Qantas Pilot Incapacitated Midair After Sudden Cabin Depressurization

A pair of Qantas pilots had a harrowing experience after their aircraft suddenly depressurized mid-flight, causing a pilot to become incapacitated, forcing an emergency landing.

A Qantas Boeing 737-300 freighter was flying from Brisbane (BNE) to Melbourne (MEL) on Wednesday when the pilots received a "wing body overheat warning," resulting in a sudden depressurization of the aircraft.

"The crew donned oxygen and descended to 20,000 ft," the Australian Transport Safety Bureau (ATSB) wrote in its report of the incident. "The First Officer was subsequently incapacitated and the Captain descended to 8,000 ft and diverted the aircraft to Canberra."

The aircraft, registered VH-XMO is operated by Express Freighters Australia, which is a fully owned subsidiary of Qantas. As it was a cargo flight, there were no passengers on board.

The aircraft made its way to an altitude of 8,000 ft, which is standard operating procedure, since that elevation contains more oxygen, making it easier to breathe.

FlightRadar24 shows the diversion made over the eastern Australian town of Narranderaa, a little more than halfway through its scheduled flight path. Emergency services were on the ground when the aircraft made an emergency landing at Canberra (CBR) airport at 12:04am. The aircraft did not receive any damage during the event.

"The Boeing 737 freighter diverted into Canberra on Wednesday night following a fault with the on-board air conditioning system that affected the ability to maintain pressure in the cabin," a Qantas spokeswoman told the Sydney Morning Herald.

Other problems that may cause depressurization include cracks in the window or fuselage and a poorly sealed door.

Although neither were injured, the pilots went to the hospital as a precaution, but were quickly discharged the spokeswoman said. Qantas is conducting its own investigation into the incident alongside the ATSB's own investigation.

"As part of the investigation, the ATSB will collect and examine information on the aircraft’s flight data recorders and interview maintenance and flight crew," the ATSB said. "Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify those affected and seek safety action to address the issue."

This summer has seen a number of incidents of faulty air conditioning systems on aircraft leading to extreme cabin temperatures — with some events leading to passengers passing out on board.