Lodestar ZK-BMC was operating several topdressing sorties in the area of Bideford. On the morning of October 20, the plane departed at 05:15 on the first sortie of the day. The operation proceeded normally, each flight taking 17 to 18 minutes to complete. At 06:40 hours it was apparent that a front was approaching from the south. The pilot decided to carry out one more flight and departed Masterton at 07:00. The aircraft struck a hill 1,350 feet (410 m) amsl, 8 feet below the crest in drizzle and poor visibility. OPINION: “The cause of the accident was an error of judgment on the part of the pilot in electing to continue the flight in the face of deteriorating weather conditions, during which time the aircraft struck the top of the hill, while the pilot was attempting to maintain visual flight under instrument conditions.”