European Union authorities were looking into German airline safety procedures on "a number of issues" well ahead of the March 24 Germanwings crash after a standard inspection by its aviation safety agency questioned some procedures.

An EU Commission official, who asked not be named because of the sensitivity of the situation, said Wednesday the issues included health checks of pilots but could not elaborate.

The official said that already in November EU authorities "had asked for clarification to make sure all airlines actively observe rules."

Germanwings co-pilot Andreas Lubitz had suffered from depression before he locked his captain out of the cockpit and deliberately flew the Airbus A320 into a French mountainside during the flight from Barcelona to Duesseldorf. All 150 people on board were killed.