If it is completable, that's damned hard. I completed it with the RAF on the first try (103 missions (my longivity record), British troops walked on Berlin on 30th July 1944) but I never succeeded to complete it with the USAAF.
On a try I made a while back on the USAAF side, in about 50 missions, British troops landed three times on continental Europe. Each time, they got pushed back into the sea.