INTERROGATION NAV NO. 71
USSBS NO. 360

JAPANESE NAVAL LAND-BASED AIR OPERATIONS IN WESTERN NEW GUINEA

TOKYO 12 NOVEMBER 1945

Interrogation of: Captain KOMOTO, H., IJN ; Flight Leader of 753 Air Corps from February 1943 to Tune 1943, attached to Staff of 23rd Air Flotilla from June 1943 to July 1944.

Interrogated by: Commander T. H. MOORER, U.S.N.

SUMMARY

During 1943 the 23rd Air Flotilla with headquarters at KENDARI conducted search and attack missions on a minor scale in the area southwest of NEW GUINEA. After the capture of the ADMIRALTY ISLANDS in March 1944, the headquarters of the 23rd Air Flotilla was moved to DAVAO in order to counter expected carrier attacks on the PHILIPPINES and PALAU. When it became evident that the Allied move from the south was to continue along the North NEW GUINEA Coast the 23rd Air Flotilla was moved to SORONG (April 1944) and was heavily reinforced in order to carry out the assigned mission of search and attack against Allied invasion forces. On 11 June 1944, naval air operations in Western NEW GUINEA were cancelled and all aircraft moved to PALAU in order to execute the "AGO" Plan for the defence of the MARIANAS. At PALAU the air strength was almost totally destroyed and the 23rd Air Flotilla ceased to be an offensive unit.

TRANSCRIPT

Q. When was the 23rd Air Flotilla established at KENDARI?
A. In February 1942.

Q. Where was the headquarters of the 13th Air Fleet?
A. About September 1943, the 13th Air Fleet moved from SOERABAJA to PENANG and then to SINGAPORE, then returned back to SOERABAJA in the middle of February 1944, then moved to MANILA around August or September 1944.

Q. Was the 23rd Air Flotilla the only land-based Naval Air Force in the Western NEW GUINEA Area?
A. Yes, but the total number of aircraft assigned varied from time to time.

Q. What forces were available to the 23rd Air Flotilla prior to the Allied invasion of the ADMIRALTY ISLANDS?
A. The 23rd Air Flotilla was composed of one 36 plane fighter squadron with 12 reserves (in December 1943 this squadron was moved to TRUK) and one 36 plane twin-engine attack squadron with 12 reserves (in January 1944 this squadron moved to KWAJALEIN). The above squadrons were replaced by one 36 plane fighter squadron and one 12 plane reconnaissance squadron on dates indicated above. From December to March the reconnaissance squadron was reinforced by 9 additional planes (BETTYS).

Q. Was this the maximum number of planes available to the 23rd Air Flotilla?
A. Yes, until May 1944 when the force was increased.

Q. What was the mission of the 23rd Air Flotilla prior to March 1944?
A. Prior to that time the 23rd Air Flotilla was responsible for the area southwest of the NEW GUINEA Coast. The northeast coast was the responsibility of the Army. The specific missions were: (1) Maintenance of air bases, (2) protection of CELEBES Area against air attack, (3) convoy escort, (4) search of sea area between NEW GUINEA, AUSTRALIA and TIMOR and (5) monthly attacks against DARWIN and MERAUKE.

Q. Indicate bases from which the 23rd Air Flotilla operated prior to loss of ADMIRALTY ISLANDS.
A. KENDARI, KOEPANG, AMBON, KAI Island, BALIKPAPAN, MAKASSAR, SORONG, NABIRE, SOEMBA and BABO.

Q. Were aircraft stationed at all bases mentioned above?
A. Yes.

Q. Why was it necessary to base fighters at BALIKPAPAN and MAKASSAR?
A. To protect against possible B-24 attacks from DARWIN.

Q. What was the mission of the KOEPANG and KAI detachments?
A. The detachments at KAI and KOEPANG searched shipping lanes in TORRES Strait and DARWIN Area.

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Q. During the operations prior to the capture of the ADMIRALTY ISLANDS, did the Japanese suffer any serious losses?
A. No serious losses were suffered from operations. However, in October 1943 and continuing through the winter the best pilots and planes were gradually transferred to the 25th Air Flotilla at RABAUL. As a result, in the winter of 1943 and 1944 the 23rd Air Flotilla reached its lowest strength. These pilots were replaced with battle fatigue pilots from RABAUL, thus decreasing the efficiency of the 23rd Air Flotilla. Replacement aircraft were received direct from JAPAN.

Q. At the end of March after the loss of the ADMIRALTIES, what change in directives did the 23rd Air Flotilla receive?
A. After the capture of the ADMIRALTY ISLANDS, the headquarters of the 23rd Air Flotilla was moved to DAVAO, since it was expected that your carrier Task Force would operate against PALAU and MINDANAO. We were instructed that, in order to conserve strength, not to attack in the area southwest of NEW GUINEA, but merely to protect and maintain the air bases. We were also instructed to establish a patrol along the north coast of NEW GUINEA extending to the ADMIRALTY ISLANDS. These patrols were conducted first from WAKDE, then from BIAK, and finally from SORONG. In order to carry out these orders aircraft were redistributed. Bombers were moved to DAVAO to meet your expected carrier attacks and search planes were moved to north coast of NEW GUINEA.

