What happened
On November 7, 2013, a Cessna C 177RG, registration OK-ONE, performed an emergency landing in a field near the village of Mostek u Chocně. The aircraft was operating a private flight itinerary involving several Czech aerodromes, including LKZA, LZKS, and LKLT.
After departing from the area of Pardubice (LKPD), the pilot noticed the engine began running irregularly. The pilot reported the situation to air traffic control, and the engine eventually ceased functioning entirely. Faced with a total loss of power, the pilot elected to perform an emergency landing in a field near the intersection of roads II/312 and Hemže. To mitigate damage, the pilot performed the landing with the landing gear retracted. The aircraft slid for approximately 54 meters, resulting in a deformed propeller and damage to the lower fuselage, though no injuries were reported.
The investigation
The ÚZPLN investigation focused on the engine failure and the accuracy of the aircraft's fuel monitoring systems. Investigators examined the pilot's flight planning, the aircraft's maintenance records, and the fuel levels at the time of the incident.
Technical inspections revealed that while the fuel caps were secure, there was no fuel remaining at the bottom of the tanks. A subsequent controlled refueling test conducted during repairs demonstrated that the cockpit fuel gauges provided highly unreliable readings. Specifically, when the aircraft was on its wheels, the gauges indicated significantly less fuel than was actually present, leading to a discrepancy of approximately 70 liters during testing. Additionally, investigators found that a fuel drain valve was partially malfunctioning due to corrosion and debris, though they could not definitively prove that fuel had leaked through this valve during the flight.
Findings
- The primary cause of the incident was engine failure due to complete fuel exhaustion.
- The pilot's flight planning was based on an incorrect estimation of the available fuel volume.
- The cockpit fuel gauges were unreliable and provided inaccurate readings of the actual fuel remaining in the tanks.
- The pilot failed to re-evaluate the required fuel reserves for the final leg of the flight after experiencing increased flight duration due to heavy winds.
- The pilot reacted correctly to the engine failure by choosing an appropriate landing site and configuration, which prevented further damage to the aircraft.