In February 1942, Air Marshall Arthur Harris became Air Officer Commanding Bomber Command. Harris became the driving force behind producing a powerful heavy bomber command to carry out his area bombing operations. The attacks on Lübeck in March and Cologne in May 1942 began the new phase in the Defence of the Reich. Over Lübeck, NJG 1 claimed only one bomber from seven claimed. NJG 1 claimed 21 bombers during the latter attack on Cologne on 30/31 May 1942 from the 32 claimed by German night fighter units. 41 bombers were lost. One of the wing's first losses was Helmut Woltersdorf, killed in June 1942 against an RAF night fighter.