More than 800 flights were delayed and several cancelled at Delhi’s Indira Gandhi International Airport on Friday after a technical failure in the Air Traffic Control (ATC) system brought operations to a standstill. The Airports Authority of India (AAI) confirmed that the issue, detected in the Automatic Message Switching System (AMSS), a critical component of the ATC network, has now been resolved. However, residual delays are expected as the system clears the operational backlog.
“The AMSS systems are up and functional now. Due to some backlogs, there may be delays in the normal functioning of automated operations, but the situation will be normal soon,” AAI said in a post on X.
What Is AMSS?
The Automatic Message Switching System (AMSS) is an IP-based communication platform that serves as the digital backbone of air traffic management. It automatically transmits thousands of flight plan details, weather updates, and operational messages between airlines, air traffic controllers, and other aviation stakeholders each day.
When the system went down on 6 November, ATC controllers had to manually process each arrival and departure, which drastically slowed operations and led to widespread flight delays across Delhi.
According to Financial Express, the AMSS facilitates real-time data transfer about aircraft movement both in the air and on the runway. In its absence, controllers must rely on manual coordination, writing down flight details, calculating aircraft separation, and using voice communication, which ensures safety but severely affects efficiency.
Ripple Effect Across Major Airports
The technical fault did not just impact Delhi. Flight operations at Mumbai’s Chhatrapati Shivaji Maharaj International Airport and Ahmedabad’s Sardar Vallabhbhai Patel International Airport were also affected, as per data from Flightradar24.
The AAI said that additional staff and engineers from the Electronics Corporation of India Limited (ECIL) and the Original Equipment Manufacturer (OEM) were deployed immediately to manually handle flight plans and restore normal operations.
Government Review And Corrective Measures
Following the incident, a review meeting was held under the Civil Aviation Secretary, with the AAI Chairman and other senior officials in attendance. Directions were issued to identify the cause of the failure and implement safeguards to prevent similar disruptions in the future.
AAI reiterated that flight safety was never compromised during the outage and that controllers worked “with utmost diligence” to maintain operational integrity.
“The technical issue in the AMSS, which caused delays in processing flight plan messages, has been addressed,” the authority said.
While normal operations have resumed, AAI officials noted that it may take some time before flight schedules across affected airports fully stabilise.
Why AMSS Is Crucial
The AMSS is one of the most important systems supporting India’s air traffic management infrastructure, used to process and relay data essential for safe and efficient flight operations. Its uninterrupted functioning is vital for managing India’s rapidly expanding airspace, which handles hundreds of aircraft movements every hour.
A temporary shutdown of the system can paralyse airport operations, as was witnessed in Delhi, the country’s busiest aviation hub, handling over 1,300 daily flights.
