At 9:30 pm on 16th May, 1943, only eight weeks after No. 617 Squadron had been formed, the first wave took off from RAF Scampton. The second and third waves soon followed.
THE FIRST WAVE:
At midnight eight of the nine Lancaster's in the first wave arrived over the Moehne Dam. The ninth, AJ-B, flown by Flight Lieutenant Astell, had crashed near Dorsten after being hit by flak.
Gibson, in AJ-G, opened that attack by accurately placing his weapon; but failed to breached the wall.
After waiting for the water to settle. Flight Lieutenant Hopgood in AJ-M, began his run in, but was hit by flak and released his weapon late, causing it to bounced over the dam wall and explode harmlessly. His aircraft crashed soon after; only two crew members survived.
Having seen that the the German gunners had now identified the target and means of attack. Gibson in an attempt to confuse the gunners, escorted Flight Lieutenant Martin, in AJ-P, into the target. Martins' run however, was not accurate and his weapon exploded short of the wall.
Squadron Leader Young, in AJ-A, was next to make his run. Escorted by both Gibson and Martin, he managed to accurately place his weapon; but again the explosion failed to generate a breach.
Flight Lieutenant Maltby, in AJ-J, who like the remaining members of the first wave, had been circling the area waiting for his turn. He accurately placed his weapon with the aid of an escorted run. The explosion, proved too much for the Moehnes' wall, which was finally breached.
With only three "Upkeep's" remaining, Gibson ordered these aircraft to follow him to attack the Eder Dam. While the others began their return to base. With the exception of Squadron Leader Young, who was shot down by the coastal defences over Holland with all crew members killed. All returned safely to Scampton.
Arriving over the Eder. The target was found to be undefended and so the attack runs were made unescorted and without interference from flak.
Flight Lieutenant Shannon, in AJ-L, opened the attack and after several dummy runs, successfully placed his weapon. As the water settled a slight breach was noticeable, but was not sufficient to cause the dam to fail.
As was the case with Shannon's attack; Squadron Leader Maudsley, in AJ-Z, made several dummy attacks before releasing his weapon. His timing however was off and the late release of the weapon caused it to strike the parapet and explode on impact at almost the same time as his aircraft passed over head. Maudsley's aircraft was seriously damaged by the blast and it is reported that he may have actually received earlier damage to his aircraft by flak during the flight to the target. Once he had regained control, he immediately set course for Scampton. He would be shot down by light flak east of Emmerich, there were no survivors.
Pilot Officer Knight, in AJ-N, who carried the last of the first waves "Upkeep's". Accurately placed his weapon and the already weakened wall was breached.