During the first phase of Operation KILLER most of the sorties by 1st MAW planes were in support of U.S. Army units. On 23 February the Marines flew 101 of the Fifth Air Force total of some 800 sorties for the day.[108] The experience of VMF-312 was fairly typical of the other Marine fighter-bomber squadrons. In the morning VMF-312 took part in a 16-plane strike behind the CCF lines. That afternoon two special flights of four planes each were scrambled in support of 2d and 7th Infantry Division units of X Corps. The following morning Major Daniel H. Davis, executive officer of the squadron, scrambled with four planes and reported to a FAC attached to the Canadian and Australian battalions of the British Commonwealth Division. These troops were engaged near Chipyong-ni in the hottest fight of the first phase of Operation KILLER. After the FAC marked the CCF strongholds with white phosphorus, the Corsairs came snarling in with napalm, rocket, and strafing runs just ahead of the infantry. The enemy was driven out of positions defended by 20mm antipersonnel fire, but Major Davis paid with his life on his eighth run when he lost a wing and crashed to his death. [108] EUSAK _Cmd Rpt_, Sec III, Bk 4, Pt 5, 23 and 24 Feb; 1st MAW _HD_, 22–24 Feb 51. _General Smith in Command of IX Corps_ On 24 February 1951 came the news that General Moore had suddenly died as the indirect result of a helicopter accident. The aircraft had plunged into the Han River, after hitting a telephone wire, and the IX Corps commander was rescued unhurt only to die of a heart attack half an hour afterwards. Commander of the 8th Infantry Division in European operations of World War II, General Moore later became Superintendent of the U.S. Military Academy at West Point. As his successor, pending a permanent appointment, General Ridgway named General Smith to the command of IX Corps. When announcing this decision, the Eighth Army commander said, “General Smith is to be taken into their hearts in IX Corps, and, by definite action, made to feel that he belongs there.”[109] [109] EUSAK _Cmd Rpt_, Feb 51, Sec 2, 23. Marines with an interest in Corps history could recall only two similar occasions when Marines commanded major U.S. Army units. Major General John A. Lejeune had headed the 2d Infantry Division in World War I, and Major General Roy S. Geiger led the U.S. Tenth Army to victory during the closing days of the Okinawa operation after a Japanese shell killed Lieutenant General Simon Bolivar Buckner, Jr., USA.