Mint Explainer: Why are thousands of Airbus jets grounded?

In India, 338 A320 aircraft operated by IndiGo (200) and the Air India group (138) were identified for this urgent software update.

What necessitated the software update?

The push for an immediate software update began after a JetBlue flight from Cancún to Newark on 30 October developed a serious mid-air issue. The aircraft reportedly suffered a sudden, uncommanded drop in altitude, forcing the crew to divert and make an emergency landing in Tampa, Florida.

Airbus traced the issue to a flight-control system called ELAC (Elevator and Aileron Computer), which sends commands from the pilot’s side-stick to the elevators on the tail, controlling the aircraft’s pitch or nose angle. Simply put, the ELAC acts as a messenger between the pilot’s joystick and the tail, telling the plane how to climb or descend.

Airbus said the incident revealed that intense solar radiation could corrupt data critical to the functioning of flight controls.

How does solar radiation impact flight controls?

According to SKYbrary Aviation, an electronic repository on flight operations and safety, solar radiation is the radiant energy and particles (photons, protons, electrons) emitted by the Sun, including visible light, ultraviolet rays, and infrared radiation. In aviation, solar radiation can generate additional atmospheric radiation capable of interfering with aircraft electronics—a phenomenon known as a “bit flip".

Such interference can corrupt data in sensitive flight control computers, potentially causing uncommanded manoeuvres and safety risks.

C.S. Randhawa, president of the Federation of Indian Pilots, noted that the severity of radiation directly correlates with the likelihood of electronic interference. Recent incidents, like the JetBlue flight that abruptly lost altitude, prompted urgent software updates and global recalls for thousands of Airbus jets. He commended Airbus for detecting the issue early and prioritizing flight safety.

What’s the fix?

The solution involves rolling the aircraft back to an earlier software version, which must be completed before the affected jets can return to service, according to Airbus’s bulletin to airlines.

For most planes, experts said the update takes only two to three hours. However, a small number of jets may also require hardware replacement to support the updated software, which could keep them grounded for longer.

Mark D. Martin, chief executive of aviation safety specialist Martin Consulting, explained that the update requires a dongle to be connected to the aircraft, a process that takes 2-4 hours. It can often be completed between flying schedules.

What's the impact on India?

In India, 338 Airbus A320-family aircraft require this software update, including 200 from IndiGo, 113 from Air India, and 25 from Air India Express. Across these three airlines, the total number of commercial A320-family aircraft in the country is 567, but not all need an upgrade.

On Saturday, the country's civil aviation regulator ordered airlines not to operate certain Airbus aircraft—A319, A320, and A321—until the urgent software or hardware updates mandated by Airbus were completed. The software upgrades are likely to be over by the weekend.

Only four Air India Express flights were cancelled as of 10am Saturday, according to the Directorate General of Civil Aviation (DGCA).

By 5pm, nearly 80% (270) of the affected fleet had received software upgrades, including 184 aircraft from IndiGo, 69 from Air India, and 17 from Air India Express. Two other carriers, Akasa Air and SpiceJet, operate Boeing aircraft, which are unaffected.

The three airlines will complete the upgrades by the end of the day, said the regulator’s evening report.

A spot check has been carried out on the fleet, and compliance has been verified, said a senior DGCA official on condition of anonymity.

Martin noted that the DGCA acted promptly in issuing procedures, ensuring a “safety first" approach. Both Air India and IndiGo stated they are complying with the DGCA directive, prioritizing passenger safety.