Airlines are racing to implement the required software update in order to return aircraft back into service and minimise disruption.

In a statement, the plane maker said: "Analysis of a recent event involving an A320 Family aircraft has revealed that intense solar radiation may corrupt data critical to the functioning of flight controls.

"Airbus has consequently identified a significant number of A320 Family aircraft currently in-service which may be impacted."

It is understood the incident that triggered today's software warning involved a JetBlue flight from Cancun, Mexico, to Newark on 30 October.

That flight was diverted to Florida's Tampa International Airport at around 2pm local time after it suffered a flight control issue and experienced a sharp loss of altitude which injured several passengers.

An Airbus spokesperson told Sky News the necessary software change would affect up to 6,000 planes.

The fix involves A320 aircraft reverting to an earlier software update, with planes unable to fly passengers until this has been completed, according to a bulletin to airlines.

Airbus stressed that for most of the affected aircraft, the required software update would only take 2-3 hours. However, some aircraft would need new hardware to be able to adopt the required software and those aircraft would be affected for longer.

Travel expert Simon Calder said the situation was "very concerning" but that he had full faith in the safety procedures of Airbus and airlines. He went on to say that "aviation remains extraordinarily safe".

However, he warned that customers may not be entitled to cash compensation if affected by delays, as the issue would be considered out of the control of airlines.

EasyJet, British Airways, Aer Lingus, Indigo, Lufthansa, American Airlines, Delta, Air New Zealand, Flynas and Wizz Air are all affected by the issue - although the severity of the impact varies depending on the carrier.

Gatwick Airport has said the software directive "may result in some disruption" and urged passengers to contact their airlines for more information.

Airbus told Sky News that it had proactively asked the European Union Aviation Safety Agency (EASA) to issue an air worthiness directive for the affected aircraft.

The issue is affecting the A319, A320 and A321 models. Both older and newer neo models are affected.

The company said the issue is only affecting A320s that are in service, not aircraft that are due to be delivered.

The UK Civil Aviation Authority said it is likely to mean some disruption and cancellation to flights.

Transport Secretary Heidi Alexander thanked aviation workers and said: "The good news is it seems the impact on UK airlines seems limited, with a smaller number of aircraft requiring more complex software and hardware changes."

She added that it is "heartening this issue has been identified and will be addressed so swiftly", saying that this demonstrated "the high aviation safety standards globally".

Read more:
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In a statement, easyJet said: "As we are expecting this to result in some disruption, we will inform customers directly about any changes to our flying programme tomorrow and will do all possible to minimise the impact.

We have commenced and already completed the software update on many aircraft which require them and continue to work closely with the safety authorities."

Colombian airline Avianca has announced that it will close ticket sales for 10 days due to the issue.

American Airlines said the Airbus software issue would impact 340 aircraft and it expects some operational delays due to a major software change requirement.

The airline added that it expects the vast majority of the updates to be completed by "today or tomorrow", and that they are "intently focused" on limiting cancellations.

Delta, another US airline, also expects the issue to affect its fleet - specifically, less that 50 A321neo aircraft.

Wizz Air said some of its flights over the weekend may be affected, while Air India said the issue could lead to delays.

Indigo, an Indian airline which operates over 150 A320s, said it was proactively completing mandated updates on the affected aircraft.

British Airways told Sky News that only three of its aircraft were affected and that the required fixes will be carried out overnight and are not expected to disrupt its operations.

Aer Lingus is in a similar position, with a limited number of aircraft impacted. The airline doesn't expect there to be significant operational disruption, but is taking "immediate steps to complete the required software installations".

Turkish Airlines is already returning eight A320 aircraft to service after completing the required actions.

Heathrow Airport is not currently expecting any disruption to its services.

In October, the Airbus A320 family broke a major milestone when it overtook Boeing's 737 to become the most-delivered jetliner in history.

It appears to be one of the biggest recalls Airbus has faced in its 55-year history and comes just weeks after the A320 surpassed the Boeing 737 as the most-produced aircraft.

The move was triggered by a recent incident involving an A320-family aircraft, which revealed that intense solar radiation may corrupt data critical to the functioning of flight controls.

Follow the latest updates on Airbus disruption

Industry sources said roughly two-thirds of the affected aircraft will face only short groundings as airlines roll back to an earlier software version.

