MANILA — The Civil Aviation Authority of the Philippines (CAAP) on Tuesday acknowledged that while the country's air traffic system was "not completely obsolete", upgrades are necessary after a technical glitch forced hundreds of flights in and out of Manila to be cancelled, diverted or delayed on New Year's Day.

Transportation department secretary Jaime Bautista earlier said the air traffic management center, which controls inbound and outbound flights at the Ninoy Aquino International Airport (NAIA), "went down" due to a power outage that resulted in the loss of communication, radio, radar and internet.

Some 56,000 passengers were stranded on Sunday due to the incident.

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The air traffic management system is in its so-called "midlife" and is "constantly undergoing regular maintenance," said CAAP deputy director-general Capt. Edgardo Diaz.

"Hindi pa naman [ito] completely obsolete though we need upgrades to make sure na siya ay makatutugon sa lahat ng pangangailangan sa ngayon," Diaz said in a public briefing.

"Maganda ang performance niyan. Ang nangyari lang ay nawalan tayo ng power kaya bumagsak ang kanyang operation. Pero nang manumbalik na ang kanyang operation, naibalik natin siya sa tamang takbo niya," he added.

(This is not yet completely obsolete though we need upgrades to make sure that it could respond to all current needs. Its performance is good. It's just that we lost power, so its operations went down. But when its operation was restored, it ran properly.)

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The agency's engineers are still estimating the cost of upgrades or potential repairs for the air traffic management system.

"That is being coordinated... to find out kung ano po talaga ang kailangang ikumpuni, ano ang dapat palitan, at ano ang magiging rekomendasyon," he said.

(That is being coordinated... to find out what needs to repaired or replaced, and what the recommendation will be.)

Video from PTV

CAAP's uninterruptible power supply is now working, with a backup also running, Diaz said.

He said CAAP is also coordinating with government agencies for assistance to prevent a repeat of Sunday's flight mess.

"In place yung procedures natin, including the contingency procedures just in case it happens again, magiging handa tayo diyan sa pagtugon sa kahit ano mang puwedeng mangyari," Diaz said.

(Our procedures are in place, including the contingency procedures just in case it happens again, we will be ready to respond to any eventuality.)

CAAP is prepared to face any congressional inquiry regarding the incident, Diaz said. Malacañang earlier said a "thorough investigation is being conducted by appropriate agencies."

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The radar and communication system is used by aviation authorities to monitor the location of planes and man the traffic airspace capacity entering or leaving the Philippine air space. The upgraded system was inaugurated in 2018.

The outage hit as many people began returning to the capital for work and school after the Christmas and New Year break.

There were chaotic scenes at check-in counters across the country as thousands of people tried to re-book tickets or find when their flights might take off.

Others who had boarded their aircraft before the glitch was announced waited for hours and were then disembarked.

Tycoon Manny Pangilinan tweeted that he had been flying from Tokyo to Manila when the plane was diverted to Haneda due to "radar and navigation facilities" going down.

"6 hours of useless flying but inconvenience to travelers and losses to tourism and business are horrendous. Only in the PH. Sigh," Pangilinan wrote.

— With a report from Agence France-Presse