In the course of the investigation into the crisis pilot, the former chief test pilot of the machine was indicted.

He is accused of having given wrong and incomplete information to the US authorities about the assistance system, which played a central role in two crashes of the plane. Therefore, airlines and their pilots were not informed about the functionality of the software, according to the ORF. When it was approved in 2017, Forkner was the direct contact between the aircraft manufacturer and the US FAA. According to documents released in early 2020, he had bragged about being able to deceive his FAA colleagues in order to obtain certification for the MCAS stabilization system specially developed for the Boeing 737 Max.

The system, called MCAS, was designed to help the pilots of the 737 Max keep the aircraft in the correct position. It became necessary because the aircraft got bigger engines - and in some cases this allowed the nose of the aircraft to go up. The software should then take countermeasures and make slight corrections. But as it turned out, MCAS could intervene in other situations and steer the machine downwards. In the two crashes in Indonesia in 2018 and in Ethiopia in 2019, pilots were not prepared for them, a total of 346 people died.

In both cases, the MCAS had submitted incorrect data. In March 2019, a global flight ban was imposed on the previous bestseller from Boeing, which was only lifted at the end of 2020 after a revision of the system.