Air traffic control halted briefly at Vietnam's busiest airport

Many flights were unable to take off or land at Tan Son Nhat International Airport in Ho Chi Minh City as the air traffic control (ATC) system there was down for nearly 20 minutes on Tuesday morning, local online newspaper Tuoi Tre (Youth) News reported.

The Civil Aviation Authority of Vietnam (CAAV) confirmed to the newspaper that the incident occurred at 7:47 a.m. local time and lasted for 18 minutes.

"The ground service personnel could contact none of the planes that were about to land or take off during that time," CAAV chief Lai Xuan Thanh said.

The general director of a carrier told the newspaper that a couple of flights operated by his airline failed to leave or arrive at the airport after 8:00 a.m. The affected flights had to fly around waiting for contact to resume, or land at an alternative airport.

The incident was possibly a case of interfered radio frequency, according to the Vietnam Air Traffic Management Corporation. The frequencies of all channels of the ATC system were interfered by a strong, unknown frequency at the time of the incident, which disrupted the system.

The CAAV is cooperating with the Authority of Radio Frequency Management to look into the case, it said in a press release on Tuesday afternoon.

Tan Son Nhat is Vietnam's largest airport in terms of capacity, handling more than 20 million passengers a year. On November 20 last year, the airport suffered an hour-long blackout which disabled the radar system that controls air traffic at the terminal, affecting 92 flights. Endi