Over the Hump

Dr. V. K. Sashindran

Flying over the Himalaya

While Europe was preoccupied with the war on its Western front and the United States, with the Pacific theatre, important events that had a potential to affect the outcome of the Second World War (WWII) occurred in a remote corner of north-eastern India. By early 1942, the Japanese had blockaded almost all the sea ports of China and were steadily moving towards Burma and India. A modicum of resistance to their advance was being offered by Chiang Kai-shek's People's Liberation Army. This army was based in Kunming. In this scenario, the Burma Road from Lushai to Kunming was vital for moving supplies to the beleaguered army of Chiang Kai-shek. In April 1942, the Japanese moved into southern Burma and cut off the Burma Road. The war in this region, referred to as the China-Burma-India (CBI) theatre seemed to have reached a predictable finality (Map 1). It was vital to keep the Japanese engaged in South East Asia. Surrender here would free a million Japanese soldiers to fight in the Pacific theatre and this would have been detrimental to the American war effort there. It was with this perspective that the 'Over the Hump' operations were conceived. Functioning against all odds, the heroic pilots accomplished what was probably the largest aerial operation in history, only second to the Berlin air-bridge.

Background

Chiang Kai-shek entered national politics in 1928 when he succeeded Sun Yat-sen as the head of the Koumintang, the Nationalist party. His main focus was on unification of China and ridding it of the communists. In the initial years, he was successful in his endeavours and became the head of the government in 1930. He spent the first few years reforming the financial system, building roads and improving education. Preoccupied with his mission, he chose to ignore the growing Japanese threat. Japan conquered Manchuria in 1931 and then turned its gaze southwards. By 1937, it had occupied most of the Chinese cities and the embattled Generalissimo was forced to abandon his capital Nanking and move to Kunming and also team up with the Communists to fight the aggressor. But help was forthcoming from a distant shore.

American engagement in China started in 1937, when Madame Chiang Kai-shek took over as the secretary of the Chinese Aeronautical Commission and started reorganising it. Through her contacts in the US, she was able to commandeer the services of Claire Lee Chennault, a retired US captain who was famous for his aerobatics team. They set about organising the fledgling Chinese air force on the lines of the US air force. By 1939, the Japanese had started incessant bombing on Chinese cities with the aim of breaking the back of the Chinese resistance. This prompted Chiang kai-shek to send Chennault to the US to seek help in the form of American aircrafts and pilots. There was a lot of opposition to Chennault's views on the course of the war in the American military establishment. 'My plan proposed to throw a small but well-equipped air force into China. Japan, like England, floated her life blood on the sea and could be defeated more easily by slashing her salty arteries than by stabbing her heart. Air bases in Free China could put all of the vital Japanese supply lines and advanced staging areas under attack.' Fortunately for him he had backers among the Presidential staff and on 15 January 1941, an unpublished executive order from President Roosevelt permitted reserve and enlisted men to resign from the Army Air Corps, Naval and Marine air services for the purpose of joining the American Volunteer Group (AVG) in China. Britain waived its order of 100 P 40 Bs which were diverted to China. Thus was born the first AVG nicknamed the 'Flying Tigers.' They operated from 4 July 1941 to 4 July 1942. This motley crew gave the Allies their first victory anywhere in the world since the Americans entered the War.

On 5 May 1942, Japan's elite Red Dragon Armoured Division approached the last barrier to China's back door - the mile deep Salween river gorge. If the Japanese crossed the river, China would be out of the war. The Flying Tiger P-40s and the Chinese ground forces destroyed the bridge. The Japanese then tried to cross the river using pontoons. Chennault's Tigers destroyed them and also inflicted heavy damage on the trucks and tanks that snaked for miles on the river bank. The remnants of Japan's elite army turned back on 7 May 1942. An invading army had never before been defeated solely by air power. This fighter group also has the distinction of the best ratio of kills to losses in aerial war history. Maintaining this aerial fighting force with continuous supply of fuel, ammunition and spare parts was possible because of roads connecting Kunming to the Burmese sea port of Rangoon.


