What happened
On 17 June 2021, a Diamond DA2,0-C1 with registration HB-SGI was involved in an accident at Birrfeld airfield. The pilot had completed a flight circuit around Switzerland, returning to Birrfeld after approximately 3 hours and 22 minutes of flight time. Upon landing on runway 08, the pilot attempted a touch-and-go maneuver. Shortly after the second takeoff, the engine failed, causing the aircraft to enter a left turn toward nearby fields. The aircraft struck a meadow 170 meters northeast of the runway threshold 26, resulting in serious injuries to the pilot and significant damage to the aircraft.
The investigation
The Swiss Transportation Safety Investigation Board (STSB) examined the wreckage, GPS data, and maintenance records. The investigation revealed that the engine had recently undergone a major overhaul, but the fuel flow had not been readjusted following the installation of the overhauled engine. This resulted in an actual fuel consumption of approximately 28 liters per hour, which was higher than the 24 liters per hour used in the pilot's flight planning.
Furthermore, the investigation found that the aircraft's fuel gauge was inaccurate at low levels, specifically showing approximately one-quarter of a tank even when the tank was completely empty. This discrepancy, combined with the pilot's reliance on the gauge rather than a manual dipstick check after landing, contributed to the oversight of the dwindling fuel supply.
Findings
- The engine failed because the fuel supply was exhausted.
- The fuel gauge showed an erroneously high level when the fuel was low.
- The engine's fuel consumption was higher than expected due to unadjusted fuel flow settings following an overhaul.
- The pilot did not critically evaluate the fuel gauge readings against the calculated flight endurance.
- The pilot's decision to execute a steep turn at low altitude during the engine failure led to a loss of control.