My mother mentioned that in the later war years a single airplane regularly (daily, weekly?) conducted bombing raids on the local steel factory of Siegen-Geisweid, Germany. It was supposedly an RAF plane and came at night. Due to its persistence the locals tagged the plane "Eiserner Heinrich" (Iron Henry) Does anyone know whether these regular single plane bombing missions really existed? If so, who would plan and conduct them? Which units would fly those type of missions and what aircraft was used? Thanks.