Definition of let down in English:

let down

phrasal verb

  • (of an aircraft or a pilot) descend prior to making a landing:

    ‘over the harbour, I started to let down’
    • ‘Within the hour, we were letting down for a landing at Casablanca on the Atlantic coast of Morocco.’
    • ‘It was a beautiful sunny afternoon and I was letting down over the Adriatic heading southward.’