The Callender Report

Of primary importance in testing for the acceptability of any parachute operation is study of the available drop-zones and their immediate surroundings. The many. who have visited CORREGIDOR since its recent fa11 have invariably asked, "Where did they land?" There were three possible drop-zones. Of the three, one was an unused emergency landing field just north of MONKEY POINT, immediately discarded inasmuch as a descent here achieved nothing more than could be achieved by amphibious assault. The other two were on TOPSIDE and were respectively; "A", the Parade Ground, and "B", the golf Course of pre-war days, now overgrown and torn. No muttered curse, provoked by a sagging rank at review, or slice from No. 1 tee, could in any way express the feelings inspired in the minds and hearts of those who studied the air photographs of THE ROCK. The usable area of "A" field did not exceed 250 by 150 yards. �B� field was approximately 75 yards longer but no greater in width and the two combined provided the smallest area into which an air-drop of combat troops in any number, has as yet been made. Further, the very nature of these fields, surrounded as they were by splintered trees, tangled undergrowth and wrecked buildings, pock-marked with bomb and shell craters, and littered with clods, rocks, scrap iron, tin roofing, and other forms of debris, made them present an aspect that resembled Dante�s inferno. In addition, the fields sloped sharply at their extremities to drop off in sheer cliffs. Knowing the prevailing wind direction and the usual high wind velocity of from 15 to 25 miles, it could immediately be established by the officers formulating the plan that drop casualties alone might run as high as 20 percent. (See Overlay 1).

The assumption that the enemy strength on CORREGIDOR might not exceed 850, all ranks, and that the surprise would be complete made this figure appear as reasonable for the bulk of our expected casualties, while those to be expected from amphibious assault and subsequent up-hill attack might easily run much higher It was correctly assumed that the Jap was adequately prepared for the latter assault but, in all probability, would be caught flat-footed by the former. All other factors considered, the parachute descent was acceptable and the decision was made.

5. Information of the Enemy: FO No. 9 attached (Volume 2 of two) gives the minimum enemy strength on CORREGIDOR as 850. However, no information was available nor had any positive indication been received as to his scheme of defense. The locations of his major combat elements, command posts, and supporting weapons were matters for conjecture. What actually turned out to be the case might well have made a desperate venture of what was already a hazardous one, had the enemy given the slightest consideration to the possibility of parachute descent. His total strength on CORREGIDOR approached 6000. Of this number, 3000 were disposed on the defense perimeter of THE ROCK in prepared positions intended to meet amphibious assault. These positions, located in the deeply serrated ravines leading from the shore to TOPSIDE were like the fingers of a hand in that lateral movement along the beach or over the intervening ridges was extremely difficult and, secondly, lacked any lateral wire communication. Such wire communication as did exist was from the various strong-points to a central located on TOPSIDE, destroyed by early capture. The balance of the enemy force of approximately 3000 men was concentrated in the MALINTA HILL and TUNNEL area.

His plan of defense thus emerges: In general,

a. To prevent amphibious landings on the main portion of the island, i.e., THE ROCK.

b. To prevent amphibious landings at or near SAN JOSE.

a. To provide a reserve to reinforce the defense of THE ROCK.

b. To contain a landing on the tail south of SAN JOSE. Here again we see the pattern of Japanese military thought. It is a pattern that closely resembles that of the older military hierarchies of Europe,in that it considers only the conservative and eliminates from any consideration the unusual, or, what is more important, that which he would not do himself.

The enemy was provided with adequate stocks of weapons, ammunition, rations, water, and explosives, located in dumps conveniently situated with respect to his defensive installations. A major supply problem was water and no evidence exists that any provision was made for water supply after the existing stocks became exhausted.

6: Our Own Forces: Allocated initially to the Commanding Officer 503d RCT (Prcht) for the execution of the mission was:

a. (1) 503d RCT 2962

503d Infantry (Parachute)

462d FA Battalion (Parachute )

161st Engineer Company (Parachute)

(2) 3d Battalion, 34th Infantry. (Reinforced) 1598

TOTAL ROCK FORCE 4560

b. Supporting forces, consisting of Naval vessels, Air units, LCM units, etc.

