An air quality event aboard a QantasLink Boeing 717-200 saw the aircraft land in Hobart with both flight crew affected by hypoxia-like symptoms.

The incident has seen National Jet Systems, which operates under the QantasLink brand, update training and safety guidance about cabin air quality issues, according to the Australian Transport Safety Bureau.

VH-NXM Qantaslink

Source: Wikimedia Commons

VH-NXM, the 717-200 involved in the hypoxia event. The ATSB says that donning oxygen masks can be key for crews to maintain physical and mental capacity

On 6 June 2023 the aircraft, VH-NXM, was operating a service from Sydney to Hobart, on the sland of Tasmania. After departing Sydney two cabin crew in the front of the cabin detected a “strong chlorine odour” near the forward galley.

They reported this to the flight crew, who had not detected the smell. At cruising altitude, the crew conducted a company air quality event procedure.

At 21:08 local time, about 10nm (18.5km) from Hobart at an altitude of 4,000ft, the captain and first officer noticed a chlorine odour, likely coming from the air-conditioning vents.

“About 30 seconds later, while the flight crew were configuring the aircraft for landing on runway 30, the captain noticed quickly developing adverse effects on vision, mental capacity, and movement, and self-assessed as unable to safely fly the aircraft,” says the enquiry.

“The captain later described the symptoms as fogginess of thought, confusion, deteriorating situational awareness, weakness and tingling in the arms and legs, and narrowing of vision.”

The captain transferred control to the first officer, who saw that the captain looked pale, but not incapacitated.

Immediately before landing, however, the first officer had difficulties keeping the aircraft lined up and felt hazy. Still, he landed the aircraft. Subsequently, he said that he felt it was safer to land instead of donning the oxygen mask and conducting a go-around – neither crewmember used supplemental oxygen during the incident.

“Both flew crew members were partially incapacitated during the landing and subsequent taxi to the parking bay,” says the ATSB.

As a result, the operator has updated simulator training around pilot incapacitation, as well as approach, landing, and taxiing while using oxygen. Other procedures were also updated, including updates to the manual for the Airbus A220, the type replacing the 717 in QantasLink’s fleet.

“Airborne contaminants may result in the rapid onset of incapacitation, which although possibly subtle, can significantly affect the safety of flight,” says the ATSB.

“Physical or cognitive incapacitation can occur for many reasons and may be difficult for others, or even the sufferer of, to detect and respond to. Flight crews should therefore be alert to the potential hazards posed by odours and fumes and not hesitate to use supplemental oxygen.”

None of the 54 passengers and five crew was injuring during the incident, which the ATSB rates as ‘serious.’