Flights disrupted worldwide: What is ELAC, the Airbus System Behind the Chaos?

Air passengers across the globe faced issues after airlines cancelled and delayed flights over the weekend as a software problem affecting Airbus A320 aircraft prompted urgent updates.

Europe's Airbus said on Friday it was ordering immediate repairs to 6,000 of its widely used A320 family of jets in a sweeping recall affecting more than half the global fleet, threatening upheaval during the busiest travel weekend of the year in the United States and disruption worldwide.

In India, over 200 IndiGo, Air India and Air India Express planes were impcated.

As per the Airbus bulletin, the problem has been traced to a flight system called ELAC.

What is ELAC?

The flight system called ELAC (Elevator and Aileron Computer) is used for flight controls. ELAC sends commands from the pilot's side-stick to elevators at the rear. These in turn control the aircraft's pitch or nose angle.

What is the issue?

In aviation, intense solar radiation can interact adversely with flight's electronic systems, potentially disrupting navigation and flight control.

A recent incident involving an Airbus aircraft had revealed that solar flares may corrupt data critical to the functioning of flight controls.

Industry sources said the incident that triggered the unexpected repair action involved a JetBlue flight from Cancun, Mexico, to Newark, New Jersey, on October 30, in which several passengers were hurt following a sharp loss of altitude.

That A320 jet made an emergency landing at Tampa, Florida, after a flight control problem and a sudden uncommanded drop in altitude, prompting a Federal Aviation Administration investigation. JetBlue and the FAA had no comment on the recall.

The European Union Aviation Safety Agency (EASA) late on Friday issued an emergency directive making the fix mandatory.

As per media reports, investigators had found that the ELAC B hardware running software version L104 could be affected by solar flares. Failing to fix the issue might lead to the elevators moving unexpectedly, potentially pushing the aircraft beyond its structural limits.

How is the ELAC issue being fixed?

EASA has directed that the issue should be addressed before the next flight to be operated by the impacted aircraft by replacing or modifying the affected ELAC.

Airlines have been directed to either revert the flight-control software to a previous, stable version or replace the affected ELAC hardware with units already running the earlier software.

(With inputs from agencies)