Airbus A320 glitch: Why does the fleet need an urgent software update? | Explainer

New Delhi: An emergency airworthiness directive was issued by the European Union Safety Agency (EASA) on Friday, temprorarily grounding up to 6,000 Airbus A320 aircrafts globally to carry out urgent and critical software or hardware updates. "An Airbus A320 aeroplane recently experienced an uncommanded and limited pitch-down event. The autopilot remained engaged throughout the event, with a brief and limited loss of altitude, and the rest of the flight was uneventful," the EASA said in a statement.

The EASA further said that a malfunction of the affected Elevator Aileron Computer (ELAC) had been identified as the possible contributing factor by Airbus' preliminary technical assessment.

"This condition, if not corrected, could lead in the worst-case scenario to an uncommanded elevator movement that may result in exceeding the aircraft's structural capability," the European Union's safety agency further said.

What led to the software upgrade?

An A320 aircraft operated by JetBlue was travelling to Newark in the United States from Cancun in Mexico on October 30. Cruising at 35,000 feet, it faced a flight control issue due to a computer malfunction, which resulted in a sudden nose-down movement without any command from the pilot. It caused the flight to experience a harrowing but brief drop in altitude. The flight was safely diverted to Tampa. Investigators pointed to a glitch in the ELAC – a system that translates pilot inputs to the wings and tail.

Airbus evaluated the technical glitch and instructed its clients to take "immediate precautionary action."

The European aircraft maker also said that strong solar radiation can interfere with the ELAC’s newly updated software, messing up important data and potentially causing sudden movements that could put extra stress on the aircraft.

How the fix will be implemented

The type of upgrade depends on the A320 variant. Older aircraft will need their ELAC computer replaced, while newer ones only need a software update.

A source told AFP that updating the software on most aircraft will take only a few hours, but for around 1,000 planes, the work could take weeks.

Fixing the issue may cause flight delays, depending on where the aircraft are scheduled to fly.

Indian airlines directed to resolve the issue

The alert by the EASA prompted India's Directorate General of Civil Aviation (DGCA) to order Indian airlines to resolve the issue before operating the A320s in their fleet. Notably, the software upgrade impacts 200 Indigo aircraft. However, there were no delays. Out of the 200 affected aircraft, 143 have already received the software upgrade. 

The upgrade has affected 113 Air India aircraft and 25 India Express planes. Air India didn’t cancel any flights and has finished the software upgrade on 42 aircraft. Air India Express, however, faced delays on eight flights, and only four of its 25 affected aircraft have been upgraded.

The upgrade for all three airlines is expected to be finished by Sunday evening.