In April 1942, the Japanese overran Burma and captured Lashio thereby cutting off China's vital supply line - the Burma Road. This road, 1154 km long, ran from Lashio in Burma to Kunming in China. The construction of the road from Kunming to the Burmese border started in 1937 during the Second Sino-Japanese War and was completed in 1938. Two hundred thousand Chinese labourers toiled to cut this road across the Santsung mountain range and the Salween and Mekong rivers. After the blockade of the Chinese sea ports by the Japanese, this road became vital for sending supplies to Chiang Kai-shek's beleaguered forces. When even this road was blocked, the way out seemed to be a road from India to China bypassing Japanese- occupied Burma.

Thus was born the Ledo Road, later renamed as the Stilwell Road after General 'Vinegar' Joe Stilwell the American General in charge of the project. The road was based on a survey carried out by British railway surveyors in the nineteenth century. They had studied the feasibility of a railway line cresting the Patkai range at the Pangsau pass (3727 ft) above Nampong in Arunachal Pradesh and then descending into Burma through the Hukawng valley. It was envisaged that the road would run from Ledo in (then) Assam across the Pangsau Pass, nicknamed 'Hells pass', for its treacherousness; and then to Shingbwiyang in Burma. From there, the road, passing through Warazup, and Myitkyina and Bhamo would join the old Burma Road at Mong-yu and then continue further to Wandingzhen (Wanting) on the Chinese border [1] (Map 2).

It was thought that 65,000 tonnes of supply could be transported to China per month on this road. But the road belied its expectations. Work on the first section of the road started in December 1942. To reach Mong-yu, the road had to span 10 major rivers and 155 smaller streams averaging one bridge every 4.5 km. Fifteen thousand American and thirty-five thousand locals laboured on the road. One thousand one hundred Americans and countless others lost their lives justifying the soubriquet of 'Mile a Man road' [2]. The steep gradient, dense forests, heavy monsoons and floods made road construction a Herculean effort. Flying over the Hukawng valley one monsoon, Lord Mountbatten, asked the name of the river below. An American officer remarked, 'That's not a river, it's the Ledo Road' [3]. The practicality of the road project has always been debatable. Field Marshal William Slim, the Commander of the British 14th Army in Indo-Burma wrote, 'I doubted the overwhelming war-winning value of this road, and, in any case, I believed it was starting from the wrong place' [4]. By late 1944, the road had not yet reached China. The first convoy of 113 vehicles, led by General Pick, departed from Ledo on 12 January 1945 and they reached Kunming on 4 February, 1945. In the six months following its opening, trucks carried 129,000 tonnes of supplies from India to China [5, 6, and 7]. Sir Winston Churchill had been prophetic when he had remarked that the project was 'an immense, laborious task, unlikely to be finished until the need for it has passed'. Moreover the aerial supply route used in the interim was far superior to the road in terms of time, man, machine, and money [8].

Hump Operations

Though the Ledo road construction started in earnest after the Japanese cut off the Burma Road, the Chinese were desperate. Chiang Kai-shek wanted seven-thousand-five hundred tonnes of supplies every month to keep his 500 aircraft-strong air force and ground forces fighting [9]. The only way that his demands could be met was by an aerial route over the eastern-most flank of the Himalaya. And thus was born the Hump operation - an aerial supply operation from bases in north-east India, across the eastern most spur of the Himalaya and the Santsung range lying parallel to it further east, to Kunming in China.


The Hump operation was without precedent. It was the first sustained, round-the-clock, all-weather, long-range military aerial supply line in history. It is also a story of a deep Sino-American engagement which later got buried in suspicion and Communist propaganda of post-War China. The early effort was mainly by the China National Aviation Corporation (CNAC). This company was setup in 1929 by the Chinese government in partnership with Curtiss-Wright Corporation and later between the Chinese government and Pan American Airways. In November 1941 the CNAC did the first reconnaissance flight across the Hump. After April 1942 they quickly swung into operation.

