Back to Pearl Harbor, December 7th, 1941
This post describes the radar facilities on Oahu, specifically the Opana Radar Station, during the early hours of 7 December 1941. All times specified are local Hawaiian time.
The U.S. Army was responsible for defending all military installations in Hawaii against aerial attack. The Signal Corps had planned an aircraft warning service consisting of an Information Center at Fort Shafter and nine radar stations, three fixed and six mobile. By 7 December 1941, the six mobile stations were in operation but the towers for the three fixed station were on the dock at Oakland, California.
THE U.S. ARMY'S AIR WARNING SYSTEM (AWS)
The key to the Hawaiian Islands air defence was the air warning system (AWS), consisting of radar units, an air warning center at Fort Shafter, Oahu, located 4.9 miles (7.9 kilometres) east southeast of Ford Island in Pearl Harbor, and the 14th Pursuit Wing at Wheeler Field, Oahu, located 9.4 miles (15.1 kilometres) located north northwest of Ford Island in Pearl Harbor. As the heart of the AWS, the air warning center contained an information center, fighter director, and an aircraft/antiaircraft weapon control system. The information center needed to receive data about incoming aircraft, either from long-range reconnaissance, units stationed on the outer islands, surface ship contact, or radar in order to operate. Aircraft plotters marked the flight paths on a table map where the director, with liaison officers from the U.S. Army Air Force's 14th Pursuit Wing and 18th Bombardment Wing at Hickam Field, Oahu, located 2.0 miles (3.2 kilometres) south of Ford Island in Pearl Harbor, the U.S. Navy, and civilian aviation, identified them as either friendly or unknown. If marked unknown, the director ordered fighter interceptors launched, under the aircraft controller's direction, to investigate. This was how the British operated their aircraft warning system, and in theory this was what the U.S. Army's Hawaiian Department had in place at Fort Shafter. In actuality the system used in Hawaii bore little resemblance to the British system. The whole AWS idea was so new to the Army that no one was sure how to make it work or who should control it. The cooperation needed among various military units and government agencies was far greater than anything anybody realized at the time. Because the mobile radar systems were the first units developed for the AWS, the Army Signal Corps took initial control. The Signal Corps had planned to deploy nine radar stations, three fixed and six mobile. By 7 December 1941, the six mobile stations were in operation but the towers for the three fixed stations were on the dock at Oakland, California. After the Signal Corps had set up the system and trained the personnel, control would pass to the Hawaiian Air Force. Contrary to popular belief, the air warning system as used in Hawaii on 7 December 1941 was under the Army Signal Corps, not the Hawaiian Air Force.
Lieutenant Colonel Carroll A. Powell, Army Signal Corps, was in charge of the Hawaiian air warning system that morning. To help Powell in setting up the system and to take operational control upon its completion, Brigadier General Howard C. Davidson, Commanding General 14th Pursuit Wing, selected the 44th Pursuit Squadron (Interceptor) Commander, Captain Kenneth P . Bergquist. Although Bergquist was known as a troubleshooter and had a reputation for getting the job done, the task of making the air warning system work before 7 December would prove to be too much for even his abilities. Everyone wanted to get into the act. Even the simplest job took months of coordination and frustration before it could be completed. Oahu abounded with US Government-owned locations suitable for the mobile radar units; but before a site could be used, approval had to be obtained from the National Park Service and the Department of Interior. More than once, Lieutenant General Walter C. Short, Commanding General Hawaiian Department, U.S. Army, had to intervene to get the approval process moving. Cooperation within the Army was no better. Captain Bergquist placed a requisition for headsets to be used by personnel operating the control center, only to have it disapproved by the Quartermaster Corps because the latter thought the Signal Corps was the organization in charge and, therefore, authorized to request items.
After completing the air warning center construction at Fort Shafter, personnel needed to be trained to operate it. The Army's Signal Corps handled training for the personnel required to operate the radar units and those at the air warning center involved in tracking the reports on incoming aircraft. Captain Bergquist, with Captain Wilfred H. Tetley, U.S. Army Signal Corps, and Lieutenant Commander William Taylor, USN, managed training of directors, controllers, and those personnel who would be temporarily assigned to the system during exercises and wartime operations. Tetley and Taylor were detached from their respective units and in no way represented the Signal Corps or the Navy during this training phase. In other words, the Signal Corps trained part of the personnel and the Hawaiian Air Force the rest, with no one in command of the complete training. During the two main exercises held with the U.S. Navy in 1941 and during several smaller exercises conducted by the center itself, either the director knew the direction of the attacking aircraft or personnel from the other branches would report for the exercise as liaisons so the incoming aircraft could be identified. On 12 November 1941, after the center was manned, the Navy launched a simulated strike from an aircraft carrier 80 miles (128.7 kilometres) out to sea. The radar stations easily picked up the attackers, the center quickly identified them as enemy aircraft, and within six minutes interceptor aircraft were airborne and met the attacking force 30 miles (48.3 kilometres) from the island.
