Complex sentence: Both offered more accuracy than was really needed, and as both were not going to be available immediately, in 1939 the Royal Aircraft Establishment started examining a simpler solution under the direction of P.M.S. Blackett.
Split into simpler sentences: Both offered more accuracy than was really needed, and neither was going to be available immediately. Accordingly, in 1939 the Royal Aircraft Establishment started examining a simpler solution under the direction of P.M.S. Blackett.