On 13 March 1943, during a visit by Adolf Hitler to Army Group Center Headquarters in Smolensk, Schlabrendorff smuggled a time bomb, disguised as bottles of cointreau, onto the aircraft which carried Hitler back to Germany. The bomb detonator failed to go off, however, most likely because of the cold in the aircraft luggage compartment. Schlabrendorff managed to retrieve the bomb the next day and elude detection.