One flight plan with two places called DVL stopped UK air traffic control's flight data

transcript

Three letters froze UK air traffic control's flight data. Because two places on Earth are both called DVL.

28 August 2023, 08:32. A Los Angeles to Paris flight plan arrives. The plan lists DVL. It means Devil's Lake, North Dakota. The UK system hunts for the exit point. It finds DVL. Deauville, France.

Now the flight leaves UK airspace before it enters. Impossible. So the system does what it was designed to do. It stops itself. The backup takes over. Same plan. Same code. Same stop.

About 20 seconds. Both copies down. On a busy hour, the system handles up to 800 plans. By hand? About 60.

But here's the catch. The plan never left the queue. It was only removed after processing finished. Which never happened. So every reconnect sent it again. And knocked the system down again.

08:32. Both systems down. 11:00. Flights across UK airspace are restricted. Four hours in, with the manufacturer, they move the plan to a paused queue. 18:03. All restrictions lifted. Over 700,000 passengers hit.

One bad message should be set aside. Not stop everything. Give your queue a dead-letter path. Your backup runs the same code.

Full story in the article.