels of carbon monoxide to enter the aircraft cabin.
- The exposure to carbon monoxide resulted in the mild incapacitation of the pilot.