Airbus said a recent incident involving an A320-family aircraft had revealed that solar flares may corrupt data critical to the functioning of flight controls.
Industry sources said the incident that triggered the unexpected repair action involved
a JetBlue flight from Cancun, Mexico, to Newark, New Jersey, on October 30, in which several passengers were hurt following a sharp loss of altitude.
That flight made an emergency landing at Tampa, Florida, after a flight control problem and a sudden uncommanded drop in altitude, prompting a Federal Aviation Administration investigation.
JetBlue and the FAA had no comment.
The European Union Aviation Safety Agency late on Friday issued an emergency directive mandating the fix, and the FAA was expected to follow suit.
'TWO HOUR REPAIR'
An Airbus spokesperson estimated the repairs would affect some 6,000 jets in total, mixed between several variants, confirming an earlier Reuters report.