Japan’s Fatally Flawed Air Forces in World War II

7/28/2006 • Aviation History, Battle of Manila

World War II in the Pacific was a fight to seize and defend airfields. The Japanese made gaining and maintaining control of the air as much a requirement in their basic war strategy as they did the destruction of the U.S. Pacific Fleet. But as Commander Masatake Okumiya charged, “The Pacific War was started by men who did not understand the sea, and fought by men who did not understand the air.” He might well have added that the war was planned by men who did not understand industry, manpower and logistics.

To say that the Japanese army and navy did not cooperate on aerial matters would be a serious understatement. “They hated each other,” Lt. Cmdr. Masataka Chihaya recalled, “[they] almost fought. Exchange of secrets and experiences, the common use of airplanes and other instruments, could not even be thought of.”

Japan, although seemingly advanced in aerial tactics, entered the war with a narrow aerial doctrine, insufficient numbers of aircraft and those of generally poor design (excluding the Mitsubishi A6M2 Zero, of course), too few aircrews and inadequate logistics for a war of attrition. Neither its army nor its naval air arm was prepared for the duration, violence or sophistication of the war to come. Even its short-lived lead in aerial tactics collapsed once the Guadalcanal campaign began.

Completely aside from having an industrial base able to produce enough aircraft, a nation’s air force needs to be balanced between aircraft, combat and maintenance crews, and air bases. If Japan was to seize an empire, its airfield builders would have to accompany the fighting forces every step of the way. Absent such construction units, the air force would have to use captured bases.

Army air forces were doctrinally anachronistic. Air units were subordinate to ground force commanders, not independent entities on a footing equal to ground and naval commanders. Japan’s army had developed its air forces for continental warfare with the Soviets. Naval air, on the other hand, was tied to operations of the Combined Fleet, with naval officers, rather than air officers, making major air decisions.

Admiral Isoroku Yamamoto had given some thought to a land-based air war, stating in 1936 that naval operations in the next war would consist of capturing an island, building an airfield and using that base to gain control over the surrounding waters. His ideas, however, did not take hold. The Japanese studied and trained hard at aerial tactics, but they failed to develop the airfield construction techniques and equipment, as well as the units, necessary to build air bases, maintenance, supply and dispersal facilities.

Japan launched its December 1941 attacks from well-

developed bases. During the southern advance, the navy’s 22nd Air Flotilla supported the attack into Malaya from three airfields in and around Saigon. Units were at full strength in aircraft and crews. Plentiful quantities of fuel and spare parts were available. The aircraft received excellent maintenance. Zeroes, for example, underwent a thorough overhaul every 150 hours of flight. As Japanese forces moved south, air units occupied, repaired and exploited captured enemy bases. Real problems developed, however, when those units reached undeveloped territories. Getting fuel, food and materiel to those bases determined whether the aircraft flew. Whether a base had been captured or built, however, it was nearly useless if seaborne supplies could not reach it.

Mechanical complexity, battle damage and environmental stresses meant that maintenance was key to an aircraft’s availability, its performance and whether the crew survived. Considering Japan’s stressed economy, it should have been intolerable in terms of production and transportation to accept the loss of equipment that could have been repaired. Amazingly, the Japanese tolerated those losses.

Although a nucleus of well-trained army and navy maintenance men and armorers followed their aircraft south, maintenance units lagged behind during the early advances and were too few even when they caught up with the flying units. The army responded by sending forward individual maintenance units to plug gaps in maintenance coverage. The navy reduced support of homeland air bases to a minimum, so as to reinforce forward bases. Because service personnel arrived late or were too few, maintenance — and even the building of quarters and other facilities — fell to the aircrews themselves. Those tasks sapped the energy of men whose principal duty was flying.

The more mobile a maintenance unit is, the less it can do without heavy equipment. The better a unit is at fixing things, however, the harder it may be to get where it needs to go. The Japanese were chronically short of shipping. Moving heavy maintenance units forward was always a problem. Unloading heavy equipment in locations where there were no piers, docks and roadways made air base maintenance all that much more difficult.

The army’s piecemeal commitment of aviation maintenance units was due to the original absence of any strategic plans to put large army forces into the Southwest Pacific. Rising air losses in the Solomons, however, led the navy to request that the army bring in aircraft. But without a clear long-range plan or doctrine of what to do, no one could arrange the necessary logistical support.

