Two skydivers jumped from a plane shortly before it crashed into a line of trees.
The pilot of the Cessna aircraft also walked away without injuries.
It is believed the plane lost engine power as it was preparing to land at Parakai, near Helensville, around 12.15pm yesterday.
The Civil Aviation Authority is investigating the crash, and communications manager Mike Richards said it was possible the trees slowed the plane as it came down.
"Probably it reduced the velocity of the aircraft, and reduced the force of impact, so that was good luck," he said.
"(The pilot) has done a great job to walk away from that, he really has."
Tandem skydivers had jumped out of the plane moments before, and the pilot was returning to the airfield when the incident occurred.
A CAA investigator at the scene reported the aircraft sustained "quite severe damage" from the crash.
The authority will take the wreckage to a secure location for examination.
Tony Moore, a director of Blueskies Skydiving, confirmed his company used the plane. The company was conducting a debriefing about the incident yesterday afternoon, he said.
"Fortunately the pilot is fine and there were no skydivers from our company in the air when the crash happened," Moore added.