5 Groups Greiner infiltrated the bomber stream west southwest of the city and at 22:55 and 23:02 claimed a Lancaster destroyed. On the 23/24 September 1944 Bomber Command attacked the Dortmund–Ems Canal with several hundred bombers. West southwest of Münster Greiner claimed a Lancaster bomber at 23:16 for his 40th victory. Group commander On 1 November, Greiner was appointed Gruppenkommandeur (group commander) of IV./NJG 1. He succeeded Major Heinz-Wolfgang Schnaufer in this capacity. On 4/5 November 1944 Greiner achieved two more successes against Lancasters at 19:21 and 19:35 west of Essen. Greiner's 42nd victory was his last in 1944. On 5/6 January 1945 Greiner had his most successful patrol. Bomber Command attacked Hannover with 340 Halifax and 310 Lancaster bombers supported by 14 Mosquitos. 23 Halifax and eight Lancaster bombers were lost. Greiner claimed three Lancaster bombers in rapid succession over Hannover at 19:12, 19:15, 19:18. Greiner shot down his fourth of the night at 19:22. The claim was his 46th victory of the war. One of the bombers was Halifax LV952, MH-F, of No. 51 Squadron RAF. Only the gunner, Sergeant Don Thomsett, survived. He met Hermann Greiner in May 1998. On 21/22 February Greiner shot down two Halifax bombers near Neuss at 23:31 and 23:40. On 3 March 1945 No. 4 Group RAF was ordered to destroy the synthetic oil plant at Kamen while 5 Group would attempt to eliminate the aqueduct, safety gates, and canal boats on the Dortmund–Ems Canal at Ladbergen. Nearly 5,000 RAF airmen prepared to take part in 817 heavy bombers which were fueled and armed in the evening. The Luftwaffe planned a counter-attack this night. Named Operation Gisela, a large wave of night fighters were detailed to return with the bomber stream to their bases in England and attack them. Greiner was not scheduled to take part in the operation. His unit was ordered to engagement the incoming bomber stream. Near Dortmund at 21:57, 22:08 and 22:12 he claimed a Lancaster bomber. This brought his final tally to 51 Allied bombers destroyed—47 RAF and four USAAF. These interceptions were his last of the war. In April 1945 he was ordered to intercept a Bomber Command attack on Dessau but became disorientated. The radio ceased working and the crew were lost. Fearing they were drifting eastwards towards Soviet lines, the crew sought to find a landmark without success. Greiner was low on fuel, he