Fuel starvation leads to forced landing of Cessna 172 during aerial photography

Casualties unknown • 16 h 20, FR

A pilot performing aerial photography in a Cessna 172 experienced engine power loss due to fuel starvation, resulting in a forced landing in a field near Les Herbiers.

What happened

On 15 October 2012, a Cessna 172M, registration F-GBFG, departed Lyon Bron airport for an aerial photography mission. The flight, which included the pilot and a passenger, was intended to cover a distance of approximately 400 to 450 nautical miles, with a planned refueling stop at Niort aerodrome.

After completing photography work near the commune of Les Herbiers, the pilot decided to divert to Cholet aerodrome, which was closer than the original destination. Shortly after this decision, the engine began misfiring and subsequently lost power. The pilot attempted to troubleshoot the issue before identifying a suitable field for an emergency landing. The aircraft landed approximately 15 NM from Cholet after a total flight duration of five hours and thirty minutes. There were no fatalities or injuries during the incident.

The investigation

The investigation focused on the pilot's fuel management and the aircraft's instrumentation. It was established that the pilot had estimated the aircraft's fuel autonomy using cruise performance tables, projecting a 6.5-hour flight time. This estimate was based on an average consumption of 29 l/h, providing a planned one-hour reserve.

Investigators found that the aircraft's fuel gauges were inoperative and permanently indicated that the tanks were full; the pilot was aware of this malfunction prior to departure. Furthermore, the pilot's consumption estimates did not account for the increased fuel usage caused by the maneuvers required for aerial photography, such as climbs and turns. Additionally, the pilot had set the fuel/air mixture to a rich position during lower altitude flight phases, which further increased fuel consumption beyond the predicted rates.

Findings

  • The primary cause of the engine power loss was fuel starvation.
  • The pilot's fuel management was imprecise due to an incorrect assessment of consumption during flight preparation, which failed to account for the extra fuel required for photography maneuvers.
  • The inoperative fuel gauges prevented the pilot from accurately monitoring remaining fuel levels.
  • The use of a rich mixture setting during certain flight phases contributed to higher-than-expected fuel consumption.

Probable cause

The engine failure was caused by fuel starvation resulting from an inaccurate estimation of fuel consumption during flight planning, compounded by the inability to monitor fuel levels due to inoperative gauges and increased consumption from aerial photography maneuvers.

Frequently asked questions

What happened in the 2012-10-15 aircraft accident near 16 h 20, FR?

A pilot performing aerial photography in a Cessna 172 experienced engine power loss due to fuel starvation, resulting in a forced landing in a field near Les Herbiers.

What aircraft was involved and where did it happen?

The accident on 2012-10-15 involved a aircraft, registration F-GBFG, at 16 h 20, FR.

What was the probable cause of the accident?

The engine failure was caused by fuel starvation resulting from an inaccurate estimation of fuel consumption during flight planning, compounded by the inability to monitor fuel levels due to inoperative gauges and increased consumption from aerial photography maneuvers.

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