Q. What type of aircraft was used for the patrol?
A. Army type aircraft manned by Navy crew as well as regular Navy search planes.

Q. What was the specific mission of this patrol?
A. To search for and report your invasion forces.

Q. Were many of these aircraft lost?
A. Very few.

Q. What action was to be taken if a search plane reported an Allied Task Force?
A. Navy aircraft were to be staged through SORONG from DAVAO and PALAU. Army aircraft were also to assist in the attacks.

Q. What was the eastward limit to which the 23rd Air Flotilla operated?
A. The ADMIRALTY ISLANDS.

Q. What liaison was maintained between the 13th Air Fleet and the 11th Air Fleet which was at RABAUL?
A. The liaison was maintained by personal visits between staffs. There was an exchange of intelligence information but there were no joint operations.

Q. Why were the headquarters of the 23rd Air Flotilla moved from DAVAO to SORONG?
A. The headquarters were moved about 13 April 1944 because at that time reconnaissance revealed that there was no immediate threat to MINDANAO and PALAU as previously thought, but that the Allied forces were massing in Eastern NEW GUINEA preparatory to a possible invasion of HOLLANDIA. Since this also meant that you would not by-pass NEW GUINEA but intended to invade BIAK and then continue up the NEW GUINEA Coast to the PHILIPPINES, the force of the 23rd Air Flotilla was increased to 180 aircraft by moving air units from MALAYA, JAPAN and TRUK. The squadron from JAPAN had originally participated in the defense of KWAJALEIN, but suffered such heavy losses that it had to return to JAPAN for reforming.

Q. After the 23rd Air Flotilla was built up to a strength of 180 aircraft, who had operational control?
A. At this time operational control was changed from the 13th Air Fleet to the First Air Fleet which was in turn directly controlled by the Combined Fleet Headquarters. The 13th Air Fleet with a small force at KENDARI continued minor operations southwest of NEW GUINEA.

Q. After the 23rd Air Flotilla was moved to SORONG and placed under the control of the First Air Fleet, what changes in operational directives were received?
A. Our new mission was to search for the enemy Task Force approaching the NEW GUINEA base and if sighted, attack and destroy it. Also conduct night harassing attacks with small number of planes. The air force at PALAU was to assist when possible.

Q. During these operations what cooperation was received from the Japanese Army?
A. The Fourth Air Army with headquarters at SAMATE assisted in patrol and offensive operations against your Task Force. The responsibility of attacking the invasion forces belonged to the Navy but the Army gave support when possible. In May 1944, about 70 Army planes were sent from MANILA and placed under operational control of the 23rd Air Flotilla at SORONG, to assist in search and attacks against Allied invasion force. These planes were in addition to Army forces already in the area west of HOLLANDIA.

Q. Upon whose authority were Army planes placed under control of the Navy?
A. The Supreme Headquarters issued the orders through the Commander-in-Chief of the Combined Fleet.

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Q. When did you know that HOLLANDIA was to be invaded?
A. The invasion of HOLLANDIA came as a complete surprise. The aircraft available for searches were so few it was only possible to make a dawn patrol; and consequently the HOLLANDIA force was not seen until after it had anchored. After you invaded HOLLANDIA, as I said before, it was obvious that the next movement would be up to BIAK, along the north coast of NEW GUINEA instead of PALAU and MINDANAO as originally thought.

Q. How do you account for the general lack of Japanese air activity during the HOLLANDIA-BIAK operation?
A. Speaking for the Navy, the main reason for the lack of air activity in NEW GUINEA was because of small forces available and extremely difficult experience with maintenance.

Q. Does the same thing apply to the Army air forces?
A. The Army had ample aircraft but they also had terrific difficulty with maintenance. In addition, a great number of Army aircraft were destroyed on the ground by the Allied air forces.

Q. Was this very poor maintenance due to lack of supply or trained personnel, or both?
A. Material and personnel were not entirely the best. The best was previously sent to RABAUL.

Q. Were operations ever interfered with by the lack of fuel?
A. No, the aircraft were so few that plenty of fuel was available.

Q. Was this shortage of supplies due mainly to the loss of convoys?
A. The loss of convoys was not the total blame; but rather the lack of production capacity at home. An effort was made to supply spare parts by air. This, too, was unsuccessful as the spares did not exist. This lack of spare parts plus poor maintenance was a major cause of aircraft losses because aircraft could not be shifted from field to field to escape your attacks.

Q. At what time did you learn of the approach of the invasion force to BIAK?
A. Twenty four hours before the landing, the invasion force was detected by search planes.

