'Helen' was a US special forces operation to parachute a 15-man Office of Strategic Services operational group into the Ardèche area of German-occupied France to aid local resistance forces (28 August/mid-September 1944).
On 13 August the 'Helen' operational group took off on its original mission to block the Col de Larche in the Montgenèvre area of the Franco-Italian border, close to to that in which the 'Nancy' (ii) operational group was already on the ground. At this time the Germans most of the roads in the frontier region. When the Short Stirling adapted bomber in which the group was being transported reached the jump area, climatic conditions prevented the aeroplane’s descent below 2,000 ft (610 m). With the jump not permitted, the aeroplane returned to Algiers where, in the following two weeks, several operations were considered but had to be abandoned.
On 28 August the group departed the airfield at Maison Blanche near Algiers in three Boeing B-17 Flying Fortress adapted bombers for the 'Tandem' drop zone in the Ardèche. When the wrong signal was sent from the drop zone, the aircraft diverted to an alternate drop zone where there were no lights, and then returned to the primary field where Captain L. Vanoncini, the group’s commander, asked the pilot to allow the jump regardless of the signal. The drop had been successfully completed by 01.30, when the 15 men were warmly received by resistance and other OSS personnel in the area, before being taken to Devesset for food and accommodation.
On 31 August Vanoncini was one of a party led by Major A. T. Cox, the commander of the 'Lehigh' operational group, to an observation spot near Tournon, and here saw the large-scale movement of German forces to the north along the road on the western side of the Rhône river.
By 3 September the 'Helen' group had moved to Saint Etienne, where it was welcomed by an enthusiastic local population and joined a resistance group of 180 men under the skilled leadership of a Capitaine Georges, with which the Americans were to work. The group then moved to Saint Martin en Haut and on the same day led a column into Lyons, again to a tumultuously warm reception involving the considerable firing of small arms, including some from members of the Milice française Vichy French militia who had been left behind in the German and Vichy French withdrawal to the north. By a time late in the evening the city of Lyons appeared to become fairly safe.
On 8 September Cox sent Vanoncini to the Hautes Alpes to consider possible operations against the German forces moving up the Po river valley toward Turin. A reconnaissance was made, with Captain A. Lorbeer and 1st Lieutenant G. H. Weeks of the 'Nancy' (ii) and 'Peg' groups respectively, of areas between the Col de Saint Veran and the Po river valley, and revealed that the local resistance forces had little desire to oppose German movements. At one point Lorbeer’s group was surrounded, but Vanoncini’s group moved to maintain an avenue of escape for the US groups.
Orders were then received for the OSS groups to terminate operations in that area.