An investigation has been launched as to why a Qantas jet was cleared to cross Sydney Airport’s main runway while another aircraft was landing, amid reports of staffing woes in the air traffic control tower. An investigation has been launched as to why a Qantas jet was cleared to cross Sydney Airport’s main runway while another aircraft was landing, amid reports of staffing woes in the air traffic control tower. It is believed air traffic control cleared the Boeing 737 — flight number QFA124 — to cross a runway moments after the QantasLink flight QLK424D had touched down on the same runway. “Air traffic control. A Qantas spokesperson confirmed both aircraft were cleared to proceed following instructions from air traffic control.