Depots where engines could be changed and major repairs made were few and scattered. The Fourth Air Army’s heavy equipment for engine changes and major structural repair on New Guinea, for instance, was poor. Periodic inspections, repairs, overhauls and even routine servicing fell off because of maintenance shortfalls. The Japanese had to abandon many aircraft during advances or retreats that easily could have been repaired at rear areas. Poor repair also denied them the opportunity to use worn-out aircraft in a training role.

Aviation fuel in New Guinea was of poor quality and resulted in engine problems. The army’s main aircraft repair base at Halmahera, 1,000 miles from the front lines, never functioned adequately because it lacked equipment and mechanics. High humidity and rains corroded metal parts and wires. Electrical equipment grew fungus. Lubricating oils evaporated or ran off equipment. Allied bombings killed skilled mechanics and delayed aircraft maintenance. Ground crews suffered attrition from out-of-control aircraft, spinning propellers and from working around heavy objects.

Because the army and navy did not cooperate, army aircraft on New Guinea had to fly 1,500 miles to Manila for engine changes even though the navy had major maintenance assets as close as Rabaul. Even at Rabaul, aircraft maintenance was so limited that of 60 fighters and 40 bombers that might be on hand, only a mix of 30 typically could fly on a given date.

During the advance southward, Japanese pilots fought from unimproved airstrips, most of them small and unpaved. Although Japanese aircraft generally were lighter than Western counterparts and not so much in need of paved strips, occupying enemy airfields was never easy. Gasoline trucks were scarce and could be found at only a few of the large fields. Ground crews ordinarily had to refuel aircraft with hand pumps and barrels — a tedious process that slowed aircraft turnaround and consumed manpower. Even Rabaul’s aircraft were refueled from 200-liter drums rather than from gasoline trucks.

When the Japanese navy flew its first nine fighters into the Philippine airport of Legaspi in December 1941, two of them were totally wrecked upon landing. The army flew two squadrons of Nakajima Ki-27s onto recently captured Singora Field in Malaya, and wrecked nine aircraft on the poor ground. When 27 Zeroes of the Tainan Kokutai (air group) flew into Tarakan Field — one of the worst in the East Indies — on Borneo in January 1942, two aircraft overshot the runway and were demolished. Slippery mud at that field made simple takeoffs and landings dangerous.

Half the aircraft of the 23rd Air Flotilla lost in the first three months of the war were casualties of crackups on bad runways — partially due to weak landing gear and poor brakes, but mainly from bad terrain. Another 30 percent of the flotilla’s aircraft wore out and had to be scrapped. Only 18 of the 88 aircraft it wrote off went down in combat.

Japanese naval aircraft flew into Lae on New Guinea in early April 1942. Zero ace Saburo Sakai described the strip, built by the Australians before the war to airlift supplies into, and gold out of, the Kokoda mine, as a “forsaken mudhole.” Although Japanese authorities considered it an improved airfield, it was so small that Japanese pilots compared it to landing on an aircraft carrier. Three decrepit trucks provided support there.

Japanese navy tables of organization and equipment specified that each air unit was to have extra aircraft in its organization equal to one-third the operational complement. Yet by early April 1942, naval air units had no extras and were below their authorized operating strength. The navy general staff refused urgent requests from the shore-based 11th Air Fleet for replacement aircraft because not even the higher-priority carriers were up to strength.

The navy general staff had been equally shortsighted in planning for mutually supporting air bases. Japanese officers who could see the big picture had no solution. “Nothing is more urgently needed than new ideas and devices,” Rear Adm. Matome Ugaki, chief of staff of the Combined Fleet, wrote in July 1942. “Something must be done by all means.”

No one on either side of the Pacific had foreseen serious campaigns in the Solomons and on New Guinea. In the first 10 months of war, the Japanese navy managed to complete only one new air base, at Buin on Bougainville, and it had only one runway. Important though that base was, it was a rough field, and seven of 15 Zeroes were badly damaged when they landed there on October 8, 1942. Heavy rains delayed construction, and even significant additions to the construction troops did not help much. The runway continued to be soft and slippery during rains. When flying unit ground crews arrived and reported that Buin was unfit for operations, Admiral Ugaki, rather than arranging for construction assets to properly complete the field, groused to his diary: “How weak-minded they are! This is the time when every difficulty should be overcome. Don’t grumble, but try to use it by all means!” Fliers did try — and damaged about 10 aircraft a day when the runway was wet.

