at the time of delivery to the escadrilles of the aéronautique militaire , the ps-7, constructed in 1915, was already obsolete. their low speed made the slow and lumbering craft an easy target for enemy antiaircraft guns and fighters. re-equipping with the more powerful 265 hp renault engine could not sufficiently alleviate these shortcomings. the p.s.7 were therefore mainly used as a night bomber against long-range targets such as railraod stations and supply depots, as on 13./14. april 1917 against the railway stations in marl and crécy-sur-serre and on 2 may against a german airfield near saint-quentin.