Elsewhere in the formation, 21-year-old Thomas Therrien, a native of Brockton, Massachusetts, scoured the skies for enemy aircraft. Therrien was part of the 305th Bomb Group based at Chelveston and was a member of the crew led by pilot Neal Fisher. 

Located deep in the heart of Germany, the target was well beyond the range of escort fighters. Spitfires and P-47s equipped with drop tanks would escort the bombers halfway to the target, but from then on, the bombers would have to fend for themselves. Therrien gripped his waist gun as the Spitfires wagged their wings and headed for home, having reached the end of their range. 

Almost as soon as the escort aircraft left, Luftwaffe single-engine fighters swooped in on the bombers, firing head-on. The first wave was swiftly followed by an attack from Ju-88 fighters, firing 20cm rockets from outside of the defensive range of the B-17s. The bombers, now scattered, were easy prey for the marauding Luftwaffe, who launched continuous attacks all the way to the target. 

Once over Schweinfurt, flak took the place of the fighters, barraging the B-17s as they crossed over the city. Now on the bomb run, David Palmer struggled to keep “The Duchess” straight and level as flak burst around him. The bomber lurched as a shell ripped through engine number three, knocking it out of action. Finally, the mauled aircraft received the signal to drop its bomb load and turned for the long journey back to England, as enemy fighters continued to torment the battle-worn B-17s. 

Therrien’s B-17 was lagging dangerously behind the rest of the 305th formation as it made its way to the German border. In the belly of the bomber, Therrien began firing as the call of “Bogies!” blared out over the intercom, crimson tracers dancing across the sky. Cannon fire pierced through the thin aluminium of the B-17, knocking out the intercom system and wounding Thomas Therrien’s fellow waist gunner, Loren Fink. As the B-17 heaved and groaned under the barrage, the order to bail out was passed down the fuselage. Therrien helped Fink and the wounded radio operator out of the waist door before preparing to jump. At that moment the plane lurched under another torrent of bullets and Therrien was pushed back into the aircraft. Re-emerging at the door, he was struck by a 20mm shell, which killed him before he could jump. Four members of the crew died, while the remaining six were taken as Prisoners of War. Thomas Therrien is buried in the Ardennes American Cemetery in Belgium. 

The Schweinfurt Raid was lauded as a success by USAAF planners, but intelligence would show that its impact on German industry was minimal. In all, the Eighth Air Force lost sixty B-17s, with a further seventeen no longer airworthy. Worse still, 600 men had been killed, wounded, or missing in action, totaling almost 20 percent of those who took part in the mission. The raid has strategic implications far beyond the loss of men and machines. The danger of flying unescorted missions deep into enemy territory had been proven to be unsustainable, and for the remainder of 1943, USAAF planners would restrict raids to France, the European coastline, and the Ruhr Valley. “Black Thursday” signaled a turning point in Eighth Air Force doctrine and the flawed belief that a mass formation of bombers could defend itself against enemy fighters. It was an important lesson and one that was learned at the cost of men like Thomas Therrien, who were victims of attacks by enemy fighters.

For David Palmer, touching down at Polebrook brought an end to five months of combat flying. Speaking to his hometown newspaper on his return to the States, he called Schweinfurt the most memorable of his 25 missions, “It was plenty hot, and don’t let anyone tell you those German fighters aren’t good. They’re too darn good.”  Palmer was awarded the Distinguished Flying Cross for his action at Schweinfurt, but it was his lucky charm that he valued most, “I still have the five American dimes I’ve carried with me on every raid. I’m going to keep them for the rest of my life.”