One Piece of Software Cancelled 625 British Flights

At around one o’clock on Tuesday afternoon, the software that turns filed flight plans into departure clearances stopped working, and with it stopped most of British aviation. The fault sat in the flight-processing system operated by NATS, the body that manages UK airspace, and its effect was immediate and total: aircraft that were ready, fuelled and boarded simply could not be released. Some sat on Heathrow taxiways for more than five hours. Engineers implemented a fix at 16:40, close to four hours after the problem began, by which point the day’s schedule had already been destroyed.

Flightradar24 counted 625 cancellations to and from UK airports by 17:00 UTC. EasyJet alone accounted for 218 of them and British Airways for 132. Delays were spread far wider than the cancellations: about 281 of Gatwick’s roughly 850 scheduled flights ran late — close to a third of the airport’s entire day — while Manchester saw 249 of 650 delayed and Birmingham 101 of 300. Stansted, Luton, Edinburgh, Aberdeen and Glasgow all reported knock-on disruption. This was not a London problem that spilled outward; it was a national one, because the failed system serves the whole country.

The part that will hurt through the rest of the week is what happens after the fix. Restoring the software does not restore the operation. Aircraft finished Tuesday parked in the wrong cities, crews ran out of legal duty hours in airports they were not meant to overnight in, and airport slots that went unused cannot be recovered. Airlines spent Tuesday evening and Wednesday morning rebuilding schedules around equipment that is in the wrong place, which is why passengers who were nowhere near an airport on Tuesday may still find their Wednesday or Thursday flight cancelled or retimed.

There is a compensation angle worth knowing. UK261 treats air traffic control failures as extraordinary circumstances, which means airlines generally do not owe cash compensation for delays caused by them. What they do still owe is the duty of care — meals, refreshments, hotel accommodation where an overnight is required, and re-routing at the earliest opportunity, including on a competitor if that is what gets you there soonest. Passengers stuck in the backlog should ask for rebooking on another carrier explicitly rather than accepting the first seat their own airline offers three days out.

Sources: One Mile at a Time, IBTimes UK