These exercises demonstrated that the Hawaiian air warning system would work if it had operational radar units, a fully staffed information center, and armed and ready-to-fly interceptor aircraft. During the simulated enemy attack on 12 November 1941, the AWS received information from (1) mobile radar units, (2) long-range reconnaissance aircraft, (3) ships at sea, and
(4) outer island units. The information was fed to the AWS and the director fed information to (1) U.S. Army Air Forces, U.S. Navy and Civilian aviation representatives; (2) an aircraft controller who was in contact with the 14th Pursuit Wing which controlled U.S. Marine Corps and U.S. Navy fighter units; and (3) to an antiaircraft artillery controller who relayed the information to antiaircraft artillery units.
The best General Davidson could do was to ensure at least one pilot from the 14th Pursuit Wing was on duty every day in the air warning center to learn firsthand how the whole system operated and to offer assistance to the controller in handling pursuit aircraft. To save money, manpower, and wear and tear, the six mobile radar stations only operated during the following hours:
Sunday: 0400-0700 Monday thru Friday: 0700-1100 and 1200-1600
Saturday: 0700-1100
An Information Center, located at Fort Shafter, consisted of a plotting board where plotters marked the position of aircraft picked up on radar or by coast watchers. The plotters had no way of distinguishing friend from foe. Two officers were also on duty, a controller and a pursuit officer. The pursuit officer was "to assist the Controller in ordering planes to intercept enemy planes or supposed enemy planes, after the planes got in the air."
The best of the mobile radar stations was the Opana Mobile Radar Station which was located 230 feet (70 meters) above sea level near Kahuku Point on the northern tip of Oahu. The site consisted of a few tents and two equipment trailers. The radar set itself had a range of approximately 130 miles (209 km).
At 0400 hours on Sunday, 7 December 1941, Privates Joseph L Lockard and George E Elliott went on duty. Lockard was the more experienced of the two and began instructing Elliott in the use of the equipment. At 0700 hours, Lockard began shutting the radar unit down but because the truck taking them to breakfast was late, Elliott convinced Lockard to leave the radar system on for additional training. At 0702 hours, they picked up more than 50 aircraft bearing 005 degrees at 132 miles (212 km). After checking the radar to ensure that it was functioning correctly, Private Elliott called the Information Center to report. The conversation lasted seven or eight minutes during which time the target moved 20-25 miles (32-40 km) closer to Oahu.
Since the Information Center was located on an Army post, the plotters and Controller did not have to wait for a vehicle to take them to breakfast. Therefore, the center was closed promptly at 0700 hours and by the time Elliott called, there were only two people left, the switchboard operator and the Pursuit Officer. Strangely, the tour of duty for the Pursuit Officer lasted until 0800 hours. The Pursuit Officer that morning was Lieutenant Kermit A Tyler, a fighter pilot in the 78th Pursuit Squadron (Interceptor) at Wheeler Field. Tyler's first experience with the Information Center was on 3 December, four days earlier. It never occurred to him that this incoming flight could be enemy aircraft. He almost immediately remembered that a flight of 12 Boeing B-17 Flying Fortress' were enroute from California and due to arrive about an hour later. When plotted at the Opana Radar Site, the B-17s would bear 010 degrees, 5 degrees east of the bearing of the Japanese aircraft. Tyler told Elliott that his target was the B-17 flight at approximately 0720 hours when the target was at 74 miles (119 km), bearing 003 degrees. Lockard and Elliott continued to track the target until 0739 hours when ground clutter interfered. At that time, the target was at 20 miles (32 km) bearing 041 degrees.
Lockard and Elliott made one big mistake. They neglected to tell Lieutenant Tyler that the sighting consisted of more than 50 aircraft. If they had, perhaps Tyler would not have confused the blips with a flight of 12 B-17s. Then again, this is one of the great "What If" discussions of the war.
The Opana Radar Station continued operating during the morning and tracked the Japanese aircraft when they headed north back to their carriers. The Information Center at Fort Shafter recorded these reports at 1027 and 1029 hours. However, the high command had convinced themselves that the Japanese carriers lay in a southerly direction and the radar reports were ignored. This is another "What If" discussion.
Jack McKillop