Source:  CBI Hump Pilots Association





"The Hump" was a high altitude military aerial supply route between the Assam Valley in northeastern India, across northern Burma, to Yunnan province in southwestern China, flown during World War II. This operation was the first sustained, long range, 24 hour around the clock, all weather, military aerial supply line in history. It was a start-from-scratch operation. There was no precedent for it.

In April, 1942, China lost the Burma Road, its last remaining supply line to the outside world, due to the invasion of Burma by Japanese troops. The Road extended 425 miles from Lashio, Burma to Kunming, China. China's eastern seaports had previously been closed by Japanese invasion troops and the Japanese Navy.

The United States determined a continuous flow of military supplies into China had to continue to enable the Chinese Army, and the U.S. Army 14th Air Force (formerly the American Volunteer Group (AVGs) and the China Air Task Force) in China, to remain effective and keep pressure on Japanese occupational troops, thereby denying their use as fighting forces in other parts of the CBI or south Pacific. The only means left for getting supplies to China was by air. Due to the presence of Japanese Army and Air Force in northern Burma, the only available air route to China was via the Hump route.

The Hump route was an unlikely route for regular flight operations due to high terrain and extremely severe weather. It crossed a north-south extension of the main Himalaya Mountains that ran south through northern Burma and western China. On the very north end of the extension terrain exceeded 20,000 MSL in height. Average elevations lowered to the south but did not fall below 12,000 MSL for approximately 140 miles. The routes flown fell between these two extremes.

Northern Burma was largely uninhabited except for wild native tribes. In addition to mountains, it was covered by tropical rain forest with trees reaching over 150 feet in height. River gorges of the Salween, Mekong and Yangtze Rivers exceeded 10,000 feet in depth. Uncivilized headhunter tribes existed on the southern rim of the main Himalayas in China. Severe weather existed on the Hump almost year around. The monsoon season, with heavy cloudiness, fierce rain and embedded severe thunderstorms with turbulence severe enough to damage aircraft, existed from around May into October of each year. The late fall and winter flying weather was better with many VFR days. However, heavy ground fogs, with ground visibilities down to zero/zero, occurred almost nightly during the early winter, and severe thunderstorms still occurred over the route on an irregular basis. Winter winds aloft were extreme, often exceeding 100 MPH. Most night flying had to be done by instruments from takeoff due to lack of any ground or horizon references, until well into western China.

Early flights were basically daylight operations that were often forced to the northern portion of the Hump due to the presence of Japanese fighter aircraft to the south flying out of Myitkyina, Burma. Terrain heights in this area generally averaged around 15,000 to 16,000 MSL. This was the high Hump.

The Hump initially contained few enroute navigational aids. Enroute communications were poor, and air traffic control, except for local control towers, did not exist. Aeronautical charts were very unreliable and weather reporting was very poor. These conditions slowly improved after the arrival of the U. S. Army Airways Communications Service (AACS) in August 1943. Homing beacons existed at each airfield in India and China. These homers were severely affected by weather, night effect, and static electricity that built up on aircraft. Airport instrument approaches were normally conducted to airports on homing beacons and were non-precision approaches.

Living conditions in the Assam Valley were primitive. Personnel generally lived in tents or bamboo bashas. A few lived in tea plantation bungalows or in bungalow outbuildings. During the monsoon season bases were seas of mud. Sidewalks and tent foundations had to be elevated to stay above standing water. Temperatures during the monsoon season were extremely hot with very high humidity. Clothes and shoes mildewed within days. Food was government issued C-ration. Personnel did not eat off base for sanitary reasons. Malaria and dysentery were prevalent diseases. Water could be consumed only after purification by iodine.

Maintenance of aircraft was a serious problem due to a shortage of parts and poor working conditions. The need for maintenance was high due to the need to fly aircraft well above their normal operating limits. Work during the monsoon season mostly had to be done at night due to the heat. There were no hangers for aircraft maintenance. All maintenance work had to be done in the aircraft parking areas. Make shift covers had to be placed over engines to complete engine work during the rainy season.

The first supply mission over the Hump occurred in April 1942, when the U.S. Army 10th Air Force in India contracted with the African Division of Pan-American Airways to handle the transport of 30,000 gallons of gasoline and 500 gallons of lubricants to China for use by the B-25s of the Doolittle Raiders. The Raiders had expected to refuel in China after their April raid on Tokyo. These Pan-American aircraft were also involved in the evacuation of northern Burma in May 1942.

