According to a report released by France's civil aviation investigation authority, BEA, multiple doctors who treated the Germanwings co-pilot did not inform authorities of a resurgence in mental health issues due to strict regulations in Germany regarding medical nondisclosure, DW wrote.
The BEA said "no action could have been taken by the authorities or his employer to prevent him from flying," since Lubitz did not inform anyone of their recommendations.
Previous reports show that Lubitz suffered from severe mental depression and suicidal thoughts.
In a report published by German daily "Bild," the Germanwings co-pilot complained about loneliness and sleep trouble after moving to Bremen in 2008, where he started his pilot training with Lufthansa.
"Committing myself to psychiatric treatment, severe depression, [my] dream of becoming a pilot is as good as finished," Lubitz reportedly wrote in his journal.
Reiterating similar BEA findings from May 2015, investigators said that Lubitz committed a "voluntary, illegal act" when he "intentionally adjusted" the Airbus 320's altitude target, setting it close to zero to enact a collision with the ground.
"The initial information from the investigation shows that, during the cruise phase, the co-pilot was alone in the cockpit. He then intentionally modified the autopilot instruction to order the airplane to descend until it collided with the terrain," the report said.
"He did not open the cockpit door during the descent, despite requests for access made via the keypad, the cabin interphone and knocks on the door," the report added.
Lubitz's deliberate actions on March 24, 2015, led to Germanwings flight 9525 crashing into the ground near the French village of Le Vernet, killing all 150 people on board.
