When Japan cut the Burma Road in 1942, the only way to keep China in the war was by air, over the eastern end of the Himalayas from bases in Assam to Kunming. The airlift began in April 1942 with whatever aircraft were available, mostly C-47s. The C-46 began flying Hump missions in 1943 and transformed the operation: it carried much heavier loads than the C-47 or the C-87 Liberator transport, and it flew at the heights needed to clear the ridges.

It was a hard introduction. The aircraft had been rushed from the factory with unresolved faults, the bases were primitive and spare parts scarce, and crews flew in monsoon storms, icing and at night over mountains with few navigation aids. Losses were heavy across the whole airlift, and the debris scattered along the route gave it the name the Aluminum Trail.

Things changed when General William H. Tunner took command of the India-China Division of Air Transport Command in September 1944. He applied production-line maintenance and strict flying standards, tonnage rose sharply and the accident rate fell. By the end of the operation the C-46 fleet over the Hump numbered several hundred aircraft, and the record monthly delivery came in July 1945. The Commando had become the backbone of the most demanding airlift of the war.

Cheap and plentiful after the war, surplus C-46s were snapped up by non-scheduled airlines, cargo operators and new air forces. A CAF history notes that surplus aircraft sold for around $20,000 to $25,000 in the late 1940s and early 1950s. The type flew for air forces from Latin America to Asia, and for the CIA-owned airline Air America in Indochina, where its load-carrying ability suited the dirt strips of Laos and Vietnam.

On 29 April 1975, as Saigon fell, Air America C-46s were among the last transports out. The company’s association records that Captain E. G. Adams flew a 52-seat C-46 to Bangkok with about 152 people inside. In Canada, Buffalo Airways in the Northwest Territories still flies two Commandos as freighters, saying they can haul up to 14,000 lb of bulky freight into short, unprepared strips.

In 1943 to 1945 a series of C-46s caught fire or exploded in the air without obvious cause. Investigators traced the problem to fuel leaking from lines and pooling in unvented parts of the wing, where vapour could be ignited by electrical sparks. Venting and other fixes cured it, but the episodes, combined with the mechanical teething troubles of an aircraft rushed into service, gave the Commando a reputation it never fully shook off with wartime crews.

The other lesson came at Varsity. Unlike many C-47s, the new C-46D paratroop carriers used on the Rhine crossing had no self-sealing fuel tanks. When flak hit them, fuel burst into flames that streamed back along the fuselage. It was the C-46’s first big combat jump, and the war ended before the paratroop version could redeem itself.

• CW-20: pressurised airliner prototype, first flown in 1940 with twin tails, later with a single fin.
• C-46A: main cargo version with large cargo doors and a strengthened floor, about 1,450 built.
• C-46D: paratroop version with doors on both sides, about 1,400 built.
• C-46F: about 234 built, with square wingtips and doors on both sides.
• R5C-1: US Marine Corps version, about 160 delivered.
• C-46E/G and XC-46B/C/K/L: small-batch and experimental versions with modified noses, engines or performance.

Two R-2800s are expensive to feed and overhaul, so the C-46 makes sense only where its particular qualities matter. In Canada’s north they do: Buffalo Airways says its two Commandos haul up to 14,000 lb of bulky freight into short, unprepared strips at an operating cruise of about 190 mph. The aircraft’s big cabin and doors take loads a modern turboprop of similar size cannot, and the airframes are simple enough to repair in remote places. For museum operators such as the Commemorative Air Force, fuel and engine overhaul dominate the bill.