Regular Hump operations began in May, 1942, with 27 aircraft (converted U. S. airline DC-3s, C-39s & C-53s) and approximately 1,100 personnel from New Malir Air Base, a British base located in the Sind Desert about 20 miles east of Karachi in western India. The aircraft and personnel were members of the First Ferry Group, provided by the U.S. Army Air Forces Ferry Command. The Group was attached to the U.S. Army 10th Air Force, newly established in India and headquartered in New Delhi, for logistical support. Their first regular Hump operations crossed India and eventually jumped off for the Hump leg of their flights from Dinjan, a British Air Base located in the upper Assam Valley. During April and May approximately 96 tons of supplies were delivered to China.

The 1st Ferry Group moved to the Assam Valley in August of 1942 where several bases were still under construction for the Hump operation. Initially these operations were conducted on sod and steel mat airstrips. On December 1, 1942, the Air Transport Command (ATC), formed on 7/1/1942 from the Ferry Command, established an India-China Wing, also headquartered in New Delhi. This ATC Wing was then assigned the primary mission of flying supplies over the Hump route to China. The first Wing commander was Colonel (later Brigadier General) Edward H. Alexander. The aircraft and support personnel of the 1st Ferry Group were transferred to this Wing.

The ATC was a world wide Command that reported directly to the War Department in Washington, DC rather than to Theater Commanders. The Wing assigned the immediate responsibility of flying the Hump to the Assam-China Group, headquartered at Chabua Air Base in the Assam Valley, under the command of Colonel Tom Rafferty, former commander of the 1st Ferry Group. In the fall of 1943 the Wing was divided into Sectors with the East Sector, based at Chabua under the command of Colonel Thomas O. Hardin, continuing with the responsibility for the Hump operation. Colonel Hardin shortly afterward implemented an all-weather, around the clock Hump operation. On October 15, 1943, command of the Wing was transferred to Brigadier General Earl S. Hoag. On January 21, 1944, Colonel Hardin was promoted to Brigadier General and on March 15, 1944, assumed command of the India-China Wing. At this time the Wing became the ATC India-China Division and the Sectors became Wings. Concurrently the Division Headquarters office was moved to the Hastings Mills complex in Calcutta. On September 3, 1944, Major General William H. Tunner became the fourth and final commander of the India-China Division.

Initially the Hump was flown with converted Douglas DC-3, C-39, C-53 and military Douglas C-47 aircraft. Loads over the Hump grew slowly until the arrival of Consolidated C-87s (converted B-24s) in December 1942 and the Curtiss C-46 in April 1943. The C-46 was a large super-charged twin-engine aircraft capable of flying faster, higher and carrying heavier loads than the C-47. The C-87, and its C-109 tanker modification, was a supercharged four engine aircraft capable of flying higher and faster but with smaller loads than the C-46. With these aircraft loads over the Hump reached 12,594 tons in December, 1943. Loads continued to increase in 1944 and 1945, reaching its maximum capacity in July 1945.

A military offensive against the Japanese Army began in February, 1944. By August, 1944, this offensive had forced the Japanese Army south far enough to enable the Hump operation to move south over the lower Hump with elevations generally not over 12,000 MSL. This move increased the efficiency of the operation. Douglas C-54 aircraft were added to the operation in the fall of 1944 for further efficiency. The C-54s were based in the Calcutta area and crossed the Hump on the south end. This reduced the need to haul materials by rail to the Assam Valley for transport.

In July, 1945, 77,306 tons of supplies were flown over the Hump to China. At that time the ATC was operating 622 aircraft, supported by 34,000 U. S. military personnel and 47,000 civilian personnel.

Loads carried over the Hump were many and verified. The primary load was gasoline, carried in 55 gallon drums and added to by siphoning from tanks of the carrying aircraft. Also carried were: small arms and ammunition, small vehicles, heavy equipment cut up and carried in pieces, truck and aircraft engines, bombs and aircraft machine gun ammunition, mortar shells, hospital equipment, personnel, 20' lengths of 4" pipe, etc.

