out of control when encountering even mild icing conditions over the mountains. One Hump pilot called the variant "an evil, bastard contraption" and a "ground-loving bitch" that "could not carry enough ice to chill a highball". Despite its shortcomings, the C-87 was valued for the reliability of its engines, speed that enabled it to reduce significantly the effect of head and cross winds, a service ceiling that allowed it to surmount most weather fronts, and range that permitted its crews to fly "pressure-front" patterns that chased favorable winds. Another Liberator transport variant, the C-109, carried gasoline in converted B-24Js or B-24Ls. All combat equipment was removed and eight flexible bag fuel tanks were installed inside the fuselage with a 2,900 U.S. gallon capacity. 70 were initially planned to fly the Hump with XX Bomber Command, beginning in September 1944, but most of the 218 C-109 conversions eventually served in the CBI under ATC after B-29 operations were shifted from China back to India. At least 80 were involved in major accidents between September 1944 and August 1945. Like the C-87, they were not popular with their crews, since they were very difficult to land when fully loaded, particularly at airfields such as Kunming's above in elevation, and often demonstrated unstable flight characteristics when all eight cargo tanks were full. A crash landing of a loaded C-109 inevitably resulted in an explosion and crew fatalities, earning it the nickname "C-One-Oh-Boom". The Curtiss C-46 Commando began to fly India-China missions in May 1943. The C-46 was a large twin-engine aircraft capable of flying faster and higher than any previous medium-range cargo aircraft, and could carry heavier loads than either the C-47 or the C-87, albeit at two and one half times the unit cost for a C-47. With the C-46, airlift tonnage increased significantly, surpassing objectives with 12,594 tons in December 1943. Loads continued to increase throughout 1944 and 1945, reaching an all-time maximum tonnage in July 1945. Performance of the Commando was enhanced when camouflage paint, standard on all USAAF aircraft until February 1944, was removed to reduce weight and provide five extra knots of speed. While becoming the medium-range workhorse of the Hump airlift, the C-46 throughout its service experienced frequent mechanical failures (in particular, a tendency to engine failure and fuel leaks that puddled at the wing root to become an explosion hazard) that led to such unflattering sobriquets