Aviation safety investigations & reports

Carbon monoxide indication during flight involving Piper PA-28, VH-PZG near Bankstown Airport, New South Wales, on 8 March 2021

Investigation number:
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase


Download Final Report
[Download  PDF: 429KB]

What happened

On 8 March 2021, the crew of a Piper PA-28 aircraft, registered VH-PZG, were conducting a dual training flight from Bankstown Airport to the Bankstown training area, New South Wales.

At the top of climb, at about 4,000 ft near Warragamba Dam, the instructor detected a faint exhaust gas smell and recalled feeling a little more tired than when they took off and mildly lightheaded. The instructor then looked up at the carbon monoxide detector and observed a localised discolouration (indicating the likely presence of carbon monoxide in the cabin).

The instructor opened all fresh air vents and windows, and ensured the heater was off. They then advised the student of the positive indication and decided to return to Bankstown. The student continued to fly the aircraft back while the instructor monitored the situation and detector.

The aircraft landed safely at Bankstown and the crew were taken to hospital for medical examination.

What the ATSB found

The ATSB found that the disposable carbon monoxide detector had indicated elevated levels of carbon monoxide in the cabin during the flight. Positive carbon monoxide indications were also reported in two previous flights nine months prior. However, subsequent post-incident inspections and test flights were unable to replicate the conditions nor determine the source of the carbon monoxide.

Safety message

Carbon monoxide (CO) is a colourless and odourless gas, and its presence may not be detected until the development of physical symptoms and/or cognitive effects. Therefore, operators and owners of piston-engine aircraft are strongly encouraged to install a CO detector with an active warning to alert pilots to the presence of elevated levels of CO in the cabin. Should any smell or sensation of illness develop, pilots should check their CO detector, ensure cabin heat has been turned off, open all fresh air vents and windows, make prompt decisions to land as soon as possible, and use all available resources for assistance. Further information on CO poisoning and detectors can be found at the following:

Are you protected from carbon monoxide poisoning?

Carbon Monoxide: A Deadly Menace

Detection and Prevention of Carbon Monoxide Exposure in General Aviation Aircraft

Download Final Report
[Download  PDF: 429KB]

The investigation


The Australian Transport Safety Bureau (ATSB) is investigating a reported partial pilot incapacitation involving a Piper PA-28, VH-PZG, near Bankstown Airport, New South Wales on 8 March 2021. 

The aircraft departed Bankstown for a dual training flight in the Bankstown training area. About half an hour into the flight the instructor started to feel lightheaded and less focused than normal. The instructor examined the carbon monoxide card detector and observed a discolouration (positive indication). The crew then opened all fresh air vents and returned the aircraft to Bankstown.

As part of the investigation, investigators will interview the crew and review aircraft maintenance information.

A final report will be released at the conclusion of the investigation.

Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate safety action can be taken. 

General details
Date: 08 March 2021   Investigation status: Completed  
Time: 8:30 ESuT   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): near Bankstown Airport   Investigation phase: Final report: Dissemination  
State: New South Wales   Occurrence type: Flight crew incapacitation  
  Occurrence category: Incident  
Report status: Final   Highest injury level: None  
Anticipated completion: 4th Quarter 2021    

Aircraft details

Aircraft details
Aircraft manufacturer Piper Aircraft Corp  
Aircraft model PA-28  
Aircraft registration VH-PZG  
Serial number 28-7916193  
Type of operation Flying Training  
Sector Piston  
Damage to aircraft Nil  
Departure point Bankstown, NSW  
Destination Bankstown, NSW  
Last update 14 October 2021