A plane crash at the Hawke's Bay Airport, from which two people walked away unscathed, is under investigation by the Civil Aviation Authority (CAA).
A CAA spokesman said the "occurrence", on Sunday, had been reported to them.
"[It was done] in line with the operator's requirements under Part 12 of the Civil Aviation Rules, and has been assigned to one of our Safety Investigators for investigation."
The light plane, named Wichita Girl, upended in a Sunday afternoon wind gust at Hawke's Bay Airport while it was in Napier for the Art Deco Festival.
The biplane was flipped on its back on one of the airport's grass runways.
Police, fire and ambulance services were called to the airport at midday, with the airport's own rescue services already alongside the aircraft, one of two World War II Boeing Stearman trainer craft.
Photographer Mike Gannaway was a spectator at the event and watched the plane coming in to land when it flipped.
"[The pilot] was looking pretty much in control, dropping over the fence as they do to land on the grass runway.
"He was doing a beautiful job, nicely coming in for landing. It looks like he went to touch down and one wing went downwards, he tried to correct and it went the other way and the whole plane flipped over."
Onlookers said the pair "slithered from the plane" and suffered only minor injuries.