About 90 Jetstar flights have been cancelled, and others have been delayed across Australia today due to a global recall of Airbus A320 planes for urgent software repairs.
This morning, Airbus ordered immediate repairs to 6,000 of its A320 family of jets, more than half the global fleet.
The recall has sparked disruptions across the globe, with aircraft engineers working to revert impacted planes to earlier software before they can fly again.
Jetstar's chief pilot, Tyrone Simes, said the carrier had 85 A320s in its fleet, but only 34 had been identified as having the software "anomaly".
He could not say how many customers had been affected by the disruption to flights, but said it would "certainly be into the thousands".
"We've got about 90 flights affected, and of course that's just Jetstar," he said.
"It is a worldwide issue, so there are many thousands of customers right across the world with different airlines affected."
Mr Simes said it was "difficult" to say how long the Jetstar disruptions would last, but said most repairs could be completed today.
He said each impacted plane would be grounded for two to three hours while engineers carried out the software fix.
"We're hoping to get it all done today and expecting the potential for some minor disruption tomorrow," Mr Simes said.
Impacted A320 planes that are not at airports with the necessary engineering support may be grounded longer.
Mr Simes said most of Jetstar's impacted aircraft were on Australia's east coast.
Qantas also has A320s in its fleet, but a spokesperson said none of its services had been impacted.
Virgin Australia operates four A320s for regional services in Western Australia, but a spokesperson said it "did not anticipate any impact" to its customers.
In a statement, Sydney Airport said the global software outage was causing delays for some domestic Jetstar services operating from Sydney.
"We're supporting Jetstar as they work to resolve the issue, and strongly advise all Jetstar customers to check their flight status with the airline before travelling to the airport," it said.
"All other airlines and flights at Sydney Airport are operating as normal and are unaffected."
There was chaos at Melbourne Airport on Saturday morning with many travellers arriving to find their flights cancelled.
Three Jetstar flights scheduled from Adelaide to the Gold Coast, Sydney and Cairns have also been cancelled.
Sidney Dekker, a Griffith University professor and former pilot, said the software fix would be "fairly simple" and required impacted planes to be grounded for about two hours.
"But then you also need the right expertise when the airplane is in the hangar to do the software update, and that's a little bit of a crunch," Dr Dekker told ABC News Breakfast.
"We've had this problem in Australia for a while — not enough aviation maintenance engineers to go around.
"Worldwide, it will reverberate for a couple of weeks before it settles. It will cause a lot of disruptions."
The Civil Aviation Safety Authority told the ABC it was aware of the issue "affecting the A320 family of aircraft globally".
"All aircraft that are affected will need to be checked in accordance with advice issued by Airbus and the European Union Aviation Safety Agency," a spokesperson said.
"We are in contact with major airlines and confident they are acting quickly to minimise disruptions and ensure aircraft can be returned to service safely."
Recall linked to flight-control software issue
About two-thirds of the affected aircraft worldwide will be briefly grounded, industry sources have told Reuters, while more than 1,000 may be grounded longer due to hardware changes.
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 have told Reuters that the incident that triggered the unexpected repairs involved a JetBlue flight from Cancun, Mexico, to Newark, New Jersey, on October 30.
Several passengers were hurt following a sharp loss of altitude, and the flight had to make an emergency landing at Tampa, Florida.
The setback appears to be among the largest recalls affecting Airbus in its 55-year history and comes weeks after the A320 overtook the Boeing 737 as the most-delivered model.
Some 3,000 A320-family jets were in the air worldwide shortly after Airbus's announcement on Saturday morning.
The world's largest A320 operator, American Airlines, said some 340 of its 480 A320 aircraft would need the fix.
It said it mostly expected repairs to be completed within a day, with about two hours required for each plane.
Other airlines said they would take planes briefly out of service to do the repairs, including Germany's Lufthansa, India's IndiGo, and UK-based easyJet.
Colombian carrier Avianca said the recall affected more than 70 per cent of its fleet, around 100 jets, causing significant disruption over the next 10 days and prompting the airline to close ticket sales for travel dates through December 8.
ANA Holdings, Japan's biggest airline, said it cancelled 65 flights on Saturday after the Airbus A320 recall.
India's aviation regulator has told airlines not to fly the Airbus A320 aircraft until modifications are carried out.
There are around 11,300 A320-family jets in operation, including 6,440 of the core A320 model, which first flew in 1987.
Four of the world's 10 biggest A320-family operators are major US airlines: American Airlines, Delta Air Lines, JetBlue and United Airlines.
Launched in 1984, the A320 was the first mainstream jetliner to introduce fly-by-wire computer controls.
It competes with the Boeing 737 MAX, which suffered a lengthy worldwide grounding after fatal crashes in 2018 and 2019, when faulty flight-control software pushed the planes' noses down.
The Airbus bulletin seen by Reuters 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. These, in turn, control the aircraft's pitch or nose angle.
The computer's manufacturer, France's Thales, said in response to a Reuters query that the computer complies with Airbus specifications and the functionality in question is supported by software that is not under Thales' responsibility.
ABC/Reuters
