A new air traffic control (ATC) team has been installed to the Zamboanga City International Airport after the relief of four air traffic personnel, who caused the delayed landing of at least two domestic flights on Friday morning.

Director General Ruben Ciron, chief of the Civil Aviation Authority of the Philippines (CAAP), said he immediately relieved the ATC team's supervisor and three of his men for the almost one hour delayed landing of Philippine Airlines flight 123.

"They came late the two air traffic controllers, and because of what happened, I ordered the relief of their supervisor and three controllers," Ciron told radio dzMM in an interview.

The CAAP said Friday that PAL flight 123, which was carrying at least 140 passengers, hovered above the Zamboanga airport for at least 30 minutes because the duty air traffic controllers failed to come up the ATC tower on time.

Ciron said two air traffic controllers were supposed to report to the tower at 6 a.m. He said the PAL flight was scheduled to land 6:45 a.m., but it came 45 minutes earlier.

Reports on Friday said that the air traffic controllers were late for at least an hour, causing the delay.

Two more commercial flights of Cebu Pacific from Cebu and Manila almost suffered the same fate but the pilots opted to land despite not having clearance so flights could be on time.

Planes should ask for visual clearance from air traffic controllers before making the landing.

Ciron said the simple case of tardiness could have been fatal for the hundreds of passengers.

He assured the public that the erring air traffic controllers will be given "stiff punishment." He also promised to do everything he can to prevent a similar incident.

He said he had sent a team to Zamboanga City to further investigate the incident. With a report from Leila Vicente, ABS-CBN Zamboanga