Dense fog forced several flights en route airports in northern Vietnam to reroute on Thursday evening.
The fog blanketed airports in many northern localities from 7:30 pm on Thursday, preventing airports in these areas from receiving planes, director of the Civil Aviation Authority of Vietnam (CAAV) Dinh Viet Thang told Tuoi Tre (Youth) newspaper at 10:40 pm the same night.
At 10:20 pm, visibility measured at Noi Bai International Airport in Hanoi was only 700-800 meters, the cloud ceiling was 50-60 meters, and northeast wind speed was 1-2 meters per second.
“The cloud ceiling is too low,” Thang said.
"It is below landing standards, so only aircraft taking off from Noi Bai Airport are allowed and planes scheduled to land are prohibited because it is not safe.
“About 30 domestic and international flights to northern airports had to be diverted to Van Don and Da Nang International Airports [in northern Quang Ninh Province and central Da Nang City, respectively].”
Van Don Airport was also affected by the fog at times and unable to receive aircraft, but weather conditions at the Quang Ninh-based airport improved later, with strong winds blowing the fog away, permitting it to receive a number of coming flights on Thursday evening.
In addition to Noi Bai, the fog and low cloud ceiling prevented Cat Bi Airport in northern Hai Phong City and Vinh Airport in north-central Nghe An Province from receiving incoming aircraft.
Some flights to these two airports had to change their destination to Da Nang International Airport.
Fog and low clouds, which are dangerous weather conditions in aviation, often occur during winter in the northern region, according to Thang.
Many passengers often think airlines use bad weather as an excuse for flight delay or cancellation, Thang said.
“In fact, bad weather really did affect northern airports,” the CAAV director explained.
“Although it might be possible for airplanes to take off, it is not safe for them to make land.”