Aircrafts for the operations were commandeered from domestic American airlines and the pilots were recruited from the Pan American Airways and also from the American Volunteer Group. The crew consisted of both Americans and Chinese personnel. The CNAC aircrafts made more than 38,000 trips over the Hump, transporting approximately 114,500 tonnes of vital personnel and materials to the Chinese and American forces in the CBI theatre. They also played an important role in the Burma campaign by dropping supplies to Allied ground forces, evacuating troops and supplying the Ledo Road Project with men and equipment. Realising that the CNAC could not sustain the Chinese war effort alone, the US Government charged the 10th Air Force with the Hump operations in April 1942. However, the CNAC continued to operate all through the War. In October 1942, General of the Air Force Henry H. 'Hap' Arnold decided to put the Air Transport Command (ATC) in charge of all Hump operations, and the 10th Air Force units on Hump assignments were transferred to the ATC in December. The CNAC had to now work with the ATC but they had different operating philosophies. The former was a commercial organisation where time, pilots and aircrafts, all counted while the latter was a part of the gargantuan American war machine that believed that the job must go on irrespective of the cost. In the book The Dragon's Wings, William Leary wrote, 'CNAC became the yardstick of efficiency for the massive undertaking by the Air Transport Command' [10]. This is amply illustrated by the data in Table 1.

Table 1. CNAC and ATC Operations in CBI Theatre
CNAC ATC
Total flights over the Hump 38000 167,285
Total tonnage of freight 114,500 740,000
Tonnage per flight 6 3
Tonnage per airplane 1154 342
Airplanes at end of WWII 52 772
Personnel at end of WWII 2000 84664
Personnel per aircraft 38 110
The Hump operations began with the CNAC using C-47 Douglas aircrafts and the ATC using DC3s, C-39s and C-53s. However, these aircraft were ill-suited to high-altitude operation with heavy payloads, and could not normally reach an altitude sufficient to clear the mountainous terrain, forcing the planes to attempt a highly dangerous route through the maze-like Himalayan passes [11]. In the month of April and May 1942, they managed to transport a paltry 96 tonnes [12]. The Consolidated C-87s (converted B-24 bombers) were inducted in December 1942 and its tanker modification (C-109) subsequently. These planes climbed poorly with heavy loads and often crashed on takeoff. They also tended to spin out of control after mild icing over the mountains [13]. The Curtiss C-46 aircrafts were inducted in April 1943. These aircrafts permitted faster transport and loads over the Hump reached 12,594 tonnes in December 1943. Loads continued to increase in 1944 and 1945. Early in 1945, the monthly cargo delivered to China reached 44,000 tonnes - peaking at 77,306 tonnes in July [14]. General William H Tunner who took over command of the ATC in August 1944, played a significant role in increasing the efficiency of the operations. He introduced factory-line maintenance of aircrafts, jungle indoctrination for new recruits, malaria prevention measures, fighter escorts for the transport aircrafts and search and rescue missions.


Increases in tonnage came at great cost. In the last six months of 1943, there were 155 accidents and 168 fatalities. The toll at the end of the operations is shown in Table 2. The US Department of Defence estimates put the toll at more than 500 aircrafts and 1200 aircrew with 416 missing in Indian Territory alone. 'It was safer to take a bomber deep into Germany than to fly a transport plane over the Rockpile from one friendly nation to another,' - General William H Tunner

Table 2. CNAC and ATC Losses in CBI Theatre
CNAC ATC
Total planes used 91 2161
Planes totally wrecked 37 1404
Total deaths 81 3861
The cause for this high toll was multi-factorial. It was an unforgiveable terrain. The Hump route was an aerial route from northeastern India, across Burma to western China. It crossed over a generally north-south spur of the Himalaya that ran south of Tibet and formed a natural border between China and Burma. The highest elevations along the route extended from approximately 19,500 ft above MSL to the north to approximately 12,000 ft above MSL to the far south. The lowest pass on this spur was at an altitude of 10,500 ft (Map 2). The western part of the route was over the dense forests of Arunachal Pradesh, Assam and Burma with trees as tall as 150 feet and further east were river gorges up to 10,000 ft in depth carved out by the tumultuous flow of the Yangtze, Salween and Mekong rivers. These uncharted forests were home to head-hunters and other tribes who had never come in contact with Western civilisation. Coming out alive from them after a crash was thought impossible and not surprisingly this area was referred to as the 'graveyard of the Himalaya.' A description of the flight across the Hump succinctly describes the awesome terrain - 'Flying eastward out of the valley, the pilot first topped the Patkai Range and then passed over the upper Chindwin river valley, bounded on the east by a 14,000- foot ridge, the Kumon Mountains. He then crossed a series of 14,00016,000-foot ridges separated by the valleys of the West Irrawaddy, East Irrawaddy, Salween, and Mekong Rivers. The main "Hump," which gave its name to the whole awesome mountainous mass and to the air route which crossed it, was the Santsung Range, often 15,000 feet high, between the Salween and Mekong Rivers.'

