North Field

North Field ©Bill Webster

IN 1945 NORTH FIELD (TINIAN ISLAND) WAS THE LARGEST AIRPORT IN THE WORLD. IT WAS INFAMOUSLY THE BASE FOR THE ATOMIC BOMBING RAIDS ON HIROSHIMA AND NAGASAKI.

With the completion of its fourth runway in May 1945, North Field (Tinian) became the largest airport in the world. Its four 8500 ft. long runways supported 265 B-29s, their taxiways, hardstands and ground crews with base facilities and operations that maintained, repaired and serviced the B-29s. North Field based many of the conventional and incendiary bombing raids on Japanese cities and military installations, including the devastating firebombing of Tokyo in March and May 1945. It was the base for Operation Starvation, the shipping blockade of the Japanese Empire by B-29-dropped Navy mines in Japanese harbors and sea channels. North Field was infamously the base for the atomic bombing raids on Hiroshima and Nagasaki in August 1945.

313th Bomb Wing

The airfield and its USAAF Bomb Groups were assigned to the 313th Bomb Wing, under Brig. General John H. Davies. Operating from North Field were the

• 6th Bomb Group (Circle R)
• 9th Bomb Group (Circle X)
• 504th Bomb Group (Circle E)
• 505th Bomb Group (Circle W)
• 509th Composite Group (Circle Arrow) – atomic bomb group
• 5th Photographic Reconnaissance Squadron

Each of the four Marianas Islands USAAF airfields (North Field and West Field on Tinian, Isley Field on Saipan and Northwest Field on Guam) was assigned to a different Bomb Wing. The four wings comprised the 21st Bomber Command of the 20th Air Force headquartered at Guam.  [See Wing Organizations]

Runway and Hardstand Assignments

6 BG hardstands

The four parallel runways were oriented East-West and lettered “ A” (Able),” B” (Baker),” C” (Charlie) and “D” (Dog) from north to south. Each Bomb Group was given runway and hardstand area assignments:

• 6th Bomb Group: Runway D with hardstands south-side of D
• 9th Bomb Group: Runway C with hardstands between C and D
• 504th Bomb Group: Runway B with hardstands between B and C
• 505th Bomb Group: Runway A with hardstands on the northeast side of A
• 509th Composite Group: Runway A with hardstands (at time of atomic bombing) on the northwest side of A. 

Each B-29 was assigned a specific hardstand where its ground crew could set up simple quarters and store spare parts.  Each Bomb Group had its own armorers and refuelers who loaded each missioned B-29 with ordinance and fuel prior to take-off.

THE SUPPLY NEEDS OF NORTH FIELD WERE ENORMOUS. EACH B-29 TOOK-OFF WITH 25-30 TONS OF ORDINANCE AND FUEL EACH MISSION.

The supply needs of North Field were enormous. Each B-29 took-off with 25-30 tons of ordinance and fuel each mission. Multiple and maximum effort missions often involved over 100 planes from North Field per day. The four lane divided highway (Broadway) linking the supply depots and harbor with North Field were continuously busy with supply trucks.

B-29 armorer © Irv Winkler

509th Composite Group – Atomic Bombs

The top secret 509th Composite Group was assigned to the 313th Wing and North Field in May 1945, having prior completed secret training at Wendover Army Airfield, UT. The 509th was tasked with the deployment of the world’s first nuclear weapons, atomic bombs dropped on Hiroshima and Nagasaki, Japan in August 1945. While assigned to the 313th, it was operationally controlled by the Headquarters of the 20th Air Force.
The 509th was commanded by Lieutenant Colonel Paul W. Tibbets. Its Group Camp was located adjacent to North Field, securely isolated from the other military camps which were located several miles from the airfield near the center of the island. Due to its mission secrecy, the operation of the 509th was more self-contained than the other bomb groups and drew little in resources from the 313th Wing.

The 509th operated highly classified “Silverplate” B-29s, specially designed to carry nuclear weapons. While the tail marking of the 509th was officially a Circle Arrow, the Silverplates were given the tail markings of other Bomb Groups on the field to blend in and prevent Japanese spies on the island from identifying them as special. The Enola Gay carried the Circle R tail marking of the 6th Bomb Group for its atomic mission over Hiroshima. The 509th planes were always kept under tight security.

Atomic Bomb Pits

The Seabees built two atomic bomb loading pits on the northwest side of Runway A, one for each of the two dropped atomic bombs, Little Boy and Fat Man. The weapons were too large to be loaded conventionally into the bomb bays of the B-29. Each bomb was pre-loaded onto a hydraulic lift within its loading pit. The B-29 was backed over the pit with its bomb bay doors open so the bomb could be winched from the pit into the plane. The atomic bombs were assembled within a highly classified and secured building within the 509th camp and transferred under wraps on special trailers to the atomic bomb pits. Watch Atomic Missions video for rare footage of 509th operation and bomb loading

B-29 Service Facilities

B-29s having maintenance and service needs that could not be handled by individual ground crews or specialists at the hardstand were taken to a large service facility manned by USAAF Air Service Groups located on the northeast corner of North Field. The service complex extended to the northern tip of the island and included living quarters for the service personnel. The services included engineers and repair-specific service personnel, with dedicated shops for armament, communications, electrical, fabric, instruments, machining, parachute, propeller, sheet metal, vehicle, welding and woodworking. Flak and fighter-damage repair as well as engine repair and replacement were very common B-29 service needs. The 359th, 58th, 77th and 72nd Air Service Groups operated at North Field.

Runways and Overloaded B-29s

SOME B-29S ABORTED TOO LATE OR FAILED TO LIFT ON ROLL AND SLID DOWN THE ABRASIVE CORAL CLIFF, IGNITING THEIR FUEL TANKS AND OFTEN THEIR ORDINANCE.

The Seabees constructed North Field’s level runways by building up crushed coral at their ends where the island elevation naturally descended at the coastline. Each of the four 8500 foot (1.6 mile) runways consequently terminated at a 50 foot high coral cliff. This created significant risk for the typically fuel and ordinance overloaded B-29s that needed the full runway to exceed stall speed (roughly 140 mph) for takeoff. Some B-29s aborted too late or failed to lift on roll and slid down the abrasive coral cliff, igniting their fuel tanks and often their ordinance. A stake was positioned along each runway as a go-no-go point for pilots. If a B-29 was not already at 100 mph with all engines performing perfectly at the stake, the pilot still had enough runway remaining to safely stop his 65 ton plane. 6th Bomb Group A/C Ed Vincent was credited as being the first pilot to drive his accelerating B-29 off the end of the runway and over the cliff edge at full throttle to gain added speed at level flight or even dive a little over the cliff to gain enough flight speed in the air space beyond the end of the runway to safely roll to gain altitude. This was copied by many pilots. [See Ed Vincent B-29 Missions video for details]