ATC Guild warned of automation gaps months before major Delhi airport glitch

A major systems failure at Delhi’s Indira Gandhi International Airport disrupted air traffic operations for several hours between Thursday evening and Friday, delaying over 500 flights and leading to the cancellation of nearly 100. 

The disruption stemmed from a crash in the Automatic Message Switching System (AMSS) — a critical platform that integrates radar feeds, processes flight data, and enables communication between air traffic control units. With the system down, controllers were forced to switch to manual coordination, triggering cascading delays. 

The Airports Authority of India (AAI) confirmed the failure and said preliminary checks pointed to software and power supply issues. The Directorate General of Civil Aviation (DGCA) and the Ministry of Civil Aviation (MoCA) have sought a detailed report on the incident from AAI and the Air Navigation Services team. 

The episode has reignited concerns over ageing air traffic infrastructure. In July 2025, the Air Traffic Controllers’ Guild had warned about “performance degradation” in automation systems, citing lags and slowness particularly at high-traffic airports like Delhi and Mumbai. The Guild had called for periodic upgrades aligned with global benchmarks such as Eurocontrol and the FAA. 

“India’s systems must align with global benchmarks such as Eurocontrol and the FAA, which emphasise predictive tools, AI-enabled conflict detection, and real-time data sharing,” the Guild wrote in its communication. 

Compounding challenges, the outage came as IGIA temporarily decommissioned the Instrument Landing System (ILS) for runway 10/28 during an upgrade to Category III standards. Pilots have since been relying on GPS-based Required Navigation Performance (RNP) systems. However, GPS spoofing around 60 nautical miles from IGIA has affected RNP accuracy, leading to diversions and congestion — though officials denied any connection to the November 7 outage. 

By November 8, Delhi Airport said operations had returned to normal. Meanwhile, Mumbai International Airport clarified that an earlier advisory on disruptions was issued in error, confirming normal operations at Chhatrapati Shivaji Maharaj International Airport.