Origin of the problem, disturbances in the sky… Four questions on the immobilization of 6,000 Airbus A320s around the world

The recall, which affects the world’s best-selling plane, has caused flight delays and cancellations across the globe. The aircraft manufacturer Airbus announced on Friday, November 28, the immobilization of some 6,000 A320 planes, in order to urgently replace control software vulnerable to solar radiation. The group has notified its customers using this navigation software on its A320 model “to immediately stop the flights.”

“Disruptions are very limited” in Paris airports on Saturday morning, Agence Radio France learned from Paris Aéroports. On the Air France side, all passengers scheduled to travel with the company on Saturday “will arrive at their destination”, more “not necessarily at the time initially planned”, a company spokesperson reported to France Télévisions. Air France plans a “back to normal” Sunday, except for flights connecting Caribbean destinations. This massive immobilization raises several questions to which Franceinfo provides answers.

1 What is the technical problem causing the recall?

A fault was identified in the control software of an elevator-aileron computer (Elac) manufactured by Thales. As stated Release, these computers function as an intermediary between the controls at the cockpit and the elevators. Located at the rear of the aircraft, these small movable surfaces allow the plane to go up or down. “A pilot does not act directly on the control surfaces”explain to Parisian the former pilot Michel Polacco, aeronautics specialist. “Today, we act on computers to which we give orders and then, the computers analyze the situation and the position of the control surfaces, then modify it according to the objective sought by the pilot.”

An in-flight incident and its analysis “revealed that intense solar radiation could corrupt data essential to the operation of flight controls”Airbus reported on Friday in a press release. According to Michel Polacco, calculators are normally “extremely protected from the outside”, and located “in boxes” in various places on the device.

Thales, Airbus supplier, told AFP that it was not responsible for the problem. “The functionality in question is carried by software which is not Thales’ responsibility”he clarified.

2 How was this failure detected?

The incident whose analysis led to these conclusions took place on October 30 on a JetBlue flight between Cancun (Mexico) and Newark, near New York (United States). Over the Gulf of Mexico, the A320 plane carrying out this flight suddenly plunged downward, without any intervention from the crew. The pilots then began the descent phase then made an emergency landing in Tampa, Florida (United States).

According to the American Federal Aviation Administration, cited by the New York Times, the plane lost altitude after “encountered a flight control problem”. Fifteen to twenty people were taken to hospital after the emergency landing in Tampa, the Florida city’s firefighters reported.

3 What repairs will take place after this immobilization?

In its press release, Airbus ensures that it has “actively collaborated with the aeronautical authorities to request immediate preventive measures from operators, via a transmission alert to operators”. The objective, continues the aircraft manufacturer, is to “implement available software and/or hardware protections”in order to “to guarantee flight safety”.

The European Aviation Safety Agency reported a “vulnerability introduced by a software update in one of the on-board computers”. The organization issued an emergency airworthiness directive, which “requires the installation of a working Elac and prohibits the installation of an affected Elac”. Affected devices must therefore “replace or modify each Elac concerned with a working Elac”before any next flight.

Reverting to a previous version of the software should quickly resolve the problem in most cases, specifies the New York Times. An intervention could be carried out on Friday, during the night from Friday to Saturday or Saturday morning to “more than 5,000 devices”, according to Transport Minister Philippe Tabarot. On BFMTV, the minister reported that around a hundred Airbus A320s would be unavailable for a longer period of time, while faulty software was replaced. “We had mentioned the possibility of a thousand devices. It seems that we are now only talking about a hundred devices”he assured. Air France launched all updates to its A320s during the night from Friday to Saturday, a company spokesperson told France Télévisions.

4 What are the consequences for global air traffic?

Airbus recognized on Friday that “disturbances” would necessarily take place due to this immobilization and these repairs. Some companies are particularly affected: the Colombian company Avianca, for example, estimates that 70% of its fleet is affected. She glimpses “significant disruptions in the next ten days”and suspended ticket sales until Dec. 8, according to a statement.

In the Philippines, local companies Philippine Airlines and Cebu Pacific had to cancel more than 40 flights, and offered refunds and date changes to affected passengers. Indigo and Air India, two of India’s main airlines, have also warned of delays because of the immobilization. In the United States, United Airlines has identified six affected aircraft and said it expects “minor disruptions on a few flights”.

In France, 35 flights were canceled Friday evening from French airports, including around ten in Paris, Agence Radio France and France Télévisions learned from Paris Aéroport and Air France. SATURDAY, “disruptions are very limited” in Paris airports. Air France has revised its flight plans, in order to be able to transport all its passengers on Saturday, a company spokesperson told France Télévisions. Passengers who were supposed to fly on A320s were thus grouped on larger planes. “All our passengers for the day will arrive at their destination, not necessarily at the initially planned time”assured Air France.

The company plans to return to normal on Sunday, except for flights connecting Caribbean destinations, where planes require longer maintenance, according to this source. Traffic will thus remain disrupted between Cayenne (Guyana), Fort-de-France (Martinique), Pointe-à-Pitre (Guadeloupe), Santo Domingo (Dominican Republic) and Port-au-Prince (Haiti), specifies the company.