The purpose of the flight was to deliver the aircraft to its new owner. The aircraft had been imported from Papua New Guinea in December 1985 and had flown only a limited amount since that time. The pilot carried out three circuits prior to departure, and made a successful landing enroute for refuelling. However, on touchdown at Bankstown following a normal approach, the nosegear collapsed. Initial investigation revealed that the nosegear downlock had not completed its travel to the overcentre position. In addition, the microswitch was incorrectly adjusted, giving a down and locked indication before the lock was fully engaged. The nosegear had collapsed because of faulty rigging of the gear, which prevented it from completing the full extension cycle. The applied loads had been held by the actuating rods and bellcranks until a bellcrank rod end had failed in overload.