XX Bomber Command From April 1944 to January 1945, the India-China Division was also tasked with supporting Operation Matterhorn, the B-29 Superfortress strategic bombing campaign against Japan from forward bases around Chengtu in central China. Arnold originally envisioned Matterhorn units as being self-sustaining, bringing in their own fuel in hundreds of C-109s (see Transport shortcomings below) and other materiel using B-29s and 20 C-87s as their own "air transport service". The concept proved to be flawed from the outset when the planned 300-bomber force was reduced to a single combat wing of 150 bombers before it left the United States. B-29s of the XX Bomber Command, stripped of guns and other equipment and fitted with four bomb bay tanks, were used as fuel tankers while tactical aircraft hauled other supplies, including bombs, but were unable to bring enough materiel over the Hump from their permanent bases around Calcutta in India to begin missions. XX BC turned to ICD for additional support when its target date for commencement of missions was repeatedly postponed. ATC's North African Wing had already provided stopgap support by transporting 250 spare B-29 engines to the CBI in April and May 1944, using 25 C-54s over a shuttle route from the port of Casablanca to Calcutta that came to be called the "Crescent Blend" until three special mission C-46 squadrons—created in early 1944 under the code name "Moby Dick"—were ready to carry out supply operations for XX Bomber Command. Designated the 1st, 2nd and 3rd Air Transport Squadrons (Mobile), each was intended to be a self-contained unit of twenty C-46s, flight crews, maintenance and engineering specialists, and a full complement of station operation personnel, although when first committed the service elements had not yet been integrated. They arrived in the CBI in June 1944, with the 1st and 2nd MATS based at Kalaikunda, West Bengal, taking over the "Crescent Blend" shuttle and bringing in over 100 spare engines per month, while the 3rd MATS was sent forward to the ICD base at Kunming to augment the India-China airlift. Of 42,000 tons of materiel delivered before XX BC abandoned its China bases and returned to India, the ICD moved almost two-thirds. During the last three months of bombing operations from China, XX BC quickly phased out use of its B-29s to haul cargo, and ICD supplied all of XX Bomber Command's materiel except bombs, which B-29s toted over