At the end of 1941, there were Z.501s in 15 of the 27 squadrons dedicated to naval reconnaissance. Strangely, the number of operational aircraft increased to an average of 100, rising six months later to 108 in 11 squadrons, probably due to the arrival of new aircraft.They were responsible, in collaboration with Italian ships, for the destruction of and damaged three other submarines. But their effectiveness was limited by their bombload of only four 50 kg (110 lb) or two 160 kg (352 lb) bombs.