New Delhi, Nov. 25 -- Days after a major system glitch left over 900 flights delayed at the Indira Gandhi International airport, the Airports Authority of India (AAI) is set to upgrade the computer systems at Delhi's Air Traffic Control (ATC) by January next year, a project that was originally slated for completion by mid-2026. An official privy to the development said that the new system - the Aeronautical Message Handling System (AMHS) - had already been installed at the Delhi ATC, and was currently in the process of being commissioned. It would be ready to use in two months, he added. In the meantime, air traffic controllers are being trained according to the requirements of the AMHS. "The training is currently ongoing," the official said. "The new system will operate parallelly with the existing system (Automatic Message Switching System) for the initial few days before fully taking over operations," the official added. The Automatic Message Switching System (AMSS) has two servers - the primary and backup. However, both servers rely on a common switch. The switch distributes real-time information to both the servers. "If the primary unit fails, the backup takes over, but both rely on the same switch," another official said. On November 6, however, both the main and backup server units collapsed due to a single point of failure. The airport was plunged into chaos with its air traffic communication suffering a system failure, disrupting close to 65% of all flights and leaving thousands of passengers stranded. Therefore, in the interim, the AAI has rushed in emergency hardware changes, including installation of new primary and secondary servers along with an entirely new switch. "Though the impact on flights was controlled within hours, our systems were fully recovered and secured last week by the Electronics Corporation of India Limited," the second official said, adding that "why the glitch occurred is being ascertained". "When the issue occurred, we initially didn't know whether the problem was with the switch or the servers. When the main server failed, operations shifted to the backup server, but full control could not be established," the official added. He added that stand-alone controls had to be reinstalled on the spot to restore the system. Officials informed that temporary safeguards were capable of preventing the kind of disruption triggered on November 6. The rebuilt configuration ensures that the backup can function in case the primary system faces another fault. Notably, glitches are not uncommon in computer systems, even in ATC infrastructure, but this was the first incident that took more than 24 hours to be resolved, raising questions on the nature of the failure. Union civil aviation minister Ram Mohan Naidu took stock of the ATC on November 7 and directed that a detailed analysis be undertaken. Naidu also instructed officials to plan for system advancements, including additional or fallback servers to strengthen air traffic control operations....