MANILA, Philippines – Multiple flights departing and arriving in the Ninoy Aquino International Airport (NAIA) may experience delays due to a “potential problem” with the software of the Air Traffic Management Center (ATMC).

“During the regular monitoring today at the Air Traffic Management Center, the Civil Aviation Authority of the Philippines (CAAP) identified a potential problem with the software of ATMC. To ensure safety of the flying public, CAAP decided to be conservative and manage the operations by providing longer separation of departing flights,” CAAP said in an advisory on Monday, May 20.

As of 2:02 pm, CAAP public information officer Karen Villanda said the problem at the ATMC has been resolved and that “regular flight operations are now being restored.” It may, however, take some time for airlines to clear up flight delays.

Earlier, at around 12 noon on Monday, CAAP temporarily suspended all departing and arriving aircraft at NAIA. The agency then said it had put in place an “air traffic management contingency procedure” to ensure safety, resulting in longer separation intervals for departing flights. Villanda said that both traffic coming in and out of Manila may be affected, although she clarified that the communication and surveillance at the ATMC “remain available and unaffected.”

Affected flights

As of 3 pm on Monday, 36 domestic flights and 20 international flights in NAIA have been affected, according to the Manila International Airport Authority (MIAA). To facilitate airline flight recovery operations, the runways of NAIA will operate for twenty-four hours straight. 

Passengers are advised to check with their airline’s social media platforms and websites for timely updates.

Cebu Pacific released an advisory that “flights departing and arriving at NAIA may experience delays due to issues related to the software at the ATMC which are affecting operations.” In another advisory at 6 pm, the low-cost airline announced the cancellation of 13 flights:

• 5J 389/390: Manila – Cagayan De Oro – Manila
• 5J 455/456: Manila – Iloilo – Manila
• 5J 487/488: Manila – Bacolod – Manila
• 5J 557/558: Manila – Cebu – Manila
• 5J 955/956: Manila – Davao – Manila
• DG 6839/6840: Manila – Siargao – Manila
• 5J 647/648: Manila – Puerto Princesa – Manila
• 5J 651/652: Manila – Tacloban – Manila
• 5J 653/654: Manila – Tacloban – Manila
• 5J 746/747: Manila – Hanoi – Manila
• 5J 759/760: Manila – Jakarta – Manila
• 5J 773/774: Manila – Pagadian – Manila
• 5J 915/916: Clark – Boracay – Clark

“The ATMC technical issue has now been resolved, but operations of airlines will take some time to normalize, resulting in further disruptions. As a result, CEB needed to make additional cancellations. Aside from these, there are also some flights that are subject to sunset limitations at certain destinations,” Cebu Pacific said in the later advisory.

As of 2:00 pm, four AirAsia domestic flights and one AirAsia international flight were also put on hold, as shown in the table below. AirAsia Philippines communications and public affairs head Steve Dalisan added that although there may be minor delays, the situation is expected “to normalize very soon.”

Meanwhile, Philippine Airlines (PAL) said in a statement that its flight operations were “normalizing” after the disruption caused by the software issue. However, PAL has had to cancel the following domestic flights:

• PR 2135/2136: Manila – Bacolod – Manila
• PR 2045/2046: Manila – Caticlan – Manila
• PR 2043/2044: Manila – Caticlan – Manila
• PR 2823/2824: Manila – Davao – Manila

“With the restoration of Manila radar operations by government authorities, we are working towards normalizing our flight operations. We are closely coordinating with the aviation authorities on the adjustment of flight schedules and clearances,” PAL spokesperson Cielo Villaluna said.

What happened?

CAAP has yet to clarify what the technical problem was.

However, an advisory by Cebu Pacific pinned the issue to the “main flight data processor of the ATMC,” which limited the number of flights allowed to operate between midday and 2:21 pm.

The MIAA also said in a statement that CAAP “monitored an issue with their ATMC software, necessitating the implementation of longer distance separation between flights at the NAIA.” 

MIAA, the government agency that operates Manila’s international airport, also advised passengers to expect congestion at the pre-departure gates and baggage claim areas. Terminal managers have been directed to provide additional seating in the meantime.

This was not the first time that glitches with CAAP’s air traffic management system have affected flights all over the country. On January 1, 2023, the entire Philippine airspace was shut down for hours due to issues with the ATMC, leaving more than 78,000 passengers stranded on New Year’s Day. (READ: What caused the January 1 air traffic mess and what should be done about it?) – Rappler.com