If the terrain was forbidding, then the weather patterns there were more disconcerting. Severe weather existed year round. The monsoons were the worst with dense clouds, heavy rain and embedded thunderstorms. Thunderclouds 3000 ft high would suddenly mushroom out of the valleys. The rainy season lasted from May to October. High speed winds up to a speed of 160 kmph were common in winters at flying altitudes. Though winters had maximum fair weather days, ground fogs with zero visibility were common at nights. Even in winters, thunderstorms still occurred and one had to be really vigilant.

Poor visibility compounded the problems of flying without reliable maps and navigational aids. Since fixes by radio or visual ground checks were impossible when flying between two main terminuses on instruments, dead reckoning was the only method of navigation on the Hump route. Since this method of navigation was not very exact, the degree of error determined pilot's survival. Wind direction and velocity were factors which most often led to error in dead reckoning.

Flying infrastructure was poor. Maps and charts of the area were unreliable and weather reports poor. Air traffic control only existed at the bases and was not available during the flights. Homing beacons were located at the bases but their functioning was affected by weather, night effect and build up of static electricity in the aircrafts. When operations started, the CNAC operated out of Dinjan, and the ATC out of Chabua. By the end of the war the ATC was operating flights from 13 airfields in India to six airfields in China across the Hump. Accommodation for aircrew at the bases was primitive. They lived in tents or bamboo shelters. The heat, humidity and frequent flooding made life miserable. This was only compounded by debilitating malaria and dysentery.

Painting on one of the fallen planes.

Painting on one of the fallen planes.



Aircraft maintenance was critical. Most aircrafts frequently flew well above their operating limits and this led to rapid wear and tear. Spare parts were in short supply and it was not unusual to send ground crew to cannibalise aircrafts that had crashed. Crashes on the Hump route were so common that the trail was littered with aircraft debris and thus was referred to as the aluminium trail. There is a story of an aircraft which crash-landed on a sand bank in the Brahmaputra. Like something straight out of Ripley's Believe it or Not, the aircraft was repaired on the sand bank, the earth firmed to serve as a make-shift runway and the aircraft flown out safely. Maintenance personnel were inexperienced and worked under severe handicaps. There were no hangars and most work had to be done in the open. Col. Edward H. Alexander, Commander of the India-China Wing, reported, 'Except on rainy days, maintenance work cannot be accomplished because shade temperatures of from 100o to 130o Fahrenheit render all metal exposed to the sun so hot that it cannot be touched by the human hand without causing second-degree burns.'

The pilots who flew the Hump were the real heroes of the operations. Most of the CNAC pilots were volunteers who probably only flew the route for the adrenaline-high it gave them. Flying aircrafts above the stipulated altitude ceiling, with loads much above permissible limits and with irregular oxygen supplies was a daily routine for them. The CNAC flew through the Pimaw pass across the Hump. This, at 10500 feet, was the lowest point on the Hump. This route allowed them to fly below thunderstorms and allowed them to save gasoline and helped engines last longer. These benefits came at a tremendous risk - they flew across the Pass with fifty-foot clearance at the end of each wing. Then, these were not always seasoned pilots. Aircrew were always in short supply. Many were new recruits put on the route after a few training flights. Pilots, most of whom had never before flown a twin- engine aircraft, were quickly recruited from among basic flying training school instructors in the Air Training Command. Once they had cut their teeth, they flew more than 100 hours per month - averaging three trips daily. One wonders what kept these pilots on the job. The sheer thrill of the risky flight apart, rest and recuperation breaks at Calcutta with its bars clubs and swimming pools was a great motivating factor for the pilots. Some also made a tidy sum; racketeering in medicines, arms, Chinese government bonds and human cargo. Notwithstanding all this, their effort was heroic and commendable. Quoting General Albert Wedemeyer, Commander American Forces in China - 'Flying the Hump was the foremost and by far the most dangerous, difficult and historic achievement of the entire war.'

