 The first confirmed kill by 172 squadron came a month later, on 5 July, when a Wellington piloted by P/O Wiley B. Howell in 'H' for Harry, one of many Americans who had joined the RAF, sank "U-502" in the Bay of Biscay.As the invasion of France became nearer the squadron concentrated on operations over the western-end of the English Channel.Following the invasion of France the squadron moved to RAF Limavady in Northern Ireland to counter the U-boat threat in the North Atlantic.