However, hundreds of jets may also need hardware replacements, potentially leading to much longer delays.

At the time Airbus issued its notice to more than 350 operators, some 3,000 A320 aircraft were flying worldwide.

Here is how airlines are affected by the issue:

British Airways

British Airways told Sky News that only three of its aircraft were affected and the required fixes will be carried out overnight and are not expected to disrupt its operations.

American Airlines

The world's largest A320 operator, American Airlines, said some 340 of its 480 A320 aircraft would need the fix.

The airline said it mostly expected these to be completed by Saturday with about two hours required for each plane.

Delta Air Lines

Delta Air Lines said it will comply with the directive and expects any operational impact on its Airbus A320 family fleet to be limited.

Lufthansa

German carrier Lufthansa said it has been informed of potential software issues affecting its Airbus A320-family fleet.

The airline warned that a small number of flight cancellations or delays may occur over the weekend, and confirmed it is fully complying with all manufacturer and regulatory requirements, having already begun implementing the measures prescribed by Airbus.

Wizz Air

A Wizz Air spokesperson confirmed that some of the airline's aircraft are among those requiring a software update flagged by Airbus.

The airline has already scheduled the necessary maintenance, but some flights over the weekend may be affected.

EasyJet

EasyJet said that following the safety directive issued to airlines operating A320 aircraft, "we have commenced and already completed the software update on many aircraft that require it and continue to work closely with the safety authorities".

The airline added that it plans to operate flights normally on Saturday and asked customers to continue monitoring their flights.

Aer Lingus

Irish carrier Aer Lingus said it has a "limited number of aircraft impacted" and is taking "immediate steps" to deal with the problem.

Turkish Airlines

Turkish Airlines said eight A320 aircraft in its fleet will be safely returned to service after completing the required actions, and all operations continue safely and without interruption.

Avianca

Colombian airline Avianca said on Friday that a major Airbus A320 recall impacts over 70% of its fleet, leading to "significant" operational disruptions over the next 10 days.

The carrier also announced it had suspended ticket sales for travel through to 8 December.

Air India

Air India said it is aware of an Airbus directive affecting its in-service A320-family aircraft.

The airline warned that required software and hardware updates on part of its fleet could lead to longer turnaround times and delays to scheduled operations.

IndiGo

India's low-cost carrier IndiGo said it is proactively completing the required updates on its A320 aircraft and warned that some flights may experience slight schedule changes.

Air New Zealand

Air New Zealand said it is currently affected by a global software issue impacting its Airbus aircraft.

The airline warned that several flights may be disrupted, with a number of cancellations expected across the fleet.

Flynas

Saudi Arabian budget airline Flynas said software and technical recalibration will be carried out on part of its fleet, causing some schedule delays following the Airbus recall.

United Airlines

The US carrier confirmed it was not impacted by the Airbus announcement.

Azul Airlines

Brazil's Azul Airlines said that none of its A320 jets are affected by the Airbus recall.

The aircraft manufacturer is carrying out software updates for 6,000 of its jets - around half the global fleet - threatening travel disruption for airline passengers.

The UK's Civil Aviation Authority said it expects some disruptions to airlines and flights, with easyJet and Wizz Air saying they will take some planes briefly out of service to do the repairs.

But why have airlines been told to carry out a software update for the planes, and how is solar radiation involved?

Follow the latest updates on this story

What triggered the repair order?

It is understood the incident that triggered the unexpected repair order involved a JetBlue flight from Cancun, Mexico, to Newark, New Jersey, on 30 October.

The flight suffered a control problem and a sudden uncommanded drop in altitude, basically a sharp loss of height, which left 15 passengers with injuries and forced the flight to make an emergency landing in Tampa, Florida.

After investigating the incident, Airbus said "intense solar radiation" may corrupt data critical to the functioning of flight controls.

The issue is known as bit flip, where solar radiation can strike a computer's memory, changing its data from a 0 to a 1 and vice versa - a risk which also affects spacecraft.

Read more: Which airlines are affected by Airbus disruption?

'Very concerning' - but 'very low likelihood' of such an event

The situation was "very concerning", travel expert Simon Calder told Sky News presenter Gillian Joseph.

