On 10 May 1940 the German "Wehrmacht" began "Fall Gelb" (Case Yellow); an invasion of Luxembourg, The Netherlands, Belgium and France. 3 Squadron were ordered to readiness that morning and flew to Merville, Nord in France. 3 and 79 Squadron were to form part of 63 Wing RAF. As they crossed the English Channel at 05:30 GMT, they were directed to a Ju 88 which they chased to the Dutch border without success and returned to England refuel. After landing the squadron was ordered to relocate to France. They were told the German Army had invaded France and the Low Countries. They reached Merville and found they were under-equipped in comparison to other squadrons that had been there since September 1939. The squadrons of the RAF Advanced Air Striking Force (AASF) possessed self-sealing fuel tanks, armoured protection for the pilot, and more powerful radio crystals.