During the first six months of 1941, Fighter Command lost 57 aircraft compared to some 20 German losses. Despite the cost, offensive operations over France continued in an effort to relieve the pressure on the Russians by tying down German aircraft in the West. Towards the end of the year, the first squadrons with ex-patriate Allied personnel began to form. Language difficulties, and the fact that, to open the throttle the lever was pushed forward - the opposite to most continental aircraft - led to a spate of early accidents until pilots became used to their new mounts. One welcome improvement to the Spitfire arrived in the form of a diaphragm-operated carburettor for the Merlin engine which solved the problem of the engine cutting out under negative.