Man proposes as AirAsia flight plunges 20,000 feet

One of the passengers on an AirAsia flight that plunged 20,000 feet took the opportunity to pop the question to his girlfriend during the terrifying experience.

Flight GZ535 from Perth to Bali lost air pressure abruptly only an hour into its journey on Sunday morning (local time).

Passengers were told to brace as the aircraft plummeted 20,000 feet to get back to breathable air.

In the panic, Londoner Chris Jeanes turned to his girlfriend Casey Kinchella, from Perth, and asked her to marry him, according to NBC News.

"Luckily she said 'yes'. We both reconfirmed with each other when we were on the ground," he told media.

They were able to disembark with the story of a lifetime, but not all of their fellow passengers were as enthused.

One told 7 News the staff on board were "screaming and looked tearful", adding more terror to an already traumatising experience.

The airline is investigating the case of the technical issue.