"OPERATIONS OF 503D PRCT IN THE CAPTURE OF CORREGIDOR"
16 February 45 was the beginning of one or the most unusual airborne operations in the Southwest Pacific Area during World War II. This operation was unusual in that it departed from most all the established principles concerning airborne operations.
This is an account of the Airborne Assault on Corregidor Island, Philippine Islands during the period 16 February - 2 March 45. Some people have referred to this operation as "Operation Coordination" due to the fact that the coordination and cooperation between the services made it a practically perfect operation.
The author emphasizes the planning relative to this operation because it is felt that planning is more important in an airborne operation than in a normal ground assault.
It is the intent of this monograph to show how a well trained airborne unit vertically envelopes and defeats a strongly entrenched and numerically superior enemy on a small rugged island. This monograph will also show how some principles of war may be disregarded if other principles are properly emphasized.
The opening of the Luzon Campaign in the Northern Philippines was the beginning of the end for the Japanese Forces in this string of islands. The expulsion of the Japanese from these islands began with the amphibious landing on Leyte Island, 21 October 44 (See Map A). This campaign was followed by the amphibious invasion of Mindoro by two regimental combat teams, the 19th Infantry and 503d Parachute Infantry. There was very little opposition to the latter operation and the island was quickly secured. Mindoro was still nearer the Japanese stronghold of Luzon and furnished an excellent base for air operations against the major portion of Japanese Forces in the Philippines. Luzon was the third step in the recapture of the islands and is considered the most important because it was on this island that the enemy had massed his forces. The United States Sixth Army under command of General Walter Krueger was assigned the mission of recapturing Luzon and surrounding smaller islands and to open Manila Harbor; the largest harbor in the Philippines. (1) (See Map B)
In brief, the mission assigned Sixth Army was as follows: "To land in the Lingayen-Damartis-San Fernando (La Union) areas of Luzon; (2) to establish a base of operations, including facilities for uninterrupted naval and air operations; (3) to advance southward and seize the central Plain-Manila area; and (4) by subsequent operations, as directed by General Headquarters Southwest Pacific Areal to establish control over remainder of Luzon". (2)
The execution of this mission began with the landing in Lingayen Gulf area by XIV and I Corps on 9 January. These landings were followed by an advance inland and to the south towards Manila. (3)
Meanwhile activity was also taking place south of Manila. Landings were made by elements of the United States Eighth Army in the vicinity of Nagsugbu Bay in the Batangas area and the push towards Manila was on. Among the Eighth Army troops, participating in this landing was the llth Airborne Division. As demonstrated by this and the landing on Mindoro, the airborne forces were ready for operations other than airborne. (4) (Map B)
One objective of these two landings, in addition to gaining control of and clearing Luzon, was the capture of the city of Manila. The Philippine Islands, as a whole, would provide bases for future operations against the Japanese homeland. With the fall of the islands, the Japanese holdings in the Pacific would be threatened because it would be much easier for United States Forces to cut their supply lines. (5) As you can see from the map, a pincers movement was on to separate the Japanese Forces on Luzon and take the city of Manila and pave the sway for establishment or the needed bases.
On 3 February 45, the advance elements or 1st Cavalry Division, which was spearheading the United States Sixth Army drive, reached the outskirts of Manila. Earlier in the planning phase, it was believed the Japanese would not defend the city but as U.S. forces approached the city, it was determined they would defend to the end. (6)
Manila, without the use of the harbor facilities, would be of little use to the United States Forces. To gain access to the bay, it was necessary to gain control of Corregidor. This island's location was excellent for defense of the bay and city. It was located in the entrance to the bay with a channel on the north side and one on the south (Map B). Any craft attempting to enter the harbor must pass under the mouth of its guns. The coastal defenses, prepared by the Americans, had been destroyed by the Japanese siege in May 1942, and others were destroyed during our bombardment in 1944 and early 1945. Some of these guns had been returned to operational status by the Japanese prior to our invasion of the islands in 1945, but the preliminary bombardment prior to the assault had rendered most of them useless. (7)
Manila Bay, and the channels thereto, were heavily mined and the Japanese were securely entrenched along the coast believing themselves capable of repulsing any amphibious attack against the island fortress. (See Map C). It was learned from prisoners of war and documents captured on the island that the mines were controlled by a switchboard and it was possible to detonate them one at a time or all at once. (This switchboard was captured intact by the assault forces in the invasion of the island) With the coastal defenses facing onto the bay, minesweeping was made difficult. Too, there were many "Q" boats operating from the island. These boats were more or less one and two man torpedoes. They were small inboard motor boats carrying an average of 400 lbs of explosives in the nose. One method of employing these craft was to slip out quietly and crash into the side of a ship with much the same effect as a conventional torpedo. Since most of the fortifications to repel an amphibious assault were reinforced concrete constructed by U. S. Engineers, it was practically impossible to bomb the defenders out. During a bombing attack they would go below ground into the many caves and tunnels and wait it out. These factors made it impractical to minesweep the channels. (8)
The inadvisability of • an amphibious assault on the island was demonstrated by the heavy losses suffered by the Japanese at the hands of a small number of half starved United States and Filipino defenders in May 1942. (9)
The overall plan for the capture of Corregidor was as follows: The United States XI Corps was given the mission of opening Manila Bay by Sixth Army Order No. 48 issued 7 February 45 which read in part as follows: "XI Corps - On D plus 1 employing the 503d Parachute Infantry Regiment in airborne operations as arranged with Eighth Army and by shore-to-shore operations from Mariveles Bay area will capture Corregidor. Control of 503d Parachute Infantry passes to XI Corps upon completion of the drop on Corregidor." (See Map B) (10)
