Formosa Air Battle


The Formosa Air Battle, 12–16 October 1944, was a series of large-scale aerial engagements between carrier air groups of the United States Navy Fast Carrier Task Force and Japanese land-based air forces of the Imperial Japanese Navy and Imperial Japanese Army. The battle consisted of American air raids against Japanese military installations on Taiwan during the day and Japanese air attacks at night against American ships. Japanese losses exceeded 300 planes destroyed in the air, while American losses amounted to fewer than 100 aircraft destroyed and two cruisers damaged. This outcome effectively deprived the Japanese Navy's Combined Fleet of air cover for future operations, which proved decisive during the Battle of Leyte Gulf later in October.

Background

Japanese strategic plans for a decisive battle with the U.S. fleet were already established by September 1944. Anticipating the various options open to American landing forces, the Japanese operational order, code named Sho, envisioned four scenarios numbered from one to four. Sho-1 , 2 , 3 , and 4 were meant to defend respectively the Philippines, Formosa and Okinawa, the Japanese homeland, and Hokkaido plus the Kuril Islands.
Due to Japan's losses during the Battle of the Philippine Sea, the core of its air power for operation Sho was land-based. The plan also broke with IJN tradition by assigning overriding importance to sinking U.S. supply vessels rather than U.S. warships. To restore morale, the Commander-in-Chief of the Combined Fleet Admiral Soemu Toyoda flew out to the front in early October to rally the troops behind Sho.
The Japanese navy had formed a special air unit called the T Attack Force, the "T" short for "typhoon", to experiment with rough-weather training. This strategy, along with night operations and submarine warfare, was meant to compensate for Japan's smaller fleet compared to that of the United States by flying missions in weather conditions that the Americans were not trained for. However, like other Japanese units at the time, the T Attack Force suffered from a shortage of pilots, even after recruiting green fliers directly from the army. Their inexperience, compounded by carrying out missions at night, would later lead to poor performance and exaggerated kill counts during the actual battle.
By 10 October Toyoda's tour of the front was complete. He intended to depart from Formosa for Japan that same day but was forced to change his plans when Vice Admiral Marc Mitscher's Fast Carrier Task Force suddenly appeared to the north, launching strikes against the Ryukyu Islands. Toyoda could not risk a return trip home through a concentrated enemy carrier force that now embarked more than 1,000 aircraft, especially not after previous Combined Fleet commanders had been lost during aerial engagements. As a result, he was grounded far from Combined Fleet headquarters at a decisive moment. Out of position and with inadequate lines of communication, the response to such overwhelming enemy air power was left to Toyoda's Chief of Staff, Vice Admiral Ryūnosuke Kusaka.
Kusaka correctly saw these strikes as a precursor to U.S. troop landings, in part due to Imperial Navy intelligence collected over the previous week. Because he was still unsure exactly where enemy forces would land, he chose to execute the air component of Sho-1 or Sho-2the planned defense of the Philippines or Formosa, respectivelyon the morning of 10October. Sho was a complex plan involving multiple naval surface forces sortieing from bases as far away as Singapore and Japan. It would take these warships time to maneuver into position for a concerted attack. Rather than waiting for the arrival of the fleet for a combination of sea and air power, Kusaka ordered the air forces reserved for Sho to engage the enemy at once. He reinforced this order by implementing Sho-2 in full on the morning of 12October.
Over 1,800 aircraft were allocated for Sho in total, but they were widely dispersed across the four operation regions. About one third of them were not battle-ready due to casualties and a lack of parts or trained pilots. When the fighting began, Vice Admiral Shigeru Fukudome had approximately 700 planes ready in Formosa and Kyushu. 100 or so aircraft in the Seto Inland Sea was later added to his command. Over the next four days, an additional 690 or so planes flew in from bases in Japan and China.
Although this represented a huge number of available aircraft, the Imperial Japanese Navy Air Service was still recovering from losses suffered at the Battle of the Philippine Sea in June. While units were largely reconstituted in terms of quantity by this time, pilot quality was in clear decline. Moreover, though the overall number of planes committed to battle by 12October dwarfed any force that Japan had previously fielded in the air, the U.S. Navy's Fast Carrier Force was capable of committing a much larger, significantly better-trained force.

