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THE SECOND AERIAL BOMBARDMENT
Early in January, it will be recalled, Imperial General Headquarters had transferred the bulk of the 5th Air Group out of the Philippines, leaving General Homma with only a small air force whose major mission was to support ground operations on Bataan. A month later, after 14th Army had been badly beaten in its efforts to gain a quick victory on the Orion-Bagac line, Homma had received large reinforcements, including Army and Navy air units. From Malaya had come two heavy bombardment regiments, the 60th and 62d, with a total of sixty twin-engine bombers. This single accretion alone tripled Homma's air strength. In addition, the Navy had sent two squadrons of Bettys (land-based, twin-engine bombers), one squadron of Zekes (fighters), and one squadron of carrier-based bombers to the Philippines, thus making available for the offensive of late March and early April a considerably augmented air force.
Homma's plan for the final assault against the defenders of Bataan had provided for a heavy artillery and aerial preparation, starting on 24 March and continuing until victory was achieved. To the air forces he had assigned a threefold mission: to support he advance of ground units, bomb forward and rear installations, and cut he line of supply between Bataan and Corregidor. All aircraft were given targets on Bataan; but the 60th and 62d Heavy Bombardment Regiments and the Navy were directed to bomb Corregidor as well. Careful plans were made for the period from 24 to 28 March and an agreement was concluded between the Army and Navy which made possible a unified plan of air action and the joint bombardment of targets by the aircraft of both services. After the 28th the bulk of the heavy bombers were to concentrate on Bataan, but, "in order to demoralize the enemy and to boost the fighting spirit of our army," a small number of planes would continue to bomb Corregidor every few hours around the clock.
The aerial attack opened on schedule simultaneously with the artillery preparation on Bataan, at dawn of the 24th, when the first of the Army's six bomber squadrons rose from Clark Field and headed toward Corregidor. At the same time two navy squadrons (twenty-four Bettys) stood by to take off from their base at Clark near Manila to join in the attack. At 0924 the air-raid alarm, the seventy-seventh of the campaign, sounded on Corregidor. One minute later, the first enemy flight of nine Army bombers came over the island to drop their 550- and 1,100-bombs. They were followed by the remaining Army squadrons which, in turn, gave way to he Navy's planes. The attack continued during the day and that night, when three more planes made a nuisance raid against the island. Altogether, forty-five of the sixty twin-engine bombers of the 60th and 62d Heavy Bombardment Regiments and the two squadrons of naval land-based bombers participated in the first day's attack to drop a total of seventy-one tons of bombs.
The next day the Japanese sent only three Army squadrons, twenty-seven planes, against Corregidor; the Navy, a similar number. This pattern continued until the 29th, the Navy planes alternating with the Army bombers. In addition small groups of planes came in over Corregidor every two or three hours "to carry out the psychological warfare and destroy the strong points, without failure." The routine bombings continued steadily until 1 April, with at least one Army squadron attacking during the day and another at night. The Navy planes, which had no missions on Bataan, continued their bombardment of the island fortress in undiminished strength.
For the men on Corregidor it seemed as though they were living "in the center of a bull's-eye." During the last week of March there were about sixty air-raid alarms lasting for a total of seventy-four hours. Bombings begun in the morning were usually resumed in the afternoon and again at night. Since the Japanese planes were now based on Clark Field or near Manila, they were able to remain over the target for longer periods than they had during their first bombardment in December. A graphic picture of the intensity of the bombardment can be gained from General Moore's summary of the first day's action.
Batteries Woodruff [Ft. Hughes, 14-inch guns], Marshall [Ft. Drum, 14-inch guns], and Koehler [Ft. Frank, 12-inch mortars] opened fire on Cavite targets.
Air Raid Alarm No. 77 sounded.
Nine heavy bombers, a new type in the area, bombed Middleside and Morrison Hill.
Twenty-seven heavy bombers came in over tail of Corregidor and bombed Middleside, closely followed by 17 heavies bombing Topside.