All operations over the hump required use of oxygen. Oxygen was provided to crewmembers by a demand system which provided oxygen on inhale. It also had a constant flow and an emergency forced flow capability. Oxygen masks were very uncomfortable. Regulations required that oxygen be used above 12,000 MSL during daytime and above 10,000 MSL at night.

Initially search and rescue efforts to find downed aircraft were informal and spasmodic. About August, 1943, search and rescue took a more formal approach with the establishment of a Search and Rescue group by the ATC. Equipped initially with C-47 aircraft and later with B-25 aircraft, this group swept the mountains and jungles of Burma and the mountains of western China at low altitudes in search of downed aircraft. This group proved very successful in finding and helping downed crews return to safety. PT-17s, L-4s and L-5s of the group flew out many downed airman.

Operations ended over 3 years later on November 15, 1945, when the Hump was officially closed down. The last full month of war-time operations was July, 1945. Military supply operations were discontinued in August, 1945. The final months of operations provided for the closing of China Hump bases and the moving of support personnel from China to India for transportation home.

The success of this operation did not come lightly. Official records of Search and Rescue were closed at the end of 1945. Their final records showed 509 crashed aircraft records "closed", and 81 lost aircraft still classified as "open". Three hundred twenty-eight (328) of the lost aircraft were ATC. Thirteen hundred fourteen (1,314) crew members were known dead, 1,171 walked out to safety, and 345 were declared still missing.

Aircraft from other Air Force Commands also operated over the Hump routes during this time period. The China National Airways Corporation (CNAC), a civilian Chinese-American airline, owned jointly by the Chinese government and Pan-American Airways, flew the route primarily in DC-3s, C-47s and late added C-46s during the entire period and were a very prominent part of the Hump operation.

Troop Carrier Command Squadrons, assigned to the U.S. Army 10th Air Force and flying C-47s, entered the theater in January 1943. Their primary mission was to support combat and supply operations in the Theater. They flew the Hump routes irregularly as required by their primary mission. Some of their squadrons flew the Hump regularly during the last few months of the war following the cessation of ground activities in Burma.

The 1st Air Commando Group (initially the 5318th Provisional Unit (Air)) was a special Air Force unit initially developed for action in Burma to support the British Chindit expeditions into Burma. The Group was comprised of Douglas C-47s, CG-41 Waco gliders, Noorduyn C-64 Norseman cargo aircraft, Vultee L-1 liaison aircraft, Stinson L-5 Sentinels, the Sikorsky Helicopter, the YR-4, the first helicopter to be used under combat conditions, P-51A Mustangs for fighter cover and B-25 medium bombers. This unit first saw action in March 1944. The Group was under the joint command of Lt. Col. Philip G. Cochran, a fighter pilot from North Africa, and Lt. Colonel John R. Alison, formerly with the 23d Fighter Group of the U.S. 14th Air Force in China.

The 20th Bomber Command, of the 20th Air Force, arrived in the theater in April, 1944, flying B-29s, very heavy bombers. Their home bases were located at Kharagphur and 4 other air bases about 75 miles west of Calcutta, India. They were accompanied by three Air Transport Squadrons that flew C-46s in logistic support of this Command. The 20th departed the theater in March, 1945. During this period these B-29s and C-46s regularly flew the Hump in support of their primary mission, which was to bomb the southern islands of Japan from their forward bases in Chengtu, China.

Four squadrons of the 1st Combat Cargo Group, also assigned to the 10th Air Force and flying C-47s, arrived in the theater beginning in May 1944. Additional Groups soon followed. Together with the Troop Carrier Squadrons their primary mission was to support American and Chinese Ground Forces in the 1944-45 Burma offensive. Supplies delivered included those necessary to keep the fighting forces on the ground operating effectively. Reluctant mules were often included among these supplies. Supplies were delivered by aerial drops where no landing fields were available. These aircraft also provided troop replacements and aerial evacuation of the sick and wounded, often operating out of fields in close proximity to enemy forces. Near the end of this offensive some of their units were also assigned to fly the Hump regularly. Also flying the Hump on an irregular basis were aircraft of the U.S. 14th Air Force, the British Royal Air Force and the Royal Australian Air Force.

An additional significant aerial supply operation also took place in the theater during this time. Aircraft of the Troop Carrier Command, flying C-47s, provided aerial supply support to American and British stealth forces operating in Burma during 1943.

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