By 26 March, Huế and all of Quảng Trị, Thừa Thiên, Quảng Nam and Quảng Ngãi Provinces had been captured by the PAVN and Da Nang was isolated. General Trưởng organised his remaining forces, which numbered approximately 75,000 troops, into inner and outer defensive lines around the city, meanwhile the PAVN prepared to attack the city from four directions before its defenses could be properly established. Trưởng's defense plans were hampered by the presence of 1–1,500,000 refugess and ARVN stragglers who had crowded the city. Throughout 26 March evacuation flights by Air America, Air Vietnam, the RVNAF and World Airways from Da Nang AB took place but could not keep up with the vast tide of refugees. On 27 March the situation at Da Nang AB was becoming increasingly chaotic as panicked refugees surged to board a World Airways flight and began mobbing the other flights and gathering on the taxiways and runways. By the evening of 27 March all evacuation flights out of the base were stopped, but propeller aircraft continued to evacuate refugees from Marble Mountain Air Facility. That night General Lanh, Deputy Commander of the RVNAF flew into the base and instructed General Khanh the RVNAF 1st Air Division commander to evacuate all flyable aircraft, 130 aircraft would be evacuated while some 180, including 33 A-37s, were abandoned.