A single jet pitched its nose down at 35,000 feet, and about 6,000 aircraft ended up needing a fix.
The jet was a JetBlue A320 flying from Cancún to Newark on October 30, 2025. It dropped in altitude without any command from the crew. The autopilot stayed engaged and recovered the aircraft, and the flight diverted to Tampa, where 15 passengers were treated for minor injuries, mostly whiplash and anxiety. Nobody was seriously hurt.
How a flipped bit can move a control surface
Airbus traced the event to the Elevator and Aileron Computer, known as ELAC, the unit that turns pilot inputs into movement of the control surfaces. The company’s investigation linked it to possible data corruption in software version L104 on certain ELAC B hardware when the unit is exposed to intense radiation.
Airbus spoke of “intense solar radiation.” Experts later noted that high-energy cosmic rays can do the same job, causing what engineers call single-event upsets, which are bit flips in electronic memory. No major solar proton event was confirmed on that exact date, but the vulnerability was real under specific high-radiation conditions.
The fix, and who felt it
On November 28, 2025, Airbus issued an Alert Operators Transmission recommending immediate action. The European Union Aviation Safety Agency and other regulators followed with emergency airworthiness directives. Operators had to apply the update, or in fewer cases hardware protection, before the next revenue flight.
For about two-thirds of the affected aircraft, the remedy was a reversion to an earlier software version, which typically took around two hours. A smaller group, estimated at 1,000 to 2,000 aircraft, needed hardware shielding or deeper work, and downtime stretched to 24 to 48 hours in some cases.
Roughly 11,300 A320-family aircraft were active at the time, so the action covered about half the fleet. The timing was poor. It landed on the busy holiday travel period, including the post-Thanksgiving weekend in the U.S.
American Airlines, the largest A320 operator with 486 aircraft, confirmed that 340 were affected and said it expected to finish most updates by November 30. It warned of “limited” delays on busy routes such as Dallas-Fort Worth to New York LaGuardia. Delta called its impact “minimal,” though a handful of flights, including Atlanta to Miami, were cancelled at first. JetBlue grounded part of its fleet and logged over 50 cancellations through early December. ANA in Japan cancelled around 65 flights on November 29. Azul in Brazil reported no impact because its software configuration was different.
By December 1, 2025, Reuters reported that operations were returning to normal faster than many had feared. There were no hull losses or fatalities.