Twenty-five planes followed by 9 more made another attack. Meanwhile, artillery shells from enemy batteries in Cavite were bursting on Corregidor. Several fires were started, communication cable and water mains cut, and an ammunition dump of 75-mm. shells on Morrison Hill was set off. These shells were exploding for hours. Battery Wheeler [12-inch guns] had a direct bomb hit on the racer of No. 1 gun putting it out of action temporarily.
All clear sounded.
Air Raid Alarm No. 78. Nine heavy bombers approached Corregidor from the southeast. Bombs dropped on Kindley Field.
Seven more planes from southeast with more bombs. Shelling from mainland also.
Air Raid Alarm No. 79. Nine heavy bombers hit Kindley Field again.
Air Raid Alarm No. 80. Mariveles and Cabcaben areas [Bataan] hit by 9 heavies.
Air Raid Alarm No. 81.
First night air raid. Two medium bombers dropped incendiary bombs in Cheney Ravine, Corregidor. Later returned and bombed Bottomside. No damage reported.
The effect of so heavy a bombardment over the period of seven days might well have been disastrous had not the men profited from the earlier air attacks and built underground shelters. They had also learned how effectively sand could cushion the blow from a bomb and had made liberal use of sandbags. "It used to be hard to get the men to fill sandbags," wrote one officer. "Now it is hard to keep them from laying hands on all the sandbags available and filling them when those to whom they are allotted aren't looking." The small number of casualties is ample evidence of the thoroughness with which the Corregidor garrison had dug in since the first attack on 29 December.
Installations of all kinds and critical supplies had also been placed under bomb-proof protection, and these suffered little damage during the bombardment. The few remaining surface installations, however, and supplies in open storage did not fare so well. On Bottomside, the theater, post exchange, and bakery were leveled to the ground and the Navy's radio station damaged. Wainwright's house, inherited from MacArthur, was destroyed on the first day of the attack. "I picked up the light walking stick which MacArthur had left for me," wrote Wainwright, "and walked down to Malinta Tunnel to live there the rest of my time on Corregidor." Several ammunition dumps were hit, exploding the shells in storage, and a quantity of TNT blown up. But losses, on the whole, were small and were quickly repaired by crews which cleared the roads and cleaned out the debris left by exploding bombs.
The Japanese, too, seemed to have profited by their earlier experience and had "learned," Captain Ames observed, "to dodge AA fire." They came in at higher altitudes than before, between 22,000 and 28,00 feet, in formations of nine planes or less. During daylight they made their bombing runs out of the sun, changing course and altitude immediately after the moment of release. Earlier the antiaircraft gun batteries had been able to get in about ten salvos before the Japanese flew out of range, usually bringing down the lead plane of the formation. When the enemy changed his tactics, the antiaircraft guns could get in fewer salvos and could no longer count on the lead plane maintaining the same course.
Under ideal conditions antiaircraft guns form a ring around the defended area, or a line in front of it, from where they can strike enemy aircraft before they reach the objective. On Corregidor it was not possible, for obvious reasons, "to follow the book." The antiaircraft guns could not engage the enemy until he was almost over the island. Moreover, by being located on the target, they became "part of what is being bombed," with the result that their efficiency and freedom of fire was limited most at the moment of greatest need. "Naturally our job is to fire on the bombers," wrote Captain Ames, ". . . and if possible prevent the bombing. Fire we do, but prevent the bombing we cannot." In a letter which never reached his wife he graphically explained the difficulty which beset all the antiaircraft men.
The bombers come over; we see them drop their bombs--all the while we are tracking them with our instruments--our guns point upward more and more steeply; the bombs continue downward on their way towards us. Then our indicators show that the bombers are "in range". We open fire. in about 15 seconds our guns are pointing as nearly straight up as they can, and hit the mechanical stop. We cease firing. The bombs whistle; we duck for a few seconds while the bombs burst, and pop up again to engage the next flight. When fighters come in one after another we stay up while the bombs hit all around us. . . .
Some of the bombers come in higher than we can shoot. In such cases we vainly wait for our indicators to show "in range", and take cover (duck behind our splinterproofs) just as the bombs begin to whistle.
