Operation Vengeance - Interception Mission

Interception Mission

To avoid detection by radar and Japanese personnel stationed in the Solomon Islands along a straight-line distance of about 400 miles (640 km) between U.S. forces and Bougainville, the mission entailed an over-water flight south and west of the Solomons. This roundabout approach flight was plotted and measured to be about 600 miles (970 km). The fighters would therefore travel 600 miles out to the target and 400 miles back. The 1,000-mile flight, with extra fuel allotted for combat, was beyond the range of the F4F Wildcat and F4U Corsair fighters then available to Navy and Marine squadrons based on Guadalcanal. The mission was instead assigned to the 339th Fighter Squadron, 347th Fighter Group, whose P-38G aircraft, equipped with drop tanks, had the range to intercept and engage.

In preparation for the mission, Marine Corps Lt. Col. Luther S. Moore had the P-38s fitted with a Navy ship's compass to aid in navigation at the request of Major John W. Mitchell, commanding the 339th. The fighters each mounted a standard armament of a 20 mm cannon and four 50-caliber (12.7 mm) machine guns, and were equipped to carry two 165-US-gallon (620 L) drop tanks under their wings. A limited supply of 330-US-gallon (1,200 L) tanks was flown up from New Guinea, sufficient to provide each Lightning with one large tank to replace one of the small tanks. Despite the difference in size, the tanks were located close enough to the aircraft's center of gravity to avoid any performance problems.

Eighteen P-38s were tasked for the mission. One flight of four was designated as the "killer" flight while the remainder, which included two spares, would climb to 18,000 feet (5,500 m) to act as "top cover" for the expected reaction by Japanese fighters based at Kahili. A flight plan was prepared by the Command Operations Officer, Marine Major John Condon, but was discarded for one prepared by Mitchell. He calculated an intercept time of 09:35, based on the itinerary, to catch the bombers descending over Bougainville, ten minutes before landing at Ballale airfield. He worked backwards from that time and drew four precisely-calculated legs, with a fifth leg added if Yamamoto did not take the most direct route. In addition to heading out over the Coral Sea, the 339th would "wave-hop" all the way to Bougainville at altitudes no greater than 50 feet (15 m), maintaining radio silence en route.

Although the 339th Fighter Squadron officially carried out the mission, ten of the eighteen pilots were drawn from the other two squadrons of the 347th Group. The Commander Air Solomons, Rear Admiral Marc A. Mitscher, selected the four pilots of the designated "killer" flight: Capt. Thomas G. Lanphier, Jr., 1st Lt. Rex T. Barber, 1st Lt. James D. McLanahan, and 1st Lt. Joseph F. Moore. A thorough, detailed briefing included a cover story for the source of the intelligence stating that a coastwatcher had spotted an important high-ranking officer boarding an aircraft at Rabaul, but the pilots were not specifically briefed that their target was Admiral Yamamoto.

The specially-fitted P-38s took off from Guadalcanal's Fighter Two airstrip beginning at 07:25. The date, April 18, was the first anniversary of the Doolittle Raid. Two of the Lightnings assigned to the killer flight dropped out of the mission at the start, one with a tire flattened during takeoff (McLanahan) and the second when its drop tanks would not feed fuel to the engines (Moore).

In Rabaul, despite urgings by local commanders to cancel the trip for fear of ambush, Yamamoto's airplanes took off as scheduled for the 315 miles (507 km) trip. They climbed to 6,500 feet (2,000 m), with their fighter escort at their 4 o'clock position and 1,500 feet (460 m) higher, split into two V-formations of three planes.

Mitchell's flight of four led the squadron at low altitude, with the killer flight, now consisting of Lanphier, Barber, and spares 1st Lt. Besby F. Holmes and 1st Lt. Raymond K. Hine, immediately behind. Mitchell, fighting off drowsiness, navigated by flight plan and dead reckoning. This proved to be the longest fighter-intercept mission of the war and was so skillfully executed by Mitchell that his force arrived at the intercept point one minute early, at 09:34, just as Yamamoto's aircraft descended into view in a light haze. The P-38s jettisoned the auxiliary tanks, turned to the right to parallel the bombers, and began a full power climb to intercept them.

The tanks on Holmes's P-38 did not detach and his element turned back toward the sea. Mitchell radioed Lanphier and Barber to engage, and they climbed toward the eight aircraft. The nearest escort fighters dropped their own tanks and dived toward the pair of P-38s. Lanphier, in a sound tactical move, immediately turned head-on and climbed towards the escorts while Barber chased the diving bomber transports. Barber banked steeply to turn in behind the bombers and momentarily lost sight of them, but when he regained contact, he was immediately behind one and began firing into its right engine, rear fuselage, and empennage. When Barber hit its left engine, the bomber began to trail heavy black smoke. The Betty rolled violently to the left and Barber narrowly avoided a mid-air collision. Looking back, he saw a column of black smoke and assumed the Betty had crashed into the jungle. Barber headed towards the coast at treetop level, searching for the second bomber, not knowing which one carried the targeted high-ranking officer.

Barber spotted the second bomber, carrying Chief of Staff Vice Admiral Matome Ugaki and part of Yamamoto's staff, low over the water off Moila Point, trying to evade an attack by Holmes, whose wing tanks had finally come off. Holmes damaged the right engine of the Betty, which emitted a white vapor trail, but his closure speed carried him and his wingman Hine past the damaged bomber. Barber attacked the crippled bomber and his bullet strikes caused it to shed metal debris that damaged his own aircraft. The bomber descended and crash-landed in the water. Ugaki and two others survived the crash and were later rescued. Barber, Holmes and Hine were attacked by Zeros, Barber's P-38 receiving 140 hits. Holmes and Barber each claimed a Zero shot down during this melee, although Japanese records show that no Zeros were lost. The top cover briefly engaged reacting Zeros without making any kills. Mitchell observed the column of smoke from Yamamoto's crashed bomber. Hine's P-38 had disappeared by this point, presumably crashed into the water. Running close to minimum fuel levels for return to base, the P-38s broke off contact, with Holmes so short of fuel that he was forced to land in the Russell Islands. Hine was the only pilot who did not return.

As he approached Henderson Field, Lanphier radioed the fighter director on Guadalcanal that "That son of a bitch will not be dictating any peace terms in the White House", breaching security. Immediately on landing (his plane was so short on fuel that one engine quit during landing rollout) he put in a claim for shooting down the bomber, relating that when he turned to engage the escort Zeroes, he shot the wing off one, flipped upside down as he circled back towards the bombers, and saw the lead bomber turning a circle below him. He stated he came out of his turn at a right angle to the circling bomber and fired, blowing off its right wing. He reported that he witnessed Barber shoot down another bomber which also crashed in the jungle. Holmes claimed the Betty that crashed into the water, and it was assumed that three bombers had been downed. The fifteen surviving pilots were not debriefed after the mission because a formal interrogation procedure did not exist on Guadalcanal at that time, and it was never officially established that Lanphier's claim was not witnessed.