The airfield at Guadalcanal bore bitter fruit when the Americans seized it just before the Japanese brought in their own aircraft. The Japanese failed to construct ferry sites and auxiliary airfields between Rabaul and Guadalcanal, 675 miles away, when they had the time. Lack of shipping to carry men and equipment for that task was the main problem, but their near total disregard of an aircraft’s combat radius was also at fault. For example, 18 Aichi D3A1 dive bombers were ditched into the sea in the first two days of the campaign when they ran out of gas.

Japan had not developed a robust civil engineering infrastructure. It did have power rock crushers, concrete mixers, mobile power saws and mobile well-drilling equipment, but bulldozers, power shovels and other earthmoving machinery were in short supply. Picks, shovels, manpower and horsepower provided the backbone of Japanese engineering activities.

Japan’s prewar military budgets had gone to warships, infantry divisions and aircraft, not to construction equipment. When war came, the hitherto-ignored lack of construction assets affected tactics. For instance, without mechanized equipment to cut dispersal areas, frontline aircraft were vulnerable to attack on the ground.

Japanese planners did have one good reason for skimping on airfield construction units. The normal bearing capacity of most soil was good enough to handle lightweight Japanese aircraft. But Japan lacked sufficient steel to turn out large quantities of steel planking while it concentrated on aircraft, warships and merchantmen, and it was short of shipping to transport it. This meant that Japan depended on manpower to construct airfields. The military used native laborers wherever it could, paid them poorly and fed them little or nothing. They worked more than 2,500 Javanese to death while building a field on Noemfoor Island.

The Japanese army had to use infantrymen to help build airfields. In December 1942, for example, the engineer regiment and three rifle battalions of the 5th Division were detailed to build airfields in the Solomons. “When we compare [our] clumsy result with what our enemy accomplished,” recalled Commander Chihaya, “building huge airfields in good numbers with inconceivable speed, we ceased to wonder why we were utterly beaten. Our enemy was superior in every respect.”

Food at Japanese airfields was bad. Barracks were jungle slums. There were no laundry facilities, and men washed themselves in rivers, or under water-filled cans. Disease felled pilots and left serviceable aircraft grounded. Physical exhaustion lowered pilot performance, so that lesser-skilled opponents sometimes shot down veteran but feverish Japanese pilots.

Manpower became critical with no tractors, and ground crews wore themselves out pushing aircraft around fields. They worked at night to avoid Allied air attacks, only to fall victim to the malaria mosquito, which was most active at night. Men worked seven days a week in wretched weather at exhausting and mind-numbing tasks. Ground crews became nervous and irritable from lack of sleep. It took longer and longer to accomplish a given assignment. Minor as well as major accidents increased.

Raw human muscle wrestled bombs, cannon shells and machine gun rounds onto aircraft. Mechanics pulled maintenance on baking hot fields in direct tropical sunlight, for there were no hangars. When flooded airstrips dried after rains, dust billowed up in the wake of each aircraft, choking cockpit interiors and eroding engines.

“The maintenance crews are exhausted, but they drag their weary bodies about the field, heaving and tugging to move the planes back into the jungle,” a navy pilot at Buin wrote in July 1943. “They pray for tractors such as the Americans have in abundance, but they know their dream of such “luxuries’ will not be fulfilled.”

Commanders and planners lacked any understanding of the vast numbers of technicians required to support a modern army. Although there had always been shortages of trained mechanics, commanders showed little interest in sending their men to the ordnance school in Japan. The service schools themselves paid little attention to logistics and engineering support of combat forces. Nor did commanders establish schools or training programs at tactical units or in geographic army areas.

Japan’s absence of standardization in weapons and equipment ranged from aircraft types to different engines, down to instruments and the smallest accessories. The army used a 24-volt electrical system, whereas the navy used a different voltage. Mounts to hold guns, cannons and rocket launchers varied between the two services. By the end of the war, Japan produced at least 90 basic aircraft types (53 navy and 37 army) and 164 variations on basic types (112 navy and 52 army), making the logisticians’ jobs that much harder.

Japanese technicians and repairmen, already too few in number to handle even a well-managed maintenance system, were scattered in weak groups so as to cover the wide variety of equipment. Identifying, segregating and issuing the multitude of parts on a timely basis to the correct user was beyond their ability. The Japanese were hard-pressed to manage normal maintenance, let alone spare men and equipment for unauthorized field expedient modifications.

