Black Box (French: Boîte noire) is a 2021 French-Belgian mystery thriller film directed by Yann Gozlan. It is a co-production between France and Belgium. The film stars Pierre Niney as a talented young black box analyst at the Bureau of Enquiry and Analysis for Civil Aviation Safety who is tasked with investigating a mysterious fatal plane crash.^[2]

The film had its world premiere at the Alliance Française French Film Festival on 5 March 2021. It was theatrically released in France and Belgium on 8 September 2021. It received five nominations at the 47th César Awards.

On route from Dubai to Paris, a European Airlines Atrian 800 crashes over the French Alps, killing all 300 passengers and sixteen crew members. There is no obvious explanation for the crash. Mathieu Vasseur, a technician with BEA (the French agency charged with investigating aviation accidents) is given the task of analysing the cockpit voice recorder.

Mathieu attends a social event, where he meets an old friend, Xavier Renaud, who now runs Pegase Security, a firm which develops on-board communication systems for aircraft. The event is also attended by Mathieu's wife, Noémie Vasseur, who is shortly to leave her job at the aircraft regulatory body ASSA to take a senior role with Atrian.

On examining the voice recorder, Mathieu (who has ultra-sensitive hearing) identifies the sound of someone forcing his way into the cockpit shortly before the crash. This leads him to suspect a terrorist attack. Suspicion falls on an Egyptian passenger on the plane, whose computer is found to contain terrorist material. Mathieu announces his findings at a hastily-called press conference.

Mathieu's immediate boss, Victor Pollock, goes missing, so Philippe Rénier, the head of BEA, gives Mathieu the job of producing the final report into the crash. Mathieu notices inconsistencies in the voice recorder and a voicemail message recorded by a passenger just before the crash. As a result, he reconsiders his terrorist theory, but his doubts are dismissed by Rénier.

Mathieu drives to Pollock's house, which he finds empty. Footage from Pollock's dashcam shows that Pollock had a late-night roadside meeting with Renaud a few days before the crash. This leads Mathieu to suspect a cover-up. A European Airlines pilot tells Mathieu that the Atrian 800 had unresolved problems with the rudder's anti-stall system, but still received an air-worthiness certificate from ASSA. Mathieu surreptitiously downloads the relevant test flight data from Noémie's computer.

Noémie is suspended after her bosses at Atrian discover the loss of the data. She angrily confronts Mathieu, accusing him of ruining her career. Mathieu persuades Rénier to use the flight data to run simulations on the anti-stall system, but these fail to reveal any problems. As Mathieu becomes increasingly obsessed with the investigation, threatening his mental health, Rénier transfers him to other duties.

An investigative journalist, Caroline Delmas, tells Mathieu about a man named David Keller, a former Pegase employee who was arrested the previous year for attempting to hack an aircraft's communication systems. Looking at photos which passengers had uploaded to social media before the crash, Mathieu sees Keller on board the Atrian 800.

As Mathieu prepares to hand over his files to a colleague prior to his transfer, he comes across an audio recording of GPS coordinates. He traces these to a pond behind Pollock's house. Diving into the pond, he discovers the original voice recorder from the crashed plane. He returns to Pollock's house, where he uses equipment in the basement to analyse the recording. He thus discovers the truth about the crash (which is shown to us in a flashback). On board the doomed plane, Keller used a laptop to take control of the aircraft's systems, not because he wanted it to crash but to demonstrate faults in the Pegase systems. But the hack goes wrong, and neither he nor the pilots are able to regain control, thus causing the aircraft to come down.

At the end of the recording, Pollock appears in a video. He confesses to tampering with the voice recorder, having been blackmailed by Renaud over a long period into covering up faults in the Pegase systems. As he watches the video, Mathieu becomes aware of two men entering the basement, apparently looking for him. He flees the scene, but not before sending the recording and the video to Noémie. As he drives away at speed, he loses control of his car in a manner that suggests that the car's control systems have been hacked in a similar way to those of the crashed plane. He drives into a tree and is killed instantly.

When Xavier Renaud gives a presentation at the Paris Air Show, Noémie patches the video of Pollock's confession into the show's audio-visual system, where it is seen by an audience of industry leaders and journalists. As Noémie walks away from the presentation, police arrest Renaud.

The film had its world premiere at the 32nd Alliance Française French Film Festival in Australia on 5 March 2021.^[9] It was theatrically released in France by Studiocanal on 8 September 2021.^[10]