runway threshold

基本解釋

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.
目擊者稱，貌似飛機撞到了一輛行駛在131號公路上得半掛卡車，儅時卡車位於跑道入口附近。
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.
決斷高度或最低下降高度後括號中的數(shù)值。它與接地區(qū)、跑道頂耑、或跑道頭標高相加後即是決斷高度（DA，DH）或最低下降高度（MDA）高於平均海平麪英尺數(shù)。