This convoy operation, designated Operation No. 81, would end disastrously and become known as the Battle of the Bismarck Sea. Part of the plan of this operation called for reinforcement of Tuluvu with aviation material and personnel so that it could be used as a refueling base by the Japanese Army Air Force.

The 617-ton transport No. 9 Fukuei Maru set sail from Rabaul on the morning of February 17th loaded with 600 drums of aviation fuel and other material. In addition to its cargo the little ship was crowded with 120 troops including a small detachment from the 4th Air Intelligence Unit and a platoon from the 21st Airfield Battalion (Ab). Type 1 fighters of the 11th FR flew cover.

On the morning of the 18th the ship was attacked by a B-24 northeast of Cape Gloucester. Bombs landed close and machine gun fire hit the ship causing two fires to break out. The ship took refuge east of Cape Gloucester. Later it continued its voyage and landed its passengers and cargo at the village of Kalingi near Cape Gloucester on the 19th. After the attack on the 18th six fighters of the 11th FR intercepted the B-24 within sight of the airfield but the B-24 escaped into the clouds and returned to its base claiming one fighter destroyed. The fighters landed at Tuluvu at around 1500 on the 18th. They flew air patrols over Tuluvu the following morning and gave chase to yet another B-24. The B-24 claimed one fighter damaged and it also escaped. During four days of operations over Tuluvu and covering the transport during its transit to and from Rabaul the 11th FR had several encounters during which it lost two fighters destroyed and three damaged. One of the fighters reportedly crash-landed a short distance east of Cape Gloucester.

The attacks on Fukuei Maru followed a month (16 January-15 February) during which the Tuluvu Detachment recorded attacks or patrols by 42 B-24s, 17 B-17s, and 11 unidentified aircraft. Principal damage was to the runway but anti-aircraft guns were also hit. In one instance a B-24 flew just 500 meters over the airfield to drop its bombs on the runway.

Operation No. 81 got underway late on February 28th when a convoy of eight transport ships and eight destroyers left Rabaul. Forewarned by radio intelligence the Allied fighters and bombers had been rested and were waiting. Since the earlier Lae operation bomber and attack units had practiced the technique of low altitude skip bombing. A number of A-20s and B-25s had been modified with increased forward firing armament.

The convoy took the route around New Britain’s north coast. March 1st was its first full day at sea. Shortly after 1000 hours that morning an “assault plane” (this was undoubtedly a Type 99 assault plane, Ki 51, of which the 6th FD possessed a single example at this time) landed at Tuluvu with a staff officer from Rabaul on board. He stayed only a half hour and then returned to Rabaul. The exact purpose of the liaison is not known but it seems likely it was to ascertain that the airfield was fit for use as intended. During this visit fighters patrolled overhead but did not land.

That afternoon a B-24D of the 321st BS flying at 10,000 feet sighted the convoy in a position roughly 100 miles due west of Rabaul. Clouds and rain were prevalent and the convoy proceeded safely that day. The B-24 sighted three Japanese fighters in the area but was not attacked.

On March 2nd the weather continued less than favorable but several attack missions were launched. Some were supported by long-range P-38 fighters. Attacks that day took place north and west of Cape Gloucester.

In several waves 32 P-38s, 28 B-17s and two B-24s operated close to Cape Gloucester in carrying out their attacks during the late morning and early afternoon. Fifteen Japanese army fighters intercepted these aircraft. P-38s jumped three fighters and claimed two OSCARS destroyed south of Cape Gloucester. The bombing attacks sank one cargo ship. The air combats were fought among layers of clouds and were generally inconclusive. The Japanese claimed two B-17s shot down (available Japanese reports conflict as to whether these were claimed as certain or uncertain victories) but in fact inflicted only minor damage on four of the bombers. In addition to the claims by P-38s the bombers claimed several sure and probable victories. The Japanese admitted no losses in combat. The loss of one fighter that day was attributed to accident. During the day three Japanese fighters landed at Tuluvu, refueled, and took off again. Forces from Tuluvu were later detailed to engage in rescue operations for survivors of the ship lost.

