The following missions were plagued with difficulties, but, after additional training, the team's performance improved dramatically. On 2 June 1967 SOG launched an operation against Oscar Eight, a PAVN base area located approximately south-southwest of Khe Sanh Combat Base (), believed to contain a PAVN field army headquarters. The target area was hit by nine B-52s which caused numerous secondary explosions, but an aerial observer could see PAVN troops in the area immediately afterwards. A Hatchet Force was then landed by nine H-34 Kingbees and five United States Marine Corps (USMC) CH-46s from HMM-165. The Hatchet Force was soon pinned down in the bomb craters and close air support aircraft were called in. One A-1 Skyraider was hit by flak and collided with another A-1 losing its tail and crashing into the ground killing its pilot, Lieutenant Colonel Lewis M. Robinson. The fighting continued throughout the night and the next morning it was decided to pull the force out. During the extraction two USMC UH-1E helicopter gunships from VMO-3 were shot down as was a Kingbee. A CH-46 succeeded in extracting part of the force, then a USAF F-4 Phantom was shot down. Another CH-46 came and extracted more of the force, but it was hit by antiaircraft fire and crashed from a height of . The PAVN fired on the survivors in the wreckage killing many of them. One of the survivors, Sergeant first class Charles Wilklow was dragged into a clearing covered by PAVN machine guns to be used as bait to attract a U.S. rescue mission. After four days Wilklow escaped into the jungle, was seen by a reconnaissance plane and then rescued by a Kingbee. The raid had cost 7 U.S. dead and missing, only one of the missing, USMC Corporal Frank Cius, was released on 5 March 1973 as part of Operation Homecoming. More than 40 Nùngs were also killed or missing. Black year – 1968 For MACV and SOG, 1968 was a black year. The year saw the Tet Offensive, the largest PAVN/Viet Cong offensive thus far in the conflict, but the collapse of SOG's northern operations. Although the Tet Offensive was contained and rolled back, and significant casualties were inflicted upon the enemy, the mood of the American people and government had turned irrevocably against an open-ended commitment by the United States. For most of the year MACV-SOG's operations centered around in-country missions