Wrong parts and poor maintenance caused the landing gear to jam on a training flight in Nelson, an investigation has found.
The aircraft was substantially damaged during landing in Nelson Aerodrome on May 11, 2011, but neither of the two pilots on board were injured.
A Transport Accident Investigation Commission report released today said the Piper PA31-350 Navajo Chieftain had a history of landing gear defects, and some of the earlier problems had been fixed using incorrect parts and unauthorised repair work.
The aircraft, owned and operated by air2there, was being flown by a flight examiner and a pilot being assessed for competency.
They were simulating an engine failure during approach to Nelson when the landing gear "unsafe" light was illuminated.