CHENNAI: The Air Traffic Controllers’ Guild of India (ATC Guild) had cautioned aviation authorities months ago about “performance degradation” in key automation systems, particularly at high-traffic airports like Delhi and Mumbai, warning of potential safety and efficiency issues. The warning has resurfaced following a major system failure on November 7 that disrupted flight operations across the country.
According to reports, the glitch occurred in the Automatic Message Switching System (AMSS) — a critical platform that integrates radar feeds, flight data, and communication between air traffic control (ATC) units. The failure at Delhi’s Indira Gandhi International Airport forced controllers to switch to manual operations, triggering widespread delays and cancellations. More than 300 flights were delayed nationwide, with several airports including Mumbai, Ahmedabad, and Patna reporting cascading effects.
In a letter sent to Members of Parliament in July 2025, the ATC Guild had raised concerns about recurring “system slowness and lag” that compromised the real-time processing of flight data, especially during peak hours. The Guild had warned that such issues could undermine operational safety and the efficiency of airspace management if left unaddressed.
Airports Authority of India (AAI), which manages the automation network, confirmed the fault and said the system has since been restored. The Directorate General of Civil Aviation (DGCA) and the Ministry of Civil Aviation (MoCA) have sought a detailed report to determine the root cause of the failure.
Industry experts note that India’s aviation infrastructure has seen rapid traffic growth, but system upgrades have not kept pace. Both Delhi and Mumbai handle over 60–70 aircraft movements per hour during peak periods, leaving little margin for error when automation falters. “When systems lag or fail, controllers face higher workload and reduced reaction time, which can impact safety margins,” an aviation operations analyst said.
The incident has renewed focus on the resilience and redundancy of India’s ATC systems. Aviation safety specialists argue that automation platforms must be capable of “graceful degradation” — meaning they should continue to operate safely even in partial failure modes. The current episode, however, revealed heavy dependence on a single automation node at Delhi, leading to a nationwide ripple effect.
The ATC Guild has reiterated that its earlier warnings were intended to prompt urgent upgrades, including new-generation automation tools, real-time data integration, and backup systems aligned with global benchmarks such as those used by the US Federal Aviation Administration and EUROCONTROL.
A senior aviation industry consultant, seeking not to be identified, told The New Indian Express, that the episode underscores deeper issues — aging infrastructure, limited redundancy, and delays in procurement and system modernisation in the Indian civil aviation.
"The failure also raises questions about whether the authorities acted swiftly on the Guild’s concerns flagged months in advance," he said.
As operations return to normal, regulators are under pressure to ensure transparency in the investigation and accelerate the upgrade roadmap for air navigation systems.
Several other aviation experts quoted in news reports also stress the need for continuous monitoring of system performance, real-time alerts for lags, and faster fallback protocols to prevent a repeat of such large-scale disruption.
In the long term, the Delhi ATC incident is expected to serve as a wake-up call for India’s fast-expanding aviation ecosystem. With traffic projected to grow sharply over the next decade, ensuring reliable, scalable, and fail-safe automation will be critical to maintaining both safety and efficiency in the country’s skies, they say.