常風行動
Reports came in from the outskirts of the city that the PAVN were closing in. At 10:48 a.m., Martin relayed to Kissinger his desire to activate Operation Frequent Wind, the helicopter evacuation of US personnel and at-risk Vietnamese. At 10:51 on 29 April, the order was given by CINCPAC to commence Operation Frequent Wind. The American radio station began regular play of Irving Berlin's "White Christmas", the signal for American personnel to move immediately to the evacuation points.