The Asia Pacific region is progressing toward a cooperative air traffic management (ATM) environment, but significant challenges remain to achieving that vision, regional aviation officials said Tuesday at the Singapore Airshow.

Arun Mishra, director of the Asia-Pacific office of the International Civil Aviation Organization (ICAO), could not specifically say when the region will have a unified ATM system comparable to the Single European Sky or the NextGen concept being pursued in the U.S. “I admit I don’t have an answer; I can’t give you a date,” he said. “The good news is we have taken elements of this program and we are progressing on that.”

Mishra and Simon Li, deputy director of civil aviation with the Hong Kong Civil Aviation Department, spoke at an event sponsored by U.S. communications technology company Harris Corporation (CS22). They outlined the barriers to achieving a unified ATM system for the region, as well as some of the progress nations are making.

Mishra said there is a vast difference in the ATM capabilities of states and service providers in the region, and historically many states have developed their own infrastructure plans tailored to their specific needs. Among other barriers to integration are uneven investment by states and the reliance by some states on outmoded practices, such as maintaining old-technology-based excessive aircraft separations when current surveillance technology enables closer spacing.

Asia Pacific nations agreed to adopt a coordinated approach to communications, navigation, surveillance and ATM at a meeting held in Japan in 2013, the speakers said.

Li said Hong Kong International Airport has implemented surveillance by automatic dependent surveillance-broadcast (ADS-B) on two routes, and will require that aircraft entering the flight information region be equipped for ADS-B by the end of the year. The special administrative region is also replacing its systems for ATM, ATM data management, aeronautical information management and air traffic services message-handling. Eight airports and 11 airlines from Hong Kong, China, Singapore and Thailand are participating in an air traffic flow management trial that enters a second phase in the first quarter this year.

“The Asia Pacific region will progressively achieve an integrated and collaborative environment,” with enhanced safety and flight-handling capability, Li assured.