The most serious limitations on the effectiveness of the 3-inch guns arose from the shortage of mechanically fuzed ammunition, which could reach to a height of 30,000 feet. There was an adequate supply of ammunition with the powder train furze, effective to a height of about 24,000 feet, but only enough of the longer range type for one of the ten antiaircraft batteries. On 3 February a submarine had brought in 2,750 more rounds of mechanically fuzed ammunition, and it became possible to supply an additional battery. Thus, when the enemy planes came in at an altitude of more than 24,000 feet, only two batteries could reach them. The remaining batteries of the antiaircraft command, equipped with powder train fuzes, could only watch idly while the Japanese leisurely dropped their bombs. Nonetheless, the contribution of these batteries, though negative, was a valuable one. By forcing the enemy to remain at extremely high altitude, they decreased his accuracy and diminished the effectiveness of the bombardment.
From the outset it had been necessary to conserve even the powder train fuzed shells, 30 percent of which were duds. This had been accomplished by limited each gun to six rounds for any single target on any given course. The opening weeks of the war proved the most expensive in terms of rounds fired to planes destroyed, 500 rounds being required for each plane. This inaccurate fire was due to inexperience, the irregular functioning of powder train fuzes, and variation in the muzzle velocity. Between 8 December and 11 March the 3-inch gun batteries in the harbor defenses expended over 6,000 rounds for a total of 52 aircraft knocked down, or about 120 rounds per plane. With increased experience of both fire control crews and gunners and improved fire discipline, this average was steadily bettered until, by the beginning of April, the expenditure rate went under 100 rounds per plane, an excellent score even under the most favorable conditions.
In February an effort was made to use the 12-inch mortars for antiaircraft fire in the hope that a salvo from these pieces, bursting in the midst of the enemy formation, would discourage mass bombing. The 670-pound shells were first fitted with the powder train fuze but the shell would not explode. Next, the 150-mm.. shrapnel and the mechanical antiaircraft fuze were tried, but they failed also to detonate the charge. "If it can be made to work," thought Colonel Bunker, "it will sure jolt the Japs." But the problem was never solved, and at the end of the campaign Ordnance still did not know whether the 12-inch shell would not explode because of the low rotational velocity or the size of booster charge in the fuze.
With the second aerial bombardment of Corregidor the Japanese for the first time resorted to night bombing. During this period they made twenty-three such attacks, delivered by small groups of bombers from an altitude of 24,000 to 27,00 feet. In almost every case the searchlight batteries illuminated the planes before they reached the bomb release line. Many of the pilots seemed to be confused by the lights and turned away to approach from another direction; others jettisoned their bombs or abandoned the attack altogether. Those that got through were apparently too nervous and too anxious to get back to bomb with any accuracy. On the whole, the night attacks proved ineffective and after 6 April were discontinued.
By the beginning of April, the aerial bombardment was virtually over. little additional damage had been received and comparatively few casualties had been suffered by the men who had had two months to prepare. All eyes were now turned to Bataan, upon which the Japanese had concentrated their entire air and artillery strength in preparation for the final assault. For the next ten days, while the fight for Bataan ran its grim course to a bloody and tragic end, the men on Corregidor and its sister fortresses were granted a brief respite. Their turn, they knew, would come soon.
 This account of Japanese air plans and operations is based upon 5th Air Gp Opns, pp. 59-76; 14th Army Opns, I, 129-36; Comments of Former Japanese Officers Regarding the Fall of the Philippines, p. 74, OCMH.
 5th AIr Gp Opns, p. 60.
 Ibid., p. 65.
 Tisdelle, Diary, entry of 3 Jan 42.
 Harbor Defenses Rpt of Opns, pp. 46-47.
 Ames, Diary, entry of 26 Mar 42, and ltr to his wife, 8 Jan 42.
 Wainwright, General Wainwright's Story, p. 74.
 Ames, Diary, entry of 24 Mar 42.
 Ltr, Ames to his wife, 20 Jan 42, Ames, Diary.
 Bunker, Diary, entry of 20 Mar 42. This scheme and the efforts to put it into effect were neither supported nor indorsed by Colonel Chase, the antiaircraft commander, who regarded the entire project as "to say the least, fantastic." Chase, Comments on Draft MS, pp. 23-24, OCMH.