Incident Overview
On July 10, 1975, a Robin DR 400/180 with registration HB-EXG was involved in an accident near Härkingen, Switzerland. The pilot and his father were on board for a local VFR flight from Triengen/LU. During the approach to a selected field at Usserdorf, the aircraft struck a barley field with its left wing before coming to rest after a 40-meter slide.
Investigation Findings
The investigation revealed that the engine was functioning normally, and oil levels were within specifications. The pilot reported that the oil pressure gauge read zero, prompting an emergency landing. However, post-accident analysis indicated that the pilot had likely confused the oil pressure instrument with an unconnected fuel level indicator mounted on the dashboard. This extra gauge, intended for an auxiliary tank not present in this aircraft, remained at zero and had previously caused confusion.
Contributing Factors
The report identified several contributing factors to the accident. These included the failure to cover or remove the non-functional instrument, insufficient technical briefing on the specific aircraft type, and the pilot's limited flight experience. Additionally, the decision to shut down the engine during the landing approach eliminated the possibility of correcting a low approach path.