What happened
On July 4, 2016, an Airbus A202/15-1, registration HB-HFW, was performing a visual flight rules (VFR) flight from Salzburg to Innsbruck. While approaching Innsbruck airport, just before reaching the MIKE 3 reporting point, the pilot noticed the engine began running unevenly. In an effort to manage the situation, the pilot activated the booster pump and decided to perform a precautionary landing in a nearby field to avoid flying over populated areas. The pilot communicated this intention to the Innsbruck air traffic control service. During the final approach to the chosen landing site, the engine failed completely. The aircraft landed in a field; the occupants remained uninjured and the aircraft sustained no damage.
The investigation
The investigation was conducted by the Swiss Transportation Safety Investigation Board (SUST) following a delegation from the Austrian safety authority. Investigators examined the flight planning and fuel management of the crew. The pilot had planned a 65-minute flight with an additional 60-minute reserve. However, strong headwinds significantly extended the flight duration.
Further examination revealed that the pilot had extensive experience with a different aircraft of the same model that featured different fuel gauge characteristics. This led the pilot to believe that the remaining fuel levels were higher than they actually were.
Findings
- The primary cause of the engine failure was fuel exhaustion.
- The pilot relied on fuel gauges that provided an inaccurate representation of the actual fuel remaining in the tanks.
- Previous experience with a similar aircraft type with different gauge characteristics contributed to a miscalculation of available fuel.
- The pilot's decision to execute an immediate precautionary landing upon the first sign of engine irregularity was a safety-conscious action that prevented an accident over populated areas.