What happened
On April 21, 2010, a Robin DR 400-180 R acting as a glider tug departed from the unpaved runway at Chambéry Challes-les-Eaux for its first flight of the day. While climbing to approximately 1,700 meters, the pilot noticed a significant loss of engine power. The pilot subsequently instructed the glider pilot to release the towline.
Upon investigating the cause of the power loss, the pilot discovered that the main fuel tank was empty, while the auxiliary tank remained full. Although the pilot attempted to transfer fuel from the auxiliary tank to the main tank, the flow rate was insufficient to restart the engine. The pilot performed an emergency landing in a field previously identified by glider pilots for such purposes. There were no injuries and no damage to the aircraft.
The investigation
The investigation established that the fuel shortage was the result of a series of errors during refueling and pre-flight preparations. A few days prior to the incident, another pilot had refueled the aircraft. This pilot mistakenly filled the auxiliary tank instead of the main tank, likely due to the different fuel cap configurations between the Jodel D 140 and the DR 400.
On the day of the accident, the pilot of F-GEKY was managing glider operations alone at the club and proceeded to the aircraft with haste. During the pre-flight inspection, the pilot observed that one tank was full and the other was empty but failed to act on this information. Crucially, the pilot did not utilize the onboard checklist and failed to notice the low-level fuel warning lights on the dashboard.
Findings
- The primary cause of the engine failure was insufficient fuel checks before engine start and during the flight.
- A contributing factor was the incorrect selection of the fuel tank during the previous refueling session.
- The pilot's haste and failure to use the checklist prevented the detection of the empty main tank before takeoff.