Although XI Corps was assigned the operational phase of the assault on Corregidor, the airborne phase was mounted by the United States Eighth Army from the island of Mindoro P. I. (11)
The 503d Parachute Regimental Combat Team, composed of 503d Parachute Infantry Regiment, 462d. Parachute Field Artillery Battalion and 161st Airborne Engineer Company was in training on the island of Mindoro, P. I. As stated previously, this organization participated in the initial assault on this island. The operation having been completed, the regiment was in the process of reequipping and undergoing some training. On 3 February 45, the Regimental Commander was alerted for a parachute drop to capture Nichols Field in the vicinity or Manila. Due to the rapid advance of the ground forces on Luzon, this mission was cancelled on 5 February and the Combat Team alerted for the drop on Corregidor to take place on 12 February 45. Although the 503d was not alerted until 5 February 45, the reader should realize that preliminary bombardment had already begun, as early as 23 January 45. The extent of the bombing of this small island is indicated by the fact that in less than a month 3,128 tons were dropped. (12)
When the Combat Team Commander, Colonel George M. Jones, received the change in missions on 5 February, he set about changing plans for the new objective. There was little, if any, change as far as the troops were concerned. The preliminaries are the same for any airborne operation regardless of the objective. They consist mainly of checking and replenishing equipment and general readiness for combat. (13)
ORDER OF BATTLE
There were troops other than the 503d Regimental Combat Team participating in this operation. So that the reader will understand the size and support received during the operation, the following troop list is quoted:
" 1. 503d Regimental Combat Team
a. 503d Parachute Infantry Regiment
b. 462d Parachute Field Artillery Battalion
c. 161st Airborne Engineer Company
2. 3d Bn 34th Infantry Regiment reinforced by
a. 3d Platoon, AT Co, 34th Inrantry
b. 3d Platoon, Cannon Company, 34th Infantry
3. 18th Portable Surgical Hospital (Reinforced)
4. 174th Ord Ser Det (Bomb Disposal)
5. Det 592d EBSR
6. Det 98th Sig Bn
7. Det 1st Plat, 603d Tk Co
8. Det 592d JASOO*
9. Dot 6th SAP**
10. Det Naval Task Force
11. Elements of Fifth Airforce including 317th TC Group" (14)
When the Combat Team Commander informed the staff that the new, objective was Corregidor, they were somewhat amazed when they considered the size of the island and recalled the "requirements" ror desirable drop zones. (15) Upon first glance it appeared there was no place to drop the troops.(Map C) Arrangements were made with the army air force for the regimental and battalion commanders and selected staff officers to fly over the island in planes making air strikes against Bataan. When this aerial reconnaissance was accomplished, the ROT Commander called the battalion commanders together and, with a study of aerial photographs, it was determined there were three possible areas where a drop might be made. These were: (1) the remains of a small golf course, (2) an open area that had been used for a parade ground in days of peace and (3) Kindley Field, a small air strip on the tail of the island. These could hardly be classified as desirable drop zones but there were none better. Kindley Field was ruled out almost immediately, because of its location. As stated previously, it was on the "tail" of the island and even if a -successful drop was made at that point', it would be necessary to overcome defenses prepared for an amphibious assault before the high ground could be taken and the island secured. The other two had few of the desirable characteristics for drop zones. The parade ground, though level, measured only 150 by 200 yards and was surrounded on three sides by concrete barracks and other buildings. The golf course was approximately 150 by 275 yards and sloped steeply down to an abrupt drop to sea level. Combined, they were much smaller than anything used for a parachute drop in the Pacific Theater. The RCT Commander had confidence in the capabilities of his troops and a thorough knowledge of airborne technique. He felt the mission could be accomplished successfully although he expected the drop casualties to run high, possible 20%. (16)
To ensure that the reader realizes some of the problems facing the commander in the detailed planning of this operation, it is well that we include a description of the topography of this island. (See Map C) The island is approximately one square mile in area and is divided into three sectors, (1) "Topside" "Bottomside" and "Middleside". "Topside", on the western end of the island, is the highest part and it was on this part that Fields "A" and "B" were located. "Bottomside" is that part of the island lying east of Malinta Hill and is called the "tail" of the island. "Middleside" is the area between the other two. Malinta Hill rises to a height of only 350 feet but is the dominating terrain feature on Middleside. Monkey Hill, very small, is the dominating terrain on Bottomside. Corregidor is bounded in many places by sheer cliffs approximately 500 feet high dropping off to the waters edge. The only open and flat terrain on the island is on "Topside", and comprises the area of the old parade ground and golf course which were designated Fields "A" and "B" respectively. The entire island is guttered with deep ravines with precipitous sides. The aerial bombardment had stripped the trees of any foliage and splintered and shattered the trunks until they created a parachute hazard, The bombing had also wrecked the buildings. The barracks buildings were of the three story reinforced concrete type and, after bombing, created still another parachute hazard. The fields selected for the drop abounded in bomb craters, huge boulders and large sunbaked clods of clay which were almost like rock themselves. The cliffs facing the beach, sides of the ravines and the old gun batteries had been made into well fortified positions. The latter was not determined however, until after landing on the island. This is exemplified in the intelligence estimate of the terrain. An excerpt from this estimate is as follows: "A close comparison of the installations of the is-land in recent extensive photography of CORREGIDOR with its pre-war appearance clearly shows that little attempt has been made during the Japanese occupation to develop it." (17) The Japanese had indeed been clever in concealing the development of their defensive organization. Several all weather roads covered the island but these too had been damaged to some extent by our bombers. The terrain definitely favored the enemy for a good defensive stand. This was the terrain setup into which the RCT was going. In addition, intelligence estimates placed the strength of the Japanese garrison at 850. (18)