While flying at 350 feet, during a final test line run for a geo-survey operation, the pilot of a Cessna 210 transmitted a distress message stating that the aircraft's engine had failed. The pilot conducted a forced landing in a nearby field. He later reported that he had selected an alternative fuel tank in an unsuccessful attempt to restart the engine prior to conducting the forced landing.
In consultation with BASI, an assessment of the aircraft fuel quantity and engine condition was carried out by a representative of the aircraft's insurer. This assessment indicated that the aircraft's fuel quantity had been approximately 70 L in the left tank and nil detectable fuel in the right. The examination of the engine revealed no identifiable problems that could have contributed to the engine failure.
The aircraft was fitted with long-range fuel tanks. The pilot reported that the refuelling operation had been carried out on a sloping surface and therefore, the aircraft may not have been laterally level. He was aware that there was a 'Caution' in the aircraft flight manual which stated that, 'indication errors of up to 14 gallons [53 L] per tank may result from a one-degree lateral deviation from level'.
The reason for the reported engine failure could not be determined.