Some P-38 pilots scored multiple kills to become aces, while many others were shot down due to inexperience or tactical strictures. Overall, the P-38 suffered its highest losses in the Mediterranean Theater. The primary function of the P-38 in North Africa was to escort bombers, but the fighters also targeted transport aircraft, and later in the campaign, they were sometimes tasked with ground-attack missions. When tied to bomber-escort duties, the P-38 squadrons were vulnerable to attack from above by German fighters, who selected the most advantageous position and timing. The initial tactical doctrine of the American units was for the P-38s to fly near the bombers at all times rather than to defend aggressively or to fly ahead and clear the airspace for the bombers, and many American pilots were downed because of this limitation. Losses mounted, and all available P-38s in the UK were flown over to North Africa to restore squadron strength. After this painful experience, the American leadership changed tactics, and in February 1943, the P-38s were given free rein in their battles. The first German success against the P-38 was on 28 November 1942, when Bf 109 pilots of Jagdgeschwader 53 claimed seven Lightnings for no loss of their own. Further one-sided German victories were noted on several occasions through January 1943. The first P-38 pilots to achieve ace status were Virgil Smith of the 14th FG and Jack Illfrey of the 1st FG, both credited with five wins by 26 December. Smith got a sixth enemy aircraft on 28 December, but was killed two days later in a crash landing, likely after taking fire from Oberfeldwebel Herbert Rollwage of JG 53, who survived the war with at least 71 kills. This was Rollwage's first victory over a P-38, and his 35th claim at the time. The two squadrons of the 14th Fighter Group were reduced so badly in December 1942 that the 82nd FG was flown from the UK to North Africa to cover the shortage. The first kill by the 82nd was during a bomber-escort mission on 7 January 1943, when William J. "Dixie" Sloan broke formation and turned toward six attacking Bf 109s to shoot one of them down. Known for his maverick style, Sloan racked up 12 victories by July 1943. After another heavy toll in January 1943, 14th FG had to be withdrawn from the front to reorganize, with surviving pilots