Pilote américain engagé volontaire à la Légion étrangère.
Participe aux missions spéciales coordonnées du 23 septembre 1915.
Redécolle après avoir déposé son missionnaire. Réattérit pour prendre Mangeot, avec lequel il avait réalisé la mission, et dont l'appareil a été détruit à l'atterrissage. Son appareil capote dans cet ultime décollage. Ils sont faits prisonniers. S'évadent, sont repris et ne seront libérés qu'en décembre 1918
American volunteers in the french foreign legion, 1914-1917
"French aviators flew far behind the German lines, to observe and report what was going on there. Among them were two of the American Legionnaires of 1914, William Thaw and James Bach. The latter had the misfortune to become the first American to fall into the hands of the Germans, on September 23. Bach was sent on a special mission with a French pilot Sergeant Mangeot. Their task was to land two French soldiers, dressed as civilians, behind the enemy lines near Mézières, where an important railway bridge was to be blown up. The two aviators succeeded in landing their passengers, who hastened away with charges of high explosives. Bach then started off in his aeroplane, but, looking back saw that is comrade had smashed his aeroplane in attempting to take off over the rough ground. Without hesitating, although well aware of the risk he was running, Bach turned his machine, landed again, and picked up Mangeot. Trying to take off the second time, he ran into a tree, and wrecked his aeroplane. The men hid in the wood for a time, then tried to make their way back to the French lines. They were captured, however, and were court-martialed three times by the Germans on the charge of being spies. With the help of an able Berlin lawyer, they were acquitted and sent to a prison-camp, where Bach spent the remaining three years of the war. In 1918, James Bach returned from captivity in Germany a few weeks after the Armistice. Bach was decorated with the Médaille Militaire and the Croix de Guerre, his citation reading: Of American nationality, he enlisted in the Foreign Legion and accomplished valiantly his duty as an infantryman. Passed into the Aviation, he became in very little time an excellent military pilot, giving proof of intelligence, of courage, of sang-froid, and of skill. September 23, 1915, he solicited the honor of being designated for a perilous mission. He fulfilled it, and was made prisoner for having wished to save his comrade."