A Qantas passenger threatening to bring down the plane with the 'power of his mind' had to be restrained by cabin crew.
The man was believed to be under the influence of drugs or alcohol, and was also said to be delusional.
He reportedly threatened to use the 'power of his mind' to bring down the plane, according to an ABC report.
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Stewards onboard the flight from Sydney to Singapore handcuffed the man's arms and legs for the remainder of the flight.
The man was suffering some kind of delusion, and people sitting near him said he was threatening to bring down the flight.
Singaporean authorities boarded the flight after passengers disembarked.
Meanwhile a Qantas plane that was flying to Los Angeles was grounded in Melbourne, after cracks appeared in its cockpit window.
A pilot noticed a crack in the outer panel of the side cockpit window after it took off, and the jet returned and landed safely on Monday morning.
The incident affected 239 passengers who will have been delayed 15 hours if the plane leaves at its rescheduled time of 1am (AEST) on Tuesday.
In a statement, Qantas said the crack did not pose a major safety threat and it was safe for the jet to continue flying.
"However, as a precaution, the window was changed after the aircraft arrived in Melbourne," the statement said.
"Qantas apologises for the inconvenience caused."
It follows a series of incidents in the past week that have forced Qantas flights to be grounded.