7. The Plan:

a. Preparation: Preliminary to assault THE ROCK was subjected to bombardment for several days. Ships, gunfire and air bombing were employed. The purpose of these fires was to inflict casualties, destroy stores and installations, and disrupt communications in general but, more particularly, to reduce to a minimum the enemy strength kept on TOPSIDE during daylight hours. That it succeeded in the latter was found to be the case. The preparation was carried on to the time of the drop (See Overlay 2).

b. Aerial reconnaissance and photography was carried on but in such a mariner as to not draw too much attention and to conceal the intent of a parachute drop. Commanders to include company were flown over THE ROOK in bombers beginning 12 February. The aerial photography included verticals and obliques. A scale model of the island was made and studied by all personnel. Personnel who had served on the island during its defense in 1941-42 were interrogated, and maps and drawings available in the Theater were examined.

c. The Air Movement: Factors controlling an air movement are planes available, distance to the drop zones, and force to be transported. For this operation a total of about 56 C-47�s was made available. Flight time was estimated at 1 hour and 15 minutes. The force to be transported being roughly 3000 men, a plan employing three lifts was adopted. The first two lifts were to go in beginning at 0830 on 16 February, the last lift on 17 February.

Lifts to be made from SAN JOSE, MINDORO, were as follows:

(1) First lift, 51 C-47's take off 0715 16 Feb, over target 0830.

3d Bn 503d

Det Hq 503d

161st Eng Co

Det Hq Btry 462d FA Bn

Btry A 462d FA Bn (75mm How)

Plat Btry D 462d FA Bn (.50 cal HMG) '

(2) Second lift, 51 C-47's, take off 1100 16 Feb, over target 1215.

Det Hq 503d

2d Bn 503d

Sv Co 503d

Plat Btry D 462d FA Bn (.50 cal HMG)

Btry B 462d, FA Bn (75mm How)

(3) Third lift,43 C-47's, take off 0715 17 Feb, over target 0830.

Remainder Hq 503d

1st Bn 503d

Plat Btry D 462d FA Bn (.50 cal HG)

Btry C 462d FA Bn (75mm How)

(4) Fourth lift, (Resupply) 12 C-47's, to begin on completion third lift.

Twelve C-47's were allocated for daily resupply, to be replaced by amphibious resupply to SAN JOSE beach as the situation clarified and access to TOPSIDE by road was established.

d. Flight Plan: In the formulation of the flight plan consideration was, as usual, given to wind direction and velocity, and size of drop zone. A little more rigorous set of conditions than those actually encountered might readily have resulted in disaster. Prevailing winds at this season of the year are generally east winds with velocities of from 15 to 25 miles per hour with occasional gusts on TOPSIDE. Fortunately, the Prevailing wind direction coincided approximately with the long axis of the drop zones. However, it was recognized that the selection of the "Go" point had to be precise and that a stick taken out too soon or too late by even a second or two would put men over the cliffs. It is easily determined arithmetically that a C-47 travelling at dropping speed will move at a rate of about 150 f/s. The maximum feasible length of "A" field being 1050 feet and that of "B" field 975, the actual time over the drop zones would not exceed about 6 seconds. Stick time out of the plane is about .5 seconds per man. Using a drop altitude of 400 feet, time to the ground amounts to approximately 25 seconds. A wind velocity of 15-25 mph or 22-37 f/s would occasion a drift of from 500 to 900 feet during the descent, distances roughly equivalent to the length of the drop zones. If one adds the imponderables of gusts, fish-tailing, sharp diminution of wind velocity, and the nature of the terrain to the human errors, the margin of safety was nil and the hazardous nature of the drop is fully apparent.

Based on conditions to be encountered, it was decided to adopt a flight pattern of two columns of single planes in trail, one column over each field. Each plane to make a minimum of two or three passes as necessary, dropping a stick of 6 to 8 men on each pass. The initial sticks ore dropped from about 550 feet but this was soon reduced to 400 feet or less to reduce drift. (See Overlay 3)