Airport spokeswoman Naomi Lindsay said the pilot radioed ground crew on approach.
"They weren’t sure how their landing was going to go.
"So we activated our usual emergency procedures and activated the emergency centre but we soon stood it down once they landed.
"They landed safely and are both OK."
The Queenstown and Frankton fire brigades, Queenstown police and St John were alerted as back-up to the airport’s crews but turned back before they had reached the airport, on Sir Henry Wigley Dr in Frankton.
Last night there was no information available on how the door came loose or where it landed. CAA has been approached for comment.
No scheduled passenger jet flights were disrupted by the incident, although two arrivals were cancelled and one was delayed by high winds around the same time.
