More than 400 flights at Indira Gandhi International Airport were hit by delays on Friday after a malfunction in the automatic message switching system (AMSS) slowed down air traffic control operations, leading to controllers processing flight plans manually.
The disruption affected both arrivals and departures at the country’s busiest airport, leading to long queues and delays across multiple airlines.
The Airports Authority of India (AAI) confirmed that the technical fault had affected data exchange systems used by air traffic controllers. In the absence of automatic processing, controllers shifted to manual handling of critical operational messages, a move that significantly increased workload and lengthened turnaround times.
The AMSS is a crucial digital platform that enables seamless communication between air traffic control units, airports and airlines. It automatically processes flight plans, route clearances and other operational updates. When this system goes offline, the staff must key in and relay flight data manually, which is far slower and more prone to bottlenecks. Officials said the issue first began on Thursday evening and persisted through the following day, leading to cumulative delays as schedules became increasingly misaligned.
AAI said technical teams were working to restore full functionality and urged passengers to keep track of flight updates through airline websites and airport channels. With more than 1,500 flights handled daily, even a partial disruption can quickly ripple into widespread operational challenges.
Airlines issued advisories through the day, asking passengers to arrive earlier and brace for delays. IndiGo acknowledged that services in Delhi and some airports in the northern region had been affected due to the ongoing AMSS issue and asked travellers to check flight status before leaving for the airport. The airline said its ground staff were deployed at counters and boarding gates to assist passengers.
Air India, too, advised passengers to monitor their schedules closely as some flights could continue to be delayed until systems stabilise. “We request guests to allow extra time and check flight status before departure,” the airline said. While efforts to restore the system continued late into the evening, officials said normal operations would resume progressively.