What happened
On May 25, 2016, a Piper PA-28-180 Archer, registration F-BVVY, departed from Nancy-Essey for Nantes-Atlantique, carrying a student pilot and an instructor. Shortly after takeoff, the crew performed a turnaround due to intermittent VHF radio malfunctions. Once the radio equipment began functioning again, the crew decided to proceed with the flight, traveling alongside a TB10 aircraft.
During the flight, the radio issues recurred, necessitating that the crew rely on the TB10 pilot to handle communications with air traffic control. While approaching Nantes-Atlantique, the aircraft was placed in a holding pattern due to heavy IFR traffic. During the final approach on the downwind leg for runway 03, the engine stopped. The instructor managed to land the aircraft safely on the runway.
The investigation
The investigation focused on the fuel management and the circumstances leading to the engine shutdown. The instructor had planned the flight with an estimated fuel consumption of 35 L/h, believing they had sufficient reserves. However, the actual consumption was calculated to be approximately 43 L/h. This discrepancy was attributed to several factors, including the absence of wheel fairings, which can increase drag, and the additional flight time caused by the initial turnaround.
Investigators also examined the fuel quantity estimation. The instructor used a wooden dipstick to estimate the fuel levels at departure, adding 50 liters to the tanks. The crew had also arranged to refuel at the destination, as the flight was part of a ferry mission for a TB10 aircraft. Furthermore, the instructor noted that potential diversions were difficult because strikes at refineries and ports had made fuel availability uncertain at other aerodromes.
Findings
- The engine shutdown was caused by insufficient fuel remaining in the tanks.
- The instructor underestimated the aircraft's hourly fuel consumption during flight planning.
- The initial radio malfunction and subsequent turnaround increased the total flight duration by approximately 30 minutes.
- The decision to continue toward the destination was influenced by the lack of available fuel at alternative aerodromes due to local industrial strikes.
- The crew's reliance on the TB10 for communications and the specific mission objectives contributed to the decision-making process regarding fuel reserves.