A few days prior to the attack on Pearl Harbor, Maj. Gen. Lewis H. Brereton, commander of the U.S. air forces in the Philippines, was closely watching the deterioration of diplomatic relations between the U.S. and Japan. A 500 mile gap that stood between the 35 B-17s under his command at Clark Field and Japanese air forces at Formosa, which was well within flying range of Japanese fighters. Concerned, Brereton requested permission to move the B-17s 500 miles south to the airfield on Del Monte, which was still under construction. On December 4th, permission was granted to move eight planes each from the 14th and 93rd Bomb Squadrons of the 19th Bomb Group.
Four days later (since they were on the other side of the International Date Line), word of the Japanese raid on Pearl Harbor quickly spread around Clark Field and the men stationed there knew that it was only a matter of time before their base was attacked. Three times, Brereton requested permission to attack Formosa, which, owing to the chaos in Hawaii, was denied. Still, at 0830 15 B-17s took off to patrol the area. Brereton received a call from MacArthur himself a couple of hours later, granting him permission for the strike.
As crews prepared for the attack, a radar station on the west coast of Luzon at Iba Airfield picked up incoming Japanese aircraft before communications were cut off as the airfield was attacked. They would arrive over Clark Field within an hour. When the raid on Clark Field began, only the P-40s had been able to take off and they had been diverted from protecting Clark Field. Just like the scene at Pearl Harbor, B-17s were lined up on the runway, easy targets for the 53 “Betty” bombers above. The Japanese had expected a fierce fight from the Americans instead of a repeat of what happened hours earlier in Hawaii. Men could only watch helplessly from foxholes as their planes were bombed and strafed. In the end, most of the B-17s and about a third of the P-40s were destroyed.
In the days following the Clark Field attack, most of the 19th Bomb Group air and ground crews were moved to Del Monte. The few that stayed behind tried to repair some of the B-17s that had been damaged and to stage missions. Between combat and reconnaissance missions and being on the receiving end of several Japanese strikes, the number of operational B-17s dwindled. Allied forces had to withdraw to Java by the end of December 1941 and on February 26, 1942, all forces were ordered to withdraw from Java to Australia. By this point, the 19th Bomb Group’s replacement, the 43rd Bomb Group, was sailing toward Australia on the Queen Mary.