On 28 October 1918, Spa 154 was on patrol. Coiffard spotted German Fokker D.VIIs, and gave the signal to attack, which was seen only by his wingman. He and Second Lieutenant Condemine fought it out with the German patrol. While downing his 34th victim (a Fokker D.VII) he was critically wounded by two bullets; one hit him in the thigh and the other pierced his chest back to front passing through a lung. He flew 12 kilometers back to a perfect landing in friendly hands despite his wound, but died three hours later while receiving a blood transfusion in an ambulance transporting him to Berenicourt. The following day, he was posthumously made an Officer de la Légion d'honneur.