Context: The first aircraft, a South African Beechcraft King Air 200, landed at the new airport on 15 September 2015, prior to conducting a series of flights to calibrate the airport's radio navigation equipment.

Question: What kind of aircraft was the first to land at the new airport?
Answer: South African Beechcraft King Air 200

Question: What date did the aircraft land at the new airport?
Answer: 15 September 2015

Question: What are they calibrating via test flights at the airport?
Answer: the airport's radio navigation equipment.