Airbus said Friday that an examination of the JetBlue incident revealed that intense solar radiation may corrupt data critical to the functioning of flight controls on the A320 family of aircraft.

The FAA joined the European Union Aviation Safety Agency in requiring airlines to address the issue with a new software update. More than 500 U.S.-registered aircraft will be impacted.

The EU safety agency said it may cause “short-term disruption” to flight schedules. The problem was introduced by a software update to the plane’s onboard computers, according to the agency.

Airbus CEO Guillaume Faury apologized to customers after the required fix led to “significant logistical challenges and delays.”

“Our teams are working around the clock to support our operators and ensure these updates are deployed as swiftly as possible to get planes back in the sky and resume normal operations, with the safety assurance you expect from Airbus,” he wrote in a message posted on LinkedIn on Saturday.

Thanksgiving disruptions in US

In Japan, All Nippon Airways, which operates more than 30 planes, canceled 65 domestic flights for Saturday. Additional cancellations on Sunday were possible, it said.

The software change comes as U.S. passengers were beginning to head home from the Thanksgiving holiday, which is the busiest travel time in the country.

American Airlines has about 480 planes from the A320 family, of which 209 are affected. The fix should take about two hours for many aircraft and updates should be completed for the overwhelming majority on Friday, the airline said.

On Saturday, the airline said in a statement that only four planes still needed to be updated and that it “expects no further operational impact.”

Air India said on X that its engineers were working on the fix and completed the reset on more 40% of aircraft that need it. There were no cancellations, it said.

Delta said it expected the issue to affect less than 50 of its A321neo aircraft. United said six planes in its fleet are affected and it expects minor disruptions to a few flights. Hawaiian Airlines said it was unaffected.

Pope’s plane also needs a software fix

Pope Leo XIV is on his inaugural foreign trip, to Turkey and Lebanon, and is flying along with the papal delegation and press corps aboard an ITA Airways Airbus A320neo charter.

The Vatican spokesman, Matteo Bruni, said Saturday that ITA was working on the issue. He said the necessary component to update the aircraft was on its way to Istanbul along with the technician to install it. Leo was scheduled to fly from Istanbul, Turkey to Beirut, Lebanon on Sunday afternoon.

European flights return to normal

In France, Transport Minister Philippe Tabarot said the situation has stabilized as several software updates had already been installed. He told BFM-TV that the impact was limited in the country with an “almost complete return to normal in French airports.”

In the U.K., disruption also was minimal. British Airways, for example, said only three of its aircraft required the update, while EasyJet indicated there may be changes to its flying schedule as a result of the update, in which case passengers will be informed.

Germany’s Lufthansa said most software updates were completed during the night and on Saturday morning. No Lufthansa Group Airlines flights are expected to be canceled due to the current situation, but there may be minor delays over the weekend, it said.

Scandinavia’s SAS said its flights were operating as normal Saturday, after teams worked overnight to install the required software.

Mike Stengel, a partner with the aerospace industry management consulting firm AeroDynamic Advisory, said the fix could be addressed between flights or on overnight plane checks.

“Definitely not ideal for this to be happening on a very ubiquitous aircraft on a busy holiday weekend,” Stengel said from Ann Arbor, Michigan. “Although again the silver lining being that it only should take a few hours to update the software.”

At least 15 JetBlue passengers were injured and taken to the hospital after the Oct. 30 incident on board the flight from Cancun, Mexico, to Newark, New Jersey. The plane was diverted to Tampa, Florida.

Airbus, which is registered in the Netherlands but has its main headquarters in France, is one of the world’s biggest airplane manufacturers, alongside Boeing.

The A320 is the primary competitor to Boeing’s 737, Stengel said. Airbus updated its engine in the mid-2010s, and planes in this category are called A320neo, he said.

The A320 is the world’s bestselling single-aisle aircraft family, according to Airbus’ website.

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Associated Press writers Mari Yamaguchi in Tokyo, Jennifer Kelleher in Honolulu, Geir Moulson in Berlin, Samuel Petrequin, Pan Pylas in London and Nicole Winfield in Istanbul contributed to this report.