An airline passenger had to be restrained by flight stewards after he threatened to bring down the plane with the power of his mind.An Australian reporter on the flight said passengers sitting near the man believed he was under the influence of drugs or alcohol or both, and had religious delusions.Stewards on the Qantas flight from Sydney to Singapore handcuffed the man's arms and legs about five hours into the 7½-hour flight, reports ABC.Police in Singapore boarded the flight and arrested the man after passengers disembarked. He is being held for questioning.A spokesman for the Australian airline said the passenger was restrained in his chair after behaving in a "threatening and disruptive manner".A spokesman for Singapore's police said they were still holding the man and his actions were under investigation.The incident comes on the same day as another long-haul Qantas flight was grounded in Melbourne after a cockpit window cracked during a flight from Los Angeles.The Australian airline has faced a string of technical problems on its flights in recent months - from tyres blowing out during landing to engine troubles.Source: orange news