Flight operations at Delhi’s Indira Gandhi International Airport (IGIA) were thrown into disarray on Friday after a technical snag hit the Air Traffic Control (ATC) system, delaying more than 800 flights and stranding hundreds of passengers across terminals. Sources said the disruption, which began late Thursday, affected the Automatic Message Switching System (AMSS), a crucial communication network that feeds data to the Auto Track System (ATS), which generates flight plans for controllers. However, the AMSS system was restored by late Friday evening.
“Flight operations at Delhi Airport has been disrupted due to an ongoing technical issue with the Automatic Message Switching System (AMSS) that supports Air Traffic Control flight planning process. All airline operations at Delhi Airport are currently impacted. Concerned authorities are working on resolving the issue at the earliest,” the Delhi airport authorities said in a passenger advisory.
“Passengers are requested to follow updates from their airlines regarding revised schedules,” it added.
Much to the delight of passengers, the Airports Authority of India (AAI) said that the AMSS at the airport was restored by late Friday evening.
The glitch had affected the processing of flight plan messages, prompting manual operations to maintain air traffic safety.
AAI, along with ECIL officials, resolved the issue with OEM support. “Though minor delays may persist due to backlogs, automated operations are resuming, and normalcy is expected shortly,” an AAI statement said.
Earlier, with the automatic system down, air traffic controllers were forced to manually process flight plans, slowing operations and causing airspace congestion.
Aviation expert Captain Sharath Panicker later explained that the system failure meant flight plans had to be entered manually instead of being automatically interpreted by the software. “This manual process takes much longer and naturally leads to delays,” he said.
He added that the glitch also affected the Automatic Terminal Information System (ATIS), which integrates meteorological data from across the country. “Even the weather updates that pilots and controllers rely on now have to be fed in manually,” Panicker said, describing how the disruption compounded delays before take-off.
“Once the aircraft is in the air, there’s not much impact,” he noted, “but getting the aircraft airborne takes significantly longer under such conditions”. Panicker said restoration efforts were underway and expressed hope that the issue would be resolved by the end of the day.
A senior airport official confirmed the problem originated in the AMSS system, saying, “Controllers are preparing flight plans manually, which is taking significant time”.
IGIA, India’s busiest airport with over 1,500 flight movements daily, saw widespread disruption through the morning. Flight-tracking platform Flightradar24 showed average departure delays of 45–50 minutes by 9 am.
Following delays, airlines including IndiGo, SpiceJet, and Air India issued advisories alerting passengers to possible delays.
IndiGo posted on X that operations were being affected due to the technical issue, while SpiceJet said all departures and arrivals “might get affected” due to ATC congestion. Air India apologised for the “unforeseen disruption” and said its crew and ground staff were assisting passengers.
At the terminals, passengers faced long queues, repeated rescheduling, and extended waits inside aircraft. Many took to social media to complain of being stuck for hours without clarity from airlines.
By noon, technicians were still working to restore full functionality. Officials warned that clearing the backlog would take several hours, with ripple delays also reported at Mumbai, Lucknow, Jaipur, Chandigarh, and Amritsar airports.
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