What happened
On 18 May 2019, a PZL Swidker PW-6U sailplane, operated by Cercle Européen de Vol à Voile, was conducting an introductory flight when it was forced to perform an out-landing in a field in the commune of Froidchapelle. The flight had originated from the Cerfontaine aerodrome, but the pilot determined the aircraft lacked sufficient altitude to return to the home airfield.
During the final approach to the chosen landing site, the pilot identified trees obstructing the approach path. An attempt to maneuver around these obstacles caused the aircraft to become unbalanced. Consequently, the left wing struck the ground first, leading to a hard impact and a ground loop. The aircraft sustained substantial damage, specifically to the nose section. The two occupants of the aircraft escaped with 2 minor injuries.
The investigation
The investigation established that the pilot was operating in a relatively new environment, as the club had recently relocated its activities to the Cerfontaine aerodrome. Meteorological conditions during the flight were favorable, with good thermal activity and high visibility.
Investigators identified a critical error in the cockpit instrumentation setup: the pilot had configured the altimeter using the barometric pressure at mean sea level (QNH) rather than the pressure at the airfield elevation (QFE). This discrepancy resulted in an altitude indication error of approximately 291 meters.
Findings
Several contributing factors led to the accident:
- The pilot made a delayed decision regarding the selection of the out-landing field.
- The pilot misjudged the terrain and configuration of the landing area, necessitating the avoidance maneuver.
- An incorrect altimeter setting (QNH instead of QFE) contributed to altitude miscalculation.
- The presence of trees in the approach path acted as a physical obstacle that triggered the loss of control.
Safety action
Following the incident, the training organization (FCFVV) committed to several safety improvements, including:
- Implementing a pre-takeoff checklist specifically designed to prevent confusion between QNH and QFE settings.
- Enhancing risk analysis procedures when operating in new environments.
- Providing refreshed training regarding the risks associated with out-landing, specifically focