Shortly before D-Day, he was asked to draw up a plan of attack to neutralize the Merville artillery battery. Legend has it that he voluntarily had himself locked in a room containing an exact model of the German position. A few hours later his plan was complete, using all his tactical skills, Otway put together an incredibly complex plan with tight timing. Unfortunately on the night of the landing all did not go according to plan. Most of the 750 men who had jumped were totally dispersed in the marais de Varaville, and the gliders carrying heavy and mine-clearing equipment were missing. Gathering just 150 soldiers he launched an assault on the battery and managed to silence the German guns, only to face two counter-attacks from a regiment of the 21st Panzer Division. Seriously wounded by a shell burst from friendly fire two days later, he was transferred to a Cardiff military hospital, where doctors declared him unfit to return to the front line.