However, he said there was a "very low likelihood" of such an event happening, adding: "In aviation, nothing is taken for granted."

He said: "Aviation remains extraordinarily safe. And that is partly because as soon as a possible threat is identified, then action is taken immediately."

What is the fix?

The fix involves reverting to earlier software, but must be carried out before the planes can fly again, according to a bulletin to airlines.

Airbus said for most of the affected aircraft, the required update would only take between two to three hours.

However, some jets may need to have their hardware replaced to adopt the required software - a process which would take a longer time.

The Airbus bulletin traced the problem to a flight system called ELAC (Elevator and Aileron Computer), which sends commands from the pilot's side-stick to elevators at the rear of the plane, Reuters reported.

Those elevators control the aircraft's pitch or nose angle, determining which way it is flying.

The A320 was first launched in 1984 and is the main competitor to the Boeing 737 MAX, which was grounded worldwide between March 2019 and December 2020, as well as during January 2024, after fatal crashes in 2018 and 2019 caused by faulty flight-control software.

Andrii Yermak resigned on Friday, hours after anti-corruption officials raided his home amid a major corruption scandal that has shaken the country.

Two ministers have already been forced to resign.

Ukraine war latest: Kremlin says it's only negotiating with US

But Yermak is by far the most significant departure from Zelenskyy's inner circle since Russia launched its full-scale invasion almost four years ago.

The dramatic move could not have come at a worse time for Ukraine, which is under daily Russian bombardment as well as increased American pressure to strike a deal with Moscow to end the war.

At a time when he needs to be stronger than ever, Zelenskyy will instead cut a lonely figure without his towering chief of staff, who has been by his side since he ran for president in 2019 and has been a hugely influential confidant ever since the first Russian missiles targeted Kyiv on 24 February 2022.

Yermak, despite being an unelected figure, has wielded tremendous power, including over ministerial and military appointments and over who had access to the president.

He was also appointed lead negotiator in peace talks, most recently representing Ukraine in Geneva alongside the US secretary of state Marco Rubio.

But critics have long been wary about his elevated wartime status, with Yermak effectively the second most powerful person in the country after Zelenskyy.

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It meant questions were immediately raised about what he may or may not have known when it emerged earlier this month that Ukraine's two main anti-corruption agencies had uncovered a plot to control contracts at the state atomic energy agency worth around $100m (£76m) in kickbacks and laundered money.

It is not yet clear what investigators were looking for when they raided Yermak's home, and he has said he was cooperating fully. He has not been charged with any crime or named as a suspect.

However, anti-corruption activists were quick to demand he leave his job or else risk tarnishing Zelenskyy's reputation in the scandal as well.

The US president alleged Mr Biden was "not involved" in signing the orders and claimed "the radical left lunatics circling Biden around the beautiful Resolute Desk in the Oval Office took the presidency away from him". He did not provide any evidence for his claims.

An autopen is a device which reproduces a person's signature, allowing them to repeatedly sign documents without having to do so by hand each time.

In a post on his Truth Social platform, he said: "Any document signed by Sleepy Joe Biden with the Autopen, which was approximately 92% of them, is hereby terminated, and of no further force or effect.

"The Autopen is not allowed to be used if approval is not specifically given by the President of the United States."

He added: "I am hereby cancelling all Executive Orders, and anything else that was not directly signed by Crooked Joe Biden, because the people who operated the Autopen did so illegally.

"Joe Biden was not involved in the Autopen process and, if he says he was, he will be brought up on charges of perjury."

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Mr Trump has repeatedly claimed Mr Biden was not mentally capable by the end of his term and his staff made decisions on his behalf, using an autopen to sign them off without his knowledge.

Mr Trump has not provided any evidence for his claims, while Mr Biden and his former aides have denied they made decisions on his behalf.

In June, Mr Biden said: "Let me be clear: I made the decisions during my presidency.

"I made the decisions about the pardons, executive orders, legislation, and proclamations. Any suggestion that I didn't is ridiculous and false."

Mr Trump has also used an autopen, but claimed he only used it "for very unimportant papers".

Earlier this year, Mr Trump replaced a portrait of Mr Biden in the Oval Office with a picture of an autopen signing the former president's name.