The morning of March 3rd found the convoy in the Huon Gulf sailing in beautiful weather with several hours steaming separating it from its goal. Nearly three-dozen navy Zero fighters were over the convoy or about to arrive on station when trouble began. About a hundred American and Australian aircraft were marshalling to carry out a carefully coordinated and well-practiced attack using both new low altitude tactics and conventional medium altitude attacks. In a matter of minutes all the transports were hit and left sinking or disabled, as were four destroyers. Follow-up attacks completed their destruction. Land-based Zero fighters from the aircraft carrier Zuiho and Air Groups 204 and 253 blunted the attack by escorted B-17s shooting down one B-17 and three P-38s. By the time they turned their attention to the low level attackers the convoy had been decimated. In small formations and individually Zeros attacked some of the B-25s, A-20s and Beaufighters and their escorting fighters. They damaged a few but their attacks were largely ineffectual. Eight of the thirty-three intercepting Zeros were lost. Three were shot down out-right with pilots killed and five crashed.

Many additional combats took place later that day and the next as Allied planes returned to deliver the coup de gras to disabled ships and to strafe survivors in life-boats or clinging to floating wreckage. Several Japanese army fighters were lost or damaged that afternoon and additional losses were suffered on the 4th including Maj. Mitsugu Sawada newly appointed commander of the 1st FR.

After the disaster in the Battle of the Bismarck Sea the strategic importance of Tuluvu and western New Britain greatly increased. Following a final destroyer transport mission to Finschhafen at the end of March, Tuluvu became the point closest to Lae that Japanese destroyers would operate. MLCs and other small boats took on an increased importance in Japanese reinforcement and re-supply efforts. Western New Britain became important as a barge staging area and hideout for small boats prior to crossing the straights to New Guinea (usually between Busching on New Britain and Cape Arndt on New Guinea). The number of landing barges engaged in Lae re-supply runs was eventually built up to over forty but it was never sufficient even when supplemented by the efforts of submarines (plans to increase the Lae MLCs to 60 in June, 90 in July and 210 in August 1943 never materialized). In June about ninety fishing boats with civilian crews from Japan arrived in the Southeast Area to aid local transportation. These small ships made a number of runs to Tuluvu but MLCs remained the primary mode of coastal transportation.

In the weeks surrounding the Battle of the Bismarck Sea (16 February-15 March) 50 B-17s, 27 B-24s, and 9 unidentified aircraft reportedly over-flew Tuluvu. One man was killed and one cannon damaged in their attacks.

Despite gradual improvements, including completion of a hanger and extension of dispersal tracks, the runway at Tuluvu was a constant source of trouble. In addition to suffering repeated bomb damage it was poorly drained and at times was unserviceable due to flooding. Eventually the decision was made to build an entirely new runway east of the original one. The first airstrip would be available to house a fighter squadron and as an emergency field for other types. The second was to be a more ambitious project capable of supporting a larger number of aircraft including medium bombers and transports.

Many ground units transited through Tuluvu after spending a brief sojourn lasting days or weeks. There was a slow build up of permanent ground units and air service units in the region. Successful reinforcement operations by two destroyers each arrived on March 19th, April 11th, and April 13th. On June 4th the single destroyer Amagiri made a successful run to Cape Gloucester. Army fighters covered these runs. Barges and small boats generally operated without fighter cover relying on darkness and coastal hideouts to avoid air attack.

After the Bismarck Sea action little reliable information about Japanese air operations at Tuluvu is available in March and April. Allied reconnaissance sighted a single fighter there in mid-March. On April 14th two aircraft identified as fighters were seen on the west side of the airfield and strafed by an Allied bomber. More than thirty barrels of aviation fuel were dispensed during each of these months, enough to refuel several aircraft and this probably occurred, but it is possible some of it was provided for boat or motor transport purposes.