A French court is due to rule on Monday whether Airbus and Air France are guilty of manslaughter over the 2009 crash of Flight 447 en route from Rio to Paris, which killed 228 people and led to lasting changes in aircraft safety measures.
Acquittal is likely, in what would be a devastating defeat for victims’ families who fought for 13 years to see the case reach court.
The two-month trial left families wracked with anger and disappointment. Unusually, even state prosecutors argued for acquittal, saying that the proceedings did not produce enough proof of criminal wrongdoing by the companies.
Prosecutors laid the responsibility primarily with the pilots, who died in the crash.
Airbus lawyers also blamed pilot error, and Air France said the full reasons for the crash will never be known.
Airbus and Air France face potential fines of up to 225,000 euros (£199,000) each if convicted. While that is just a fraction of their annual revenues, a conviction for the aviation heavyweights could reverberate through the industry.
No-one risks prison, as only the companies are on trial.
The A330-200 plane disappeared from the radar in a storm over the Atlantic on June 1 2009, with 216 passengers and 12 crew members on board.
It took two years to find the aircraft and its black box recorders on the ocean floor, at depths of more than 13,000ft (around 4,000m).
The official investigation found that multiple factors contributed to the crash, including pilot error and the icing over of external sensors called pitot tubes.
An Associated Press investigation at the time found that Airbus had known since at least 2002 about problems with the type of pitot tubes used on the jet that crashed, but failed to replace them until after the crash.
Air France is accused of not having implemented training in the event of icing of the pitot probes despite the risks.
Airbus is accused of not doing enough to urgently inform airlines and their crews about faults with the pitots or to ensure training to mitigate the risk.
The crash had lasting impacts on the industry, leading to changes in regulations for airspeed sensors and in how pilots are trained.
The trial was fraught with emotion. Distraught families shouted down the chief executives of Airbus and Air France as the proceedings opened in October, crying out “Shame!” as they entered the witness box.
Dozens of people who lost loved ones stormed out of the court as the trial concluded with the prosecutors’ surprising call for acquittal.