Order of battle

;
  • Imperial Japanese Navy Air Service: over 1,200 fighters/bombers allocated for all four regions of operation Sho
  • * 1st Air Fleet based in Manila, Philippines: 350 land-based planes
  • * 2nd Air Fleet based in Kyushu and Takao, Taiwan: 510 land-based planes
  • * 3rd Air Fleet: 300 land-based planes plus 100 diverted from carrier divisions
  • * 12th Air Fleet based in Hokkaido and the Kuril Islands: fewer than 100 planes, for emergencies
  • * 13th Air Fleet based in Malay and the Dutch East Indies: fewer than 100 planes, for emergencies
;
  • Imperial Japanese Army Air Service: approximately 600 planes allocated for all Sho regions
  • * 4th Air Army based in Manila, Philippines: about 200 planes
  • * Formosa Army based in Taihoku and Takao: about 200 planes
  • * Homeland training forces: about 200 planes
Approximately one-third of the airframes allocated were unavailable due to casualties and a lack of parts or trained pilots. 720 planes were placed under Fukudome's unified command when the battle began, with 100 planes from the Seto Inland Sea added later on. The 330 based in Formosa were able to defend immediately. About 350 were still based in Kyushu and participated in attacks against the American fleet over water. Some 690 additional planes flew in from bases in Japan and China over the next four days.
;
  • Third Fleet
  • * Task Force 38 : 17 aircraft carriers, 6 battleships, 4 heavy cruisers, 11 light cruisers, 57 destroyers
  • ** Task Group 38.1 : USS Cowpens, USS Hornet, USS Monterey, USS Wasp
  • ** Task Group 38.2 : USS Bunker Hill, USS Cabot, USS Hancock, USS Independence, USS Intrepid
  • ** Task Group 38.3 : USS Essex, USS Langley, USS Lexington, USS Princeton
  • ** Task Group 38.4 : USS Belleau Wood,, USS Franklin, USS San Jacinto
; United States Army Air Forces
On 9October, a Japanese patrol plane was lost to the east of Okinawa. On 10October, American forces conducted an air raid over the islands. Throughout the day and night of 11October, radar-equipped Japanese reconnaissance aircraft sighted various task groups of the Third Fleet, giving area commanders on Formosa and in the Philippines early warning. Knowing that dawn strikes on 12October were imminent, ground forces were placed on alert and aircraft were readied for early morning intercept. The Japanese forces on Formosa positioned their fighter planes in two groups, one covering Taihoku and the other covering Takao. In Kyushu, the T Attack Force prepared for night missions while other air units planned a large formation attack against the American carriers.
Combat experience of U.S. carrier air groups during the battle depended to a considerable degree upon disposition of their task group and assigned strike targets. On the morning of 12October, the four task groups of the Fast Carrier Task Force were strung out roughly from northwest to southeast. Task Group 38.2, as the northernmost group, was assigned the northern third of Formosa. Task Group 38.3 was next in line and assigned the central portion of the island. Finally, Task Groups 38.1 and 38.4 were jointly assigned southern Formosa.

12 October

All four task groups completed launch of predawn fighter sweeps by around 06:00 hours. Because the Japanese were on alert, Grumman F6F Hellcat fighters from all four groups were intercepted by enemy aircraft and moderate to intense anti-aircraft fire was universally reported. Air-to-air engagements were fiercest over northern and central Formosa, where aircraft from Rear Admiral Gerald F. Bogan's TG38.2 and Rear Admiral Frederick C. Sherman's TG38.3 operated. Sherman's and claimed almost 50 enemy aircraft shot down between them. Bogan's task group contained three Essex-class carriers, and. Intrepid and Bunker Hill claimed over 50 Japanese aircraft destroyed, making the combined claims for the two groups around 100. The Japanese lost 17 of their 50 operational Formosa-based fighters, according to survivor Kazuo Odachi. Many of Japan's more experienced pilots were killed during the first wave of American air raid.
American carrier air groups had suffered minimal personnel losses with nine U.S. aircraft shot down with three pilots subsequently recovered by nearby ships or submarines. These lopsided results were in part due to a lack of experience among Japanese pilots. IJAAS fighters stationed to the north of the Philippines were still in training. The bulk of enemy fighter aircraft reported by U.S. aviators were Japanese Army types, primarily the Nakajima Ki-44, Kawasaki Ki-61 and Nakajima Ki-43 models. Even though there were some experienced Japanese naval aviators operating at this time, IJNAS Mitsubishi A6M Zero fighter units reconstituted after the Battle of the Philippine Sea were still learning to work together and did not execute the kind of section or division flying that yielded tactical advantage. In addition, Japanese commander Shigeru Fukudome observed that while planes in his units caught fire almost immediately upon receiving damage, American fighters were less likely to ignite.
Though the day's remaining carrier strikes by Hellcat fighters, Curtiss SB2C Helldiver dive bombers, and Grumman TBF Avenger torpedo bombers did significant damage to military installations on Formosa, they failed to completely neutralize Japanese air power based on the island. Many surviving structures would be destroyed by B-29 raids during the later days of the battle, however.
The only effective Japanese counterattack to develop against TF38 came from the home islands of Japan. A hundred or so aircraft from Kyushu attacked the task force during day time on the 12th, reportedly damaging two carriers. Hundreds more would sortie out on the 14th and 15th but fail to sight the American fleet again. Meanwhile, the T Attack Force trained for all-weather and night operations flew south to execute Japan's first large-scale radar assisted nighttime aerial torpedo attack. The results were lackluster. U.S. Navy ships made smoke for cover and engaged in radical maneuvering to keep enemies astern as Japanese aircraft dropped flares to illuminate their targets. Eight Japanese aircraft were shot down by ships' guns during the night, and three Mitsubishi G4M "Betty" bombers were claimed by night fighters from the. suffered damage from friendly fire, but no damage from enemy aircraft was incurred.