(案例分析)某机组执行克拉玛依至阿克苏航班，由于乌鲁木齐区调指挥下降高度时机偏晚，当联系上阿克苏塔台时，此时进近的飞机都在减速调整落地间隔（阿克苏机场沥青道面且没有快速脱离道，落地后需滑行至跑道端掉头后脱离跑道），塔台指挥比较繁忙，机组连续呼叫申请下降高度而无应答，此时机组听到部分指令：“下场压高度1200米，起始点报。”当时飞机正飞向起始进近定位点，限制高度也是1200米。机组立刻调整高度开始下降，并同时向塔台证实指令。请问，机组操作是否正确？如果是你，应该如何处置？ （cases analysis）Once some crew performed flight from Karamay to Aksu. Because the timing of commanding to descent in Urumqi area was relatively late, and when crew contacting with Aksu tower, other aircraft performing approach were decelerating and adjusting landing separation (Aksu airport equipped with asphalt pavement without rapid exit way, thus aircraft need to taxi to the end of RWY and get rid of RWY after landing), the tower guidance was relatively busy, and crew continuously called ATC and applied for descent with no response. Meanwhile, crew heard some instructions: descend QFE 1200M, report at the IF. At this time, aircraft was flying directly to IF with an altitude limit of 1200m. Crew adjusted altitude and initiated to descend and ask for confirmation of instructions from tower control as well. Was is correct regarding crew operation? If you were they, how would you handle with it?