In an unexpected turn of events, Indira Gandhi International Airport (IGIA), New Delhi — India’s busiest and most advanced aviation hub — faced a major air traffic control (ATC) system failure on November 7, 2025.
The glitch caused significant flight delays and disruptions, affecting hundreds of domestic and international passengers.
For a system that handles more than 1,500 flights daily, even a few minutes of malfunction can create ripples across the nation’s aviation network.
The Timeline of Events
- Early Morning, November 7, 2025:
The day began like any other at Delhi’s busy airport. However, by mid-morning, reports began to surface of widespread delays and flight disruptions. - Around 9:30 AM:
The Automatic Message Switching System (AMSS) — a core part of the ATC automation setup — experienced a technical fault.
This system is responsible for automatically processing and transmitting flight plans and communication data between different control units. - Transition to Manual Mode:
When the system failed, air traffic controllers had to switch to manual operations — entering flight details and clearances by hand.
Though a backup process exists for such emergencies, manual coordination significantly reduces efficiency and increases workload. - By Noon:
As more flights queued for departure and arrival, the delays grew to nearly an hour on average, with over 100 flights affected initially, later increasing to more than 400 as the day progressed.
Understanding the ATC System and the Failure
To grasp the scale of the disruption, it’s important to understand how the ATC system works:
- Automatic Message Switching System (AMSS): Handles flight plan messages, route data, and coordination between control units.
- Radar and Communication Systems: Track aircraft and maintain communication with pilots.
- Flight Data Processing System (FDPS): Converts raw flight data into usable information for controllers.
During the incident:
- The AMSS malfunctioned, stopping automatic data exchange.
- Controllers could still track aircraft and communicate with pilots, but data automation was halted.
- Manual flight coordination drastically slowed the process, leading to massive ground and air delays.
Immediate Impact on Operations
The Delhi airport operates almost one flight per minute during peak hours, making it highly dependent on automation. The glitch triggered a chain reaction of disruptions:
- Flight Delays
- Over 100 flights were delayed in the first few hours.
- By mid-day, more than 300–400 flights faced ripple delays across multiple airports connected to Delhi.
- Passenger Inconvenience
- Passengers experienced long waiting hours, crowded terminals, and frequent gate changes.
- Airlines like IndiGo, Air India, and Vistara issued public advisories requesting passengers to check flight statuses before heading to the airport.
- Airline Communication
- Airlines actively used social media to update passengers.
For example, IndiGo tweeted:
“Due to a technical glitch in Delhi ATC systems, our flights are experiencing delays. We regret the inconvenience.”
- Air Traffic Congestion
- The manual process slowed departure clearances, creating a bottleneck on runways and airborne holding patterns for incoming aircraft.
Response by Authorities
The Airports Authority of India (AAI) and Delhi International Airport Limited (DIAL) responded swiftly to manage the crisis.
Key measures taken included:
- Deploying Technical Teams:
Specialists were called in immediately to identify and repair the software malfunction. - Manual Operation Activation:
Controllers shifted to manual flight-plan entry, a tested backup method used during automation failures. - Official Statement:
AAI issued a statement confirming:
“Flight operations at Delhi Airport are experiencing delays due to a technical issue in the Automatic Message Switching System. Controllers are processing flight plans manually. Technical teams are working to restore the system at the earliest.” - Coordination with Airlines:
Airport authorities coordinated closely with airlines to manage departure queues and gate assignments, minimizing passenger inconvenience where possible.
Passengers’ Reactions and On-Ground Situation
Many passengers took to social media platforms such as X (formerly Twitter) and Instagram to share their experiences:
- Complaints of being stuck on aircraft for over an hour before takeoff.
- Congested boarding gates and rescheduled flights.
- Appreciation for ground staff and ATC officials who continued to manage flights manually under intense pressure.
Despite the chaos, no safety concerns or mid-air emergencies were reported — a testament to the skill and discipline of the ATC personnel handling manual operations.
Current Status
As of the evening of November 7, 2025, most systems were gradually restored, and flight operations began returning to normal.
However, residual delays continued into the night due to the accumulated backlog.
Authorities have since ordered a technical review of all ATC automation components to prevent similar failures in the future.