服務日期起始時間從 08:57 出發於 2026年9月9日預定出發顯示 21公車行程至預定觀察到X442Heathrow Terminal 509:00—X442Heathrow Terminal 509:30—X442Heathrow Terminal 510:00—X442Heathrow Terminal 510:30—X442Heathrow Terminal 511:00—X442Heathrow Terminal 511:30—X442Heathrow Terminal 512:00—X442Heathrow Terminal 512:30—X442Heathrow Terminal 513:00—X442Heathrow Terminal 513:30—X442Heathrow Terminal 514:00—X442Heathrow Terminal 514:30—X442Heathrow Terminal 515:30—X442Heathrow Terminal 516:00—X442Heathrow Terminal 516:30—X442Heathrow Terminal 517:00—X442Heathrow Terminal 517:30—X442Heathrow Terminal 518:00—X442Heathrow Terminal 518:30—442Heathrow Terminal 518:56—X442Heathrow Terminal 520:00—預定和觀察到的數值分開保存。當缺少特定站點的即時觀察時，BustimeFinder 不會捏造即時出發。