runway threshold

基本解释

Witnesses said that the aircraft apparently impacted a Fed-Ex semi truck traveling on U. S. 131 just a short distance from the runway threshold.
目击者称，貌似飞机撞到了一辆行驶在131号公路上得半挂卡车，当时卡车位于跑道入口附近。
IS the parenthetical figure following DH, DA or MDA which, when added to the touchdown zone, runway end, or threshold elevation, will give the DH, DA or MDA in feet above mean sea level.
决断高度或最低下降高度后括号中的数值。它与接地区、跑道顶端、或跑道头标高相加后即是决断高度（DA，DH）或最低下降高度（MDA）高于平均海平面英尺数。