Mechanics at forward airfields were not trained well enough to correct many of the factory faults that were discovered when new aircraft arrived on station. The Japanese military also failed to master the supply, maintenance and medical problems that arose once their aerial units reached tropical zones far from their main depots.

Communications were a problem as well. The navy had great difficulty in controlling its combat air patrols because of bad radios. “It seemed to us,” recalled Rear Adm. Raizo Tanaka, “…that every time a battle situation became critical our radio communications would hit a snag, causing delay in important dispatches…but it seemed to hold no lesson for us since communication failures continued to plague us throughout the war.” Maintenance of aircraft radios was so difficult, spare parts so few and reliability so bad that many frustrated pilots actually removed them from their planes to save weight.

Another limitation was that Home Island flight instructors were faced with too many students to train them effectively. The urgency of training pilots overwhelmed the curriculum. “We couldn’t watch for individual errors and take the long hours necessary to weed the faults out of a trainee,” Sakai recalled in 1943. “Hardly a day passed when fire engines and ambulances did not race down the runways, sirens shrieking, to dig one or more pilots out of the plane they had wrecked on a clumsy takeoff or landing.” The decision to press for quantity over quality meant that poorly trained fliers graduated to combat units. “We were told to rush men through,” Sakai said, “to forget the fine points, just teach them how to fly and shoot.”

By the end of 1943, the army and navy had lost about 10,000 pilots. As American Lt. Gen. George C. Kenney reported to Washington, “Japan’s originally highly trained crews were superb but they are dead.” When matched to pilot production of 5,400 army and 5,000 navy in the same period, and when one considers the expansion in units, missions, tempo and geographical separation, it is clear that Japan’s pilot strength had not increased at all. Worse, the vast majority of prewar and even 1942-43 veterans were dead or wounded, and their replacements had none of the veterans’ experience.

As the Japanese empire shrank, its air forces fell back on the logistics base. The aircraft repair system became less extended. Even so, by 1944 a growing shortage of spare parts for the older aircraft began to ground fighters and bombers. Minor battle damage to structurally weak aircraft, although repairable under better conditions, often meant that the plane never flew again.

Aviation fuel existed in sufficient quantities throughout the Japanese military into mid-1944. As early as late 1943, however, commanders began teaching pilots how to conserve fuel. When the fuel shortage finally hit, it generally had no immediate or widespread effect on combat operations, but it had an adverse effect on training programs. When aviation gasoline became scarce, army trainees flew gliders during the first month of training to save fuel. Fuel shortages started affecting combat operations in mid-1944, just when American air activity was reaching its peak.

Veteran instructors, including others on permanent limited duty and those recovering from wounds, began to leave their training duties to rejoin combat units. Many frontline pilots hated teaching anyway, especially as the number of training hours dropped and the quality of students declined. Men who had been rejected for pilot training over the previous two years were now accepted.

By 1945 Japanese planes at Clark Field on Luzon were scattered far and wide in a dispersal effort. The field’s maintenance effort had collapsed. Hundreds of aircraft sat grounded with only minor problems. For example, one aircraft might be missing a carburetor, but since no one had arranged for the salvage of a good carburetor from an aircraft missing its landing gear, both aircraft were as good as shot down.

An American intelligence officer who examined Clark after its capture reported, “It is impossible to describe the situation as a whole beyond saying that everywhere is evidence of disorganization and general shambles.” The Americans found 200 new aircraft engines at a village near Clark, most still in shipping crates. Ground crews had dispersed them far and wide in little dumps of three and four. They were hidden underneath houses, rice mills, shacks and public buildings. Huge numbers of parts such as carburetors, fuel pumps, generators and propellers were likewise scattered in fields and under houses, and also buried. Mechanics buried tools in no discernable pattern. Initial counts of aircraft in and around Clark topped 500, many of them obviously burned out, but many seemingly ready to fly.

The Japanese had not experienced the logistical challenges that the Western powers had addressed during World War I and later relearned. Japan’s politicians, generals and admirals completely misjudged the character and the duration of the war they launched in 1941. Poor aerial logistics planning, lack of foresight, a racist contempt for their enemies, a weak, shallow, narrow industrial base and an inability to appreciate supply requirements or to learn from their failures characterized their aviation effort throughout the entire war.

This article was written by John W. Whitman and originally published in the September 2006 issue of Aviation History.

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