He said the tragedy was compounded by the apparent senselessness of the co-pilot’s actions in bringing down the plane.
Mr Gauck said people across Germany, which lost 72 citizens, are still coming to grips with the March 24 crash. The second-biggest group of victims was from Spain, which lost 51 citizens.
Prosecutors have said co-pilot Andreas Lubitz deliberately crashed the plane into the French Alps on the way from Barcelona to Duesseldorf, killing all 150 on board. They are still trying to determine why.
“We really don’t know what was going through his head during those deciding seconds, in the deciding minutes,” Mr Gauck told the congregation that also included Chancellor Angela Merkel, ministers from Spain and France, and the heads of Germanwings and its parent airline, Lufthansa.
“But we do know that his relatives also lost on March 24 a person whom they loved.”