Q. Why, after the invasion force was located, did the Japanese air force delay their attack?
A. The delay in attack was due to the fact that aircraft had to be staged from DAVAO, and there was considerable difficulty experienced in attempting to rendezvous forces from different fields in order to make a mass attack.

Q. Describe the KON Plan for the reinforcement of BIAK?
A. The purpose of the KON Plan was to reinforce BIAK with one brigade of 5,000 men. Three attempts were made to execute this plan. The first landing was to take place on 3 June. The force involved consisted of one battleship (MUSASHI), four cruisers, and six destroyers. They sortied from DAVAO for BIAK, and on 2 June were discovered by an enemy patrol plane. Anticipating a heavy attack they turned back. The battleship and two cruisers which were not carrying troops put into BATJAN, and the six destroyers and two cruisers which were loaded with troops put into SORONG. The next attempt was planned for 8 June. A maximum number of troops were loaded aboard six destroyers and sailed for BIAK. The force was subjected to a heavy air attack on the afternoon of 7 June and one destroyer was sunk. They continued on and at 2300 they were engaged by Allied surface vessels. The Japanese ships suffered no sinkings but some damage and were forced to return to BATJAN without landing the troops. The third attempt was planned for the 15th of June. The force was to be approximately the same as that in the first attempt and the intention was to land the troops at all costs, regardless of losses. However, the operation was suddenly cancelled, because on 11 June orders were received placing in effect the AGO Plan which involved the defense of the MARIANAS. All surface vessels were immediately ordered north.

Q. What effect did this change in plans have on the 23rd Air Flotilla?
A. All Navy aircraft in the NEW GUINEA Area were ordered to PALAU without delay and no further defense of NEW GUINEA was attempted by the naval air forces.

Q. What part did the 23rd Air Flotilla aircraft take in defense of the MARIANAS?
A. I do not know exactly since they were no longer controlled by the 23rd Air Flotilla Headquarters. The remaining aircraft were nearly all destroyed during the defense of PALAU. A few escaped to DAVAO. After the defense of NEW GUINEA was abandoned, the 23rd Air Flotilla moved to AMBON (28 June) and from there to the original base at KENDARI around the end of July. Army air forces were finally withdrawn from the NEW GUINEA Area and based at LOLOBATA and MENADO. After that time the Army aircraft were used to protect convoys in the CELEBES and were controlled from headquarters in JAVA.

Q. During the time the Army planes were based along the north coast of NEW GUINEA, what was their mission?
A. The first mission of the Army air forces was to attack your bases in Eastern NEW GUINEA. The other mission was to escort transports supplying NEW GUINEA garrisons. Just before the capture of BIAK the Army air force retreated to LOLOBATA and attacked separately from the Navy. They used SAMATE, NOEMFOOR and RANSIKI as advanced bases.

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Q. Why were so many Army aircraft caught on the ground at HOLLANDIA?
A. They were surprised because they never expected your air force to attack in such strength. Also many planes were grounded because of no spares and could not be moved.

Q. In July 1944 during the BIAK Operation, what planes made the night attacks?
A. Navy planes (BETTYS).

Q. Were there times when the Army and Navy planes used the same fields at the same time?
A. Only SORONG.

Q. That was after the capture of BIAK?
A. Immediately before the capture of BIAK and after.

Q. During the BIAK Operation, were there any aircraft in NEW GUINEA other than those in SORONG?
A. The Army air force used SAMATE, NOFMFOOR and RANSIKI, as staging fields but the Army air force was very small.

Q. Were the Japanese successful in the use of camouflage?
A. During this campaign we employed camouflage and revetments and dispersal; but if sufficient warning was available, aircraft were withdrawn to the west.

Q. At what time during this period did the Japanese cease supplying the Western NEW GUINEA Area?
A. After June 11, 1944, no further attempt was made to defend NEW GUINEA by air.

Q. After the Allied air force began to operate in Western NEW GUINEA, what methods were used to bring supplies into NEW GUINEA?
A. Supplies were furnished by sea truck and small landing craft.

Q. During the HOLLANDIA-BIAK Operations how did the number of Japanese Army planes in this area compare with the Navy planes?
A. After the loss of BIAK, the Navy had a larger air force then the Army.

Q. What services were responsible for establishing fields along the northeast coast of NEW GUINEA -- Army or Navy?
A. BIAK was both Army and Navy; NOEMFOOR, MANOKWARI, LOLOBATA, SAMATE, SORONG -- Navy; NABIRE -- Navy; and HOLLANDIA -- Army; WAKDE -- Navy; all east of HOLLANDIA were Army. WAKDE, after March 1944, became Army.

Q. Why did the Japanese delay as long as they did before developing fields on BIAK?
A. The construction of fields at BIAK and also other fields in Western NEW GUINEA Area were delayed by the lack of material and equipment.

Q. Did the bombing of the air fields by the Allied forces seriously interfere with Japanese operations?
A. Yes, prior to and during the BIAK Campaign the only usable fields available were BABO and SORONG. SORONG was usable until the end of the campaign.

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