Four security officers at Vinh Airport, Nghe An Province, have been fined after a man with mental problems boarded a plane.

The Vietnam Airlines crew was working as usual when noticing a strange man on the plane. When the man was unable to provide the boarding pass, the crew then called the security.

The man was later identified as a 21-year-old student at Vinh University. He has taken a leave of absence from the university for the treatment of his mental illness. His family has submitted the required health checks and papers to prove that he was being treated at a local hospital and get him released.

According to the authorities, he climbed the wall into the airport and walked through several security checkpoints before boarding the plane.

The Civil Aviation Administration of Vietnam is investigating the case and reviewing airport security.

Tran Hoai Phuong, director of Northern Airport Authority said four security guards were fined VND10m (USD439) each and had their licenses withdrawn for two months. A member of ground staff was fined VND4.5m and Vinh International Airport was fined VND40m.

Dtinews