Conclusion

The Hump operations came about as a desperate measure to keep the Japanese engaged in South Asia. What started off as a mission fraught with hazards and failure turned out to be one of the most remarkable aerial achievements of the WW II. A war machine with robotic efficiency was created; on 01 August, 1945, the ATC flew 1,118 round trips with a plane crossing the Hump every minute and twelve seconds. The total payload moved was 5,327 tonnes with a tonne of material landing in China four times every minute. And, all this accomplished without a single accident. The operations ended over 3 / years later on 15 November, 1945, when the Hump was officially closed down. A total of more than 850,000 tonnes of material and 33,400 people were transported over 1.5 million flight hours. Today the Stilwell road across the Patkai hills is not in regular use. Insurgency has limited free movement across the Indo-Burma border. The road from Nampong to Pangsau pass is passable in four-wheel drive vehicles. Parts of the Burma Road between China and Burma have been improved with the help of the Chinese. Numerous aircrafts and human remains stay scattered all over the jungles in this sector. Some have probably never been sighted since they crashed. In 2008, the Government of India gave the US Joint Prisoners of War and Missing in Action Accounting Command (JPAC) permission to search for human remains at the site of a crashed B24 Bomber in Arunachal Pradesh. The final closure of the cases of aircrew missing in the CBI theatre has finally begun.

References

1. Weidenburner, Carl Warren - Mile posts and time line

2. Sankar Anand (2009-02-14) - 'On the road to China' Business Standard, http://www.business-standard.com/india/storypage.php?autono=323868. Retrieved on 2009-02-13.

3. Moser Don - 'China-Burma-India: World War 2', Time-Life Books (1978) p. 139

4. Slim William - Defeat into Victory, ISBN 1568490771, Chapter XII : 'The Northern Front'

5. American Embassy in China - 'U.S. Embassy Marks 60th Anniversary of Ledo Road,' U.S. Embassy Press Briefing and Release, February 2, 2005

6. Schoenherr Steven - The Burma Front, History Department at the University of San Diego

7. Xu Guangqiu - War Wings, The United States and Chinese Military Aviation, 1929 - 1949. Westport, Connecticut, Greenwood Press ( 2001), ISBN 0- 313-32004-7, p. 191

8. Air Force Association - Flying The Hump http://www.afa.org/magazine/ 1991/0391hump.asp

9. CBI Background - 'CBI Order of Battle, Lineages and History: China Defensive Campaign, 4 July 1942-4 May 1945,' http://www.cbihistory.com/ part_xii_china_def.html]

10. Leary William M - Dragon's Wings : China National Aviation Corporation and the Development of Commercial Aviation in China,.

University of Georgia Press (1982), ISBN-10: 0820303666

11. Gann Ernest - Fate Is The Hunter, New York : Simon & Schuster (1961), ISBN 0-671-63603-0, p. 263

12. CBI Background - 'CBI Order of Battle, Lineages and History : China Defensive Campaign, 4 July 1942-4 May, 1945' http://www.cbi-history.com/part_xii_china_def.html
13. Gann, Ernest - Fate Is The Hunter, New York : Simon & Schuster (1961), ISBN 0-671-63603-0, p. 256

14. CBI Hump Pilots Association - Flying the Hump : A Fact Sheet for the Hump Operations During World War II (USAAF) China-Burma-India (CBI) Theater of Operations http://www.cbi-history.com/part_xii_hump5.html
Summary :

A study of 'The Hump' operations during World War II.