Critical system restored at IGI Airport in Delhi; 500 flights hit by delays

Over 500 flights faced delays in Delhi after a key communications system malfunctioned, causing chaos and 46 cancellations. The system was restored by Saturday.

Cascading delays affected over 500 flights arriving or departing the national Capital on Saturday, a day after the country’s busiest airport was plunged into chaos when a critical communications system went offline.

Passengers outside the departure terminal at Indira Gandhi International (IGI) Airport in New Delhi on Friday. (Sanjeev Verma/HT Photo)

The Air Message Switching System — the digital backbone that feeds crucial flight plan data to controllers — was fully restored to automatic mode by Saturday afternoon, officials said, nearly 48 hours after the system stopped transmitting information automatically to controller screens on Thursday afternoon. The system was partly restored late on Friday.

The government said in a statement on Saturday that the technical glitch, which occurred on the afternoon of November 6 and continued into the morning of November 7, led to the cancellation of 46 flights. There were no flight cancellations on Saturday, the ministry said.

“It was around 7pm on Friday that we restored the system. However, it remained under observation for about two hours thereafter,” a senior ministry official said, asking not to be named.

Civil aviation minister Rammohan Naidu visited the airport around 10pm on Friday along with civil aviation secretary Samir Kumar Sinha, Airports Authority of India chairman Vipin Kumar and other senior officials to review the situation.

The minister returned to the air traffic control tower on Saturday evening to review normalised operations and appreciate the teams that worked overnight to resolve the glitch.

“While the system has been functioning smoothly since then, there are cascading delays, mostly in departing flights,” another official confirmed, adding that operations were expected to normalise by midnight Saturday.

The airport, which handles about 1,550 flights daily, saw around 65% of them delayed on Friday. Over 500 flights, mostly departures, continued to face delays on Saturday as the backlog worked through the system.

According to Flightradar24 data, departures were delayed by an average of 39 minutes, with 85% of flights affected till 10.30pm.

“From the onset, teams from the Airports Authority of India, Air Navigation Services and Electronics Corporation of India Limited worked round the clock to identify and rectify the issue,” the ministry said in a statement. “ECIL promptly deputed additional manpower to assist in the restoration process. During this period, ATC staff efficiently managed flight operations manually to ensure passenger safety and minimise inconvenience.”

The minister on Friday directed ECIL to deploy additional technical manpower to expedite restoration efforts. He also instructed that more air traffic control staff be deployed at Delhi Airport to support manual operations and ensure smooth handling of air traffic during the system downtime.

The government did not clarify on what caused the glitch in the first place or why no backups were in place.

The AAI set up a 24-hour crisis room that managed the situation with around 30 to 40 additional personnel working alongside the system’s original equipment manufacturer, an official said.

“It was not easy to keep operations going, but with the hard work of air traffic controllers, flights were managed manually and efficiently,” the official said. “There were delays in handling traffic, but in an airport as large as Delhi, it was a challenge to ensure that flight operations did not pause even briefly.”

An airport official said: “The minor delay had a multiplier effect and affected flight schedules, but the situation was managed efficiently. The air traffic controllers displayed the highest level of sincerity and patience.”

Naidu directed that a detailed root-cause analysis be undertaken to prevent a recurrence. He also instructed officials to plan for system advancements, including additional or fallback servers, to strengthen air traffic control operations.