More than 1,000 passengers were affected when the instrument landing system at Guangzhou Baiyun International Airport broke down on Tuesday night. 

Many flights were canceled or delayed in the provincial capital of South China's Guangdong province because of the failure, Guangzhou Daily reported.

An instrument landing system is a ground-based approach system providing precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting to enable a safe landing.? 

Airport authorities said 57 flights were affected by the breakdown. Twenty-five flights — 15 arrivals and 10 departures — were delayed for more than an hour.

Ten flights were diverted to Shenzhen and Zhuhai airports while another 10 arrivals were canceled by about 10 pm. Operations at the airport, one of the three busiest in China, returned to normal after midnight. 

One passenger was quoted as saying by the newspaper: "Our plane circled the airport for about an hour before it finally landed in Guangzhou." The unnamed passenger was returning to Guangzhou from Shanghai.

One pilot said: "All departures and arrivals have to be delayed or canceled when the instrument landing system breaks down."