A Qantas flight making its way from Adelaide to Melbourne dropped 26,000 feet suddenly after the cabin became depressurized, according to the Agence France Presse.
The Boeing 737 was roughly 30 minutes from Melbourne when oxygen masks fell from the plane's ceiling as the plane dropped from its cruising altitude of 36,000 feet to a whopping 10,000 feet.
The culprit? The plane's air conditioning system. An airline spokesman told the AFP: "There are two air conditioning systems on the aircraft -- one of them failed at the cruising altitude, that's when they started to descend."
Passengers on the plane had quite a fright. A passenger told Fairfax radio that "there was a little bit of panic down the back of the plane and some of the passengers needed to be comforted by the hostesses. One lady in particular was fairly panicked."
Fortunately, the plane landed without incident and no one was injured.
It's been a rough couple of months for Qantas planes: In August, a Sydney-bound flight was forced to return to the San Francisco airport 45 minutes into the flight after the plane's engine blew. And in November, a flight from Singapore to Sydney had to make an emergency landing after one of the plane's engines shut down, causing the airline to ground all A380s.