A Rotorua student pilot who was killed in a crash on Saturday had finished a flight lesson shortly before his plane hit the ground.
Emergency services were called to the scene at Earthquake Flats Road in Waikite Valley, south of Rotorua, just before 1.30pm.
Police were yet to publicly identify the 27-year-old man.
Civil Aviation Authority (CAA) spokesman Mike Richards said the man had just finished a flying lesson and had taken off on his own.
"He literally finished a dual operator instructor lesson, which was a fairly extensive one, and then flew off on his own pretty close to the conclusion of that lesson, and unfortunately hit the terrain only about 200 metres away from the airfield."
There was a witness to the crash, who investigators were speaking with today, but Mr Richards said it was not known if it was the instructor.
He said the plane was a Fletcher 24 Turbine Engine kerosene, which was the kind often used in agricultural applications.
CAA inspectors were at the site on Sunday combing through the wreckage to try to find the cause of the crash, he said.
"They'll be looking for mechanical or equipment failure or ... any major part of the aircraft that might have dislodged."
The inspectors were taking video footage and digital images to analyse, he said.
"They also need to determine whether they need to take the wreckage away from the site, and if they do it will mean they need to examine it more closely in controlled conditions."
Mr Richards said it was still early days with the inquiry, but the CAA wanted to find out if there were any "key learnings" for the industry about mechanical or equipment failure or pilot error.
He said there might also be tips to pass on to instructors on how to teach their students.
"We're not there to apportion blame to anybody."