An investigation has begun into a terrifying mid-air emergency on an AirAsia flight from Perth to Bali that prompted one passenger to contact her family because she thought she was going to die.
AirAsia has apologised after the incident that forced the pilot to turn around and head back to Perth with 145 people on board.
Flight QZ535 reportedly plummeted 20,000 feet 25 minutes into the flight from Perth on Sunday when a technical issue caused the cabin to lose pressure.
The Australian Transport Safety Bureau has begun investigating the incident.
It follows an incident in June when an AirAsia from Perth to Kuala Lumpur had to return because of an engine malfunction, which the ATSB is also investigating.
Oxygen masks fell and passengers were told to get into the brace position, causing panic.
Perth woman Leah said people thought they were going to die and were saying goodbye to each other.
"I actually picked up my phone and sent a text message to my family, just hoping that they would get it," she told reporters.
"It was horrible."
Another boy said he was "really scared and thought he was going to die".
Passengers said they didn't know what was happening because most of the plane's onboard announcements weren't in English.
"The panic was escalated because of the behaviour of staff who were screaming, looked tearful and shocked," Clare Askew told reporters at Perth Airport.
"Now, I get it, but we looked to them for reassurance and we didn't get any, we were more worried because of how panicked they were."
The Malaysian budget airline issued a statement apologising and said its engineers were examining the plane at Perth.
"The safety of our guests is our utmost priority," the airline said.
"AirAsia Indonesia apologises for any inconvenience caused."
An ATSB spokeswoman said it had begun examining data from the plane's flight recorder.
The June AirAsia incident, in which the plane shook noisily and violently, prompted criticism by the Australian and International Pilots Association of the crew's reaction.
Pilot Captain Ibrahim told everyone to pray, saying "I will be saying a prayer too", but AirAsia chief executive Tony Fernandes praised him and said the Rolls-Royce made engine failure was not the airline's fault.
In July, an AirAsia flight was forced to make an emergency landing in Brisbane after a birdstrike.