On 25 February the PAVN deluged FSB 31 with artillery fire and then launched a conventional armored/infantry assault. Smoke, dust and haze precluded observation by the FAC aircraft, which was flying above to avoid anti-aircraft fire. Tactical air strikes destroyed several armored vehicles attacking the southern perimeter, but at 15:20 20 tanks supported by infantry attacked the northwest and east. At that time a USAF F-4 Phantom jet was shot down in the area, the FAC left the area of the battle to direct a rescue effort for the downed aircraft crew, sealing the fate of the base. PAVN troops and tanks then overran the position, capturing the ARVN brigade commander in the process. FSB 31 was secured by the PAVN at an estimated cost of 250 killed, and 11 PT-76 and T-54 tanks destroyed. The Airborne had suffered 155 killed and over 100 captured. Ironically, the two Phantom pilots were not recovered by the search and rescue effort that had abandoned the firebase; instead, they wandered in the jungle for two more days before being picked up. At a meeting held at Đông Hà between Generals Sutherland and Đống, the Airborne commander railed against Lãm and the Americans for not supporting his forces adequately. He was supported in his allegations by Colonel Arthur Pence, the senior U.S. advisor to the Airborne Division. Sutherland, infuriated by Pence's open support of Đống, relieved him of his duties.