Thousands of Airbus aircraft were taken out of service for a software fix after it emerged that strong solar radiation might disrupt their flight-control computers.
Around 6,000 A320s were thought to be affected—half of the European company’s global fleet—but many were back in the air within hours of the update.
The UK aviation regulator said there would be “some disruption and flight cancellations,” although the impact on airports appeared to be limited.
Airbus said it discovered the problem after investigating an incident in October when a plane flying between the US and Mexico suddenly lost altitude.
A JetBlue Airways flight was forced to make an emergency landing in Florida after at least 15 people were injured. Along with the company’s best-selling A320, the vulnerability also affects the A318, A319, and A321 models.
It is believed that on around 5,100 Airbus planes, the problem can be fixed using a relatively simple software update that usually takes around three hours.
One airline, Wizz Air, confirmed that it had completed an overnight update on all of its affected A320 aircraft and that all flights would operate normally on Saturday.
However, at other airlines, there are 900 aircraft that are of the older version, and the onboard computers will need to be physically replaced, and they will not be allowed to carry passengers again until the work is completed.
How long it will take depends on the availability of replacement computers. Airbus said it acknowledged this would cause “disruption to passengers and customers” and apologized.
Aviation analyst Sally Gethin told BBC News that the situation was “very unusual” and said the disruption to passengers would depend on the “different approaches” airlines take to upgrading their software.
In the UK, disruption at airports has so far been limited. London’s Gatwick Airport reported “some disruption,” while Heathrow said it had no flights cancelled. Manchester Airport said it did not expect any major problems. British Airways and Air India are not expected to be heavily affected by the problem.
But Air France was hit by a minor disruption on Saturday morning, with many flights to and from Paris’ Charles de Gaulle airport delayed or cancelled.
Meanwhile, easyJet said it “expected some disruption” but later added that it had “started and completed a software update on many aircraft” and was planning to resume full service on Saturday.
In the US, the software problem emerged just before Thanksgiving weekend—one of the busiest travel periods of the year.
American Airlines said 340 of its planes were affected and expected “some operational delays,” but added that most of the updates would be completed on Friday or Saturday. Delta Air Lines said it expected the impact on its operations to be “limited.”
In Australia, budget airline Jetstar cancelled 90 flights after confirming a third of its fleet had been affected, with disruption expected to continue throughout the weekend, although most aircraft had already undergone the update.
Tim Johnson, policy director at the UK Civil Aviation Authority, said Airbus’s notice meant “unfortunately there is likely to be some disruption, delays, or cancellations in the coming days.”
He added that flying was still “one of the safest forms of transport” thanks to the rigorous maintenance programs implemented by airlines and described the mass grounding of flights as a “very rare occurrence.”
Transport Secretary Heidi Alexander said that “the impact on UK airlines appears to be limited,” adding, “It is pleasing that this issue has been identified and resolved so quickly, demonstrating the high standards of aviation safety globally.”
‘An action taken as a precaution’
The problem detected in the A320 aircraft is related to the computing software that calculates the plane’s altitude. Airbus found that at high altitudes, the intense radiation from the sun can occasionally distort the data.
This is what led to an incident in October in which an aircraft suddenly lost altitude—although the manufacturer stated that this was a first.
The European Union Aviation Safety Agency (EASA) has issued an Emergency Airworthiness Directive, requiring that all aircraft be corrected before carrying passengers again. They will be allowed to perform so-called “ferry flights” without passengers to reach maintenance facilities.
The A320 family is known as “fly-by-wire” aircraft. This means that there is no direct mechanical link between the controls in the cockpit and the parts of the aircraft that actually control flight; the pilot’s actions are processed by a computer.
