Delhi ATC Glitch Eases, Residual Delays Persist

Published on Nov 9, 2025, 12:31 pm CST

5 min read

Key points

Delhi's ATC messaging fault began November 6 and was restored by late November 7
Authorities ordered a 90 day upgrade, including redundancy and migration to AMHS
More than 600 delays and at least 46 cancellations were recorded at the peak
Residual knock ons persisted into Saturday, with average waits still elevated
Travelers should verify departures at Delhi, Mumbai, Bengaluru, and Ahmedabad

Impact

Plan Buffers: Build extra connection time on flights touching Delhi through early week
Verify Departures: Recheck flight status the night before and again three hours before departure
Prefer Morning Banks: Move to earlier departures where seats are open to reduce compounding delays
Watch Advisories: Monitor airline advisories and airport notices for rolling gate or time changes
Contingency Options: If a misconnect looms, ask for protected reroutes via alternate hubs in India

A failure in Delhi's air traffic control messaging backbone on Thursday afternoon, November 6, forced manual workarounds and triggered widespread delays into Friday, November 7. Authorities say the system was restored by late Friday and operations moved back to automatic mode on Saturday, November 8. India's government has now ordered a ninety day upgrade with added redundancy, which should reduce the risk of a repeat disruption. Travelers should still plan for residual ripples on trunk routes and verify connections before heading to the airport.

Indira Gandhi International Airport, New Delhi, India

What failed, and when. The Airports Authority of India reported a fault in the Automatic Message Switching System on the afternoon of November 6. That system handles flight plan messaging for controllers and adjacent systems, so even a partial outage quickly slows departures. Controllers shifted to manual processing to keep movements safe while technical teams worked toward restoration. By Friday evening, officials said the system was back, and by Saturday, the airport operator reported normal operations.

The scale of the disruption. Live tracking estimates and local reporting captured the surge in delays. Indian Express and other outlets tallied more than 600 delayed flights and at least 46 cancellations during the peak period, while some snapshots placed the delay count higher as Friday wore on. Average departure waits ranged from about 30 minutes to well over an hour at various points on Friday, then eased on Saturday as throughput improved. International carriers also absorbed significant holds while departure sequencing and flight plan flows normalized.

Knock ons across the network. Delhi anchors many domestic banks, so Friday's queues propagated into Saturday rotations at Mumbai, Bengaluru, and Ahmedabad, with scattered holds as aircraft and crews cycled back into position. Officials and the airport operator said normalcy was returning, however travelers still faced pockets of delay while backlogs cleared. Expect lingering schedule friction at the edges of the bank structure, especially on shorter sectors that turn quickly.

Latest developments

Upgrade mandate and milestones. Civil Aviation Minister K. Rammohan Naidu inspected the tower and directed a comprehensive upgrade within ninety days. The mandate includes adding backup servers and migrating from the older AMSS platform toward the Air Traffic Services Message Handling System standard, plus a root cause analysis and strengthened redundancy. Regulators asked for detailed reports to prevent recurrence. This is a meaningful systems step that should harden Delhi's messaging path against single point failures.

Status as of Sunday, November 9. Authorities and the airport operator say operations are normal, with the messaging flow back in automatic mode. That said, residual delays can linger where aircraft and crews remain out of position, particularly on high volume domestic corridors. Travelers booked through Delhi should plan conservative connections through Monday and keep a close watch on day of departure updates.

Analysis

Why this fault mattered. The messaging switch routes flight plan and related ATS messages between systems. When it fails, controllers can still move traffic, but with manual steps that slow releases and re clearances. The effect is similar to a lane closure on a busy expressway, the road still moves, but throughput drops and queues build. Even after restoration, airlines need time to reposition crews and frames, which is why knock ons can persist into the next day.

Background, how these systems fit together. AMSS and its successors sit alongside surveillance, automation, and tower tools and provide the plumbing for plan messages, departures, and coordination with adjacent units. Many countries, including India, have been migrating to AMHS, which supports modern message formats and better redundancy. India's order to complete defined upgrades in ninety days aligns with that global direction, and the added backup capacity should reduce the chance that one switch failure slows an entire hub.

Practical choices for travelers. If you are connecting, avoid tight turnarounds and prefer morning departures while backlogs clear. Recheck your flight the night before and again three hours before departure, since gate and time changes tend to cluster in recovery windows. If you see a misconnect building, ask your airline for a protected reroute via another domestic hub, for example Mumbai or Bengaluru, or for a same day change to an earlier flight where inventory allows. Keep an eye on airline advisories for fee waivers or flexible policies issued during the recovery. These steps trade a little lead time for a much higher chance of making the trip without last minute stress.

Final thoughts

Delhi's ATC messaging fault is fixed, and a ninety day upgrade is on the way. That is the right technical path, and it should lower risk in future peaks. In the near term, treat Delhi and its trunk connections as still clearing a residual queue, verify departures, and allow buffers until rotations fully stabilize.