根據航空網站flightradar24的資料,CA428客機約於9時06分起飛,之後在近2800呎高空開始左轉,飛往大澳方向。當時空管人員指示機師立刻往右飛至航向270度,稱「Air China 428,Turn right immediately, Turn right immediately. Heading 270 Turning ahead expedite climb.」空管人員之後再召喚機師,然後提高聲線呼叫,指示對方小心前面地勢,要立即爬升至5000呎:「Air China 428, expedite climb, terrain ahead, terrain alert, expedite climb passing 5,000ft, expedite.」