This article is more than 2 years old.

April 29, 2015 This article is more than 2 years old.

This post has been updated.

American Airlines flights experienced significant delays this evening after pilots’ iPads—which the airline uses to distribute flight plans and other information to the crew—abruptly crashed. ”Several dozen” flights were affected by the outage, according to a spokesperson for the airline.

An investigation by the airline traced the problem to an iPad app made by the Boeing subsidiary Jeppesen, which contains maps of various airport facilities. When a new version of a runway map for Ronald Reagan Washington National Airport was distributed, it conflicted with an older version of the map stored on some pilots’ iPads, an airline spokesman told Recode.

No flights were canceled, and pilots have been notified how to fix the bug, by deleting the app and re-installing it. Apple said it had confirmed that the iPads’ own hardware and operating system did not crash, and that the issue was with the Jeppesen app.

But when the glitch first surfaced, passengers expressed surprise and frustration at unexpected source of the delay.

“The pilot told us when they were getting ready to take off, the iPad screens went blank, both for the captain and copilot, so they didn’t have the flight plan,” Toni Jacaruso, a passenger on American flight #1654 from Dallas to Austin, told Quartz.

“The pilot came on and said that his first mate’s iPad powered down unexpectedly, and his had too, and that the entire 737 fleet on American had experienced the same behavior,” said passenger Philip McRell, who was also on flight #1654. “It seemed unprecedented and very unfamiliar to the pilots.”

Other passengers in New York and Chicago also said they were being affected by the outage.

The airline issued this message on Twitter in response to a stranded passenger:

American switched its pilots to an iPad-based “electronic flight bag” made by Jeppesen in 2013, replacing the heavy paper-based reference materials that pilots carried previously. American said the change would reduce the frequent injuries incurred by pilots from carrying heavy flight bags, and would also save time by making revisions electronically.

Jacaruso and McRell tweeted about their predicament, as did other passengers.