Flying ‘the hump’: the US pilots who navigated treacherous skies above the Himalayas in WW2

“No matter what advances the Japanese may make, ways will be found to deliver airplanes and munitions of war to the armies of Generalissimo Chiang Kai-shek.”

This was a pledge from President Roosevelt in 1942, declaring America’s unwavering support for Nationalist China. In April 1942, Japanese forces had invaded Burma [today known as Myanmar] and captured the Burma Road, China’s only remaining line of supply with the outside world.

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This pledge from the US set in motion two epic operations central to the American China-Burma-India (CBI) theatre: the construction of a new land route to China [known as the Ledo Road], and the creation of an “aerial Burma Road”, that would ferry supplies from India to China – climbing over the foothills of the Himalayas to pass over mountains at a height of more than 18,000ft.

A route loaded with hazards

The hazards of an air route from Assam, in north-east India, to Kunming, in Yunnan province, China, had been starkly obvious from the very first reconnaissance reports of the route, which had noted that the land was “high and rugged” and the “weather is usually bad”. The reports noted that if conditions became worse than what the reconnaissance flight had encountered, “with bad cross winds or a bad icing condition, or if the tops of the clouds should be two or three thousand feet higher than we saw, then it would be extremely dangerous and costly and very nearly impractical.”

The route, as was quickly learned, passed through a turbulent convergence of three major weather systems: two moist, warm, high-pressure masses spawned by the Sea of Bengal to the west and the South China Sea to the east, and frigid, dry lows from Siberia and Tibet to the north. This unique convergence spawned titanic thunderstorms, monsoons and, most fatally, ice.

This unique convergence spawned titanic thunderstorms, monsoons and, most fatally, ice

The pilots would have been extremely conscious of the snowcapped peaks somewhere not far below them. They were flying blind in instrument conditions (weather conditions that require pilots to fly using mainly instruments), with no radio beacons or directional aids except a compass, and against wind forces strong enough to drive aircrafts far off course. Passing over the hump of mountainous ridges on the Burma/China border, the route was soon known simply as “the Hump”; then, as aircraft crashes and losses mounted, as “the aluminum [sic] trail”, after the wreckage of crashed aircraft that shadowed the route.

The pilots who flew ‘the hump’

Every pilot had his own worst flight story. One pilot, Paul Quinnett, told in a 1981 volume of Hump Pilots Association, of his experiences at daybreak one morning, flying the route.

“We entered a solid cold front at 16,000 indicated. Our wing boots had been removed and as there was no de‑icing fluid available, we flew bare. Suddenly the entire plane began to vibrate... What we saw was a thick build‑up of clear ice... The altimeter took a nose dive and I or­dered the crew to prepare to bail out and I would remain and at­tempt to get rid of the ice, as we were by this time, I was certain very close to the mountain tops.”

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A civilian registry of crashes over ‘the Hump’ shows the loads that these aircraft carried, including detail of one Air Transport Command plane that was on a routine flight from Jorhat, India to Yangkai, China.

“This aircraft was carrying ammunition, gasoline, and ten one thousand pound bombs. Ice began building up and it took 53 minutes to get up to 26,000 feet. By that time one engine had seized, a second was leaking oil, and a third was on fire. The pilot ordered the crew to bail out, and began a series of swallow-swoops to maintain air speed.”

Bailing out was fraught with challenge, as the registry shows. “The crew tried to open the rear hatch, but the pins broke on the release handle. They opened the right rear hatch and the pilot gave the signal to go. The lone survivor Sgt Paul Beauchamp landed safely, and with the help from friendly Tibetan natives, walked out to the Burma road and encountered an English missionary; He then walked on until he reached the Chinese army, this was 38 days after the crash of his plane.”

“Say nice things about China”

At the start of the Hump operation, Generalissimo Chiang Kai-shek had demanded – and been promised – that 5,000 tons of supplies would be flown every month to China. As the fledgling air supply line struggled, often unsuccessfully, to reach this goal, the goal posts were moved – first to 7,500 monthly tons, then to 10,000. The recapture of a key air base at Myitkyina in Burma, in August of 1944 allowed a safer, lower, and more southerly route, and by the end of the war US Air Transport Command planes were ferrying an average of 41,482 tons a month over the foothills of the Himalayas.

Meanwhile, the Americans’ fixation on China, and their catering to Chiang’s ever escalating demands, bewildered and frustrated the British.

“Why the Americans attached such importance to Chiang [Kai-shek] I have never discovered,” Field Marshal Lord Alanbrooke, Chief of the Imperial General Staff, wrote in his memoir. “He had nothing to contribute to the defeat of the Germans, and for the matter of that uncommonly little towards the defeat of the Japanese.”

Roosevelt was intent on establishing a rock-solid relationship between the US and China

Roosevelt, however, looking to the post-war order, was intent on establishing a rock-solid relationship between the US and China, which he foresaw would fill the power vacuum left by the inevitable collapse of European colonies in the East.

Serving as a guide to his administration’s policy was a report that his economic adviser Lauchlin Currie had made on return from a fact-finding mission to China in February 1941. Despite finding that Chiang Kai-shek was a brutal dictator, with a spy network so feared that he had been able to get “virtually nothing from an interview in which there were two Chinese present,” Currie had concluded that, “I think Chiang can be held in line with a little care and attention from America.”

Currie’s report had continued: “I think it most important, in addition to giving material aid, to go out of your way to say nice things about China and to speak of her in the same terms now used toward England... China is at a crossroads. It can develop as a military dictatorship or as a truly democratic state. If we use our influence wisely we may be able to tip the scales in the latter direction.”

What the ‘hump’ route achieved

Today, an estimated 594 US Army Air Transport Command aircraft lie strewn on mountainsides and in jungles across the old Hump route.

An estimated 594 US Army Air Transport Command aircraft lie strewn on mountainsides and in jungles across the old Hump route

As for the Ledo Road, as the British had predicted, it served little practical purpose, and by the latter part of 1945, was already seen to be disintegrating. Most obviously, a close relationship between American and China in the post-war world was not achieved. This failure was not something to be touted – a fact that undoubtedly accounts for the obscurity of the China-Burma-India theatre’s epic exploits today.

Caroline Alexander is the author of Skies of Thunder: The Deadly World War II Mission Over the Roof of the World (Viking, 2025). Hear more from Caroline in an episode of the HistoryExtra podcast, when she joined Elinor Evans to share more about the experiences of US pilots who flew this route. Listen to the full conversation