Ing. J. Guillemain specialized in ambulance aircraft. JG.40 high-wing all-metal machine for 4 patients completed Villacoublay with Salmson 9Ab5 but re-engined 120-hp Lorraine 5Pc before flight 7 March 1931 for Service Technique. JG.42, for emergency 6 patients, flew 1932 with 175-hp Salmson (Bloch design chosen).