Lucky Air will sue a passenger who tossed coins at a jetliner's engine to wish for a safe flight, causing the plane to be grounded overnight at great expense, the company said on its social media account on Friday.

A Lucky Air flight from Anqing, in East China's Anhui province, to Kunming, Yunnan province, was canceled on Feb 17 after airport staff found evidence suggesting that one of the 162 passengers had attempted to throw coins into one of the plane's engines.

Two 1-yuan coins were found on the ground near the left engine during the preflight check.

Airline staff members boarded the plane and asked if anyone had tried to toss coins into the plane's engine. A man surnamed Lu later admitted that he threw the two coins at the engine as he was boarding because he believed it would bring good luck.

The flight was grounded overnight as a safety precaution and a full examination of the engine was conducted. The passengers were flown to Kunming the next day.

Lu, 28, was taken into a custody by transport police and detained for seven days.

The airline said the coin-throwing led to the cancellation of the flight, greatly inconveniencing passengers, and causing economic losses of nearly 140,000 yuan (US$20,900). The company said it will sue the passenger, as provided by law.

Ouyang Jie, a professor at Civil Aviation University of China, said the engine would quite likely be destroyed if a coin entered the engine during flight.

"The engine could tremble, lose speed and even stop in midair if a coin were sucked into its core," he said. "That would put all the passengers on board at great risk."

Twice before, elderly Chinese travelers have been caught throwing coins into a plane's engine for good luck. Both were spared prosecution because of their age.

In the first incident, an 80-year-old woman chucked coins worth 1.7 yuan into the engine of a China Southern Airline plane at Shanghai's Pudong airport in June 2017, causing a five-hour delay and a million yuan in damage. The woman was not charged with a crime because of her age.

"We have seen air travelers create other safety problems in recent years, including opening emergency doors and assaulting cabin crew," Ouyang said. "It's necessary to put the wrongdoers on a black list and ban them from air travel."