The German news agency dpa reported today that according to the new law, the airlines have to check pilots at the start of their shifts if there is a relevant indication that they may be under the influence of medication, alcohol or other psychoactive substances. There will also be random controls in the future.
On March 24, 2015, co-pilot Andreas Lubitz locked Germanwings Flight 9525's captain out of the cockpit and deliberately set the plane on a collision course with the mountain. All 150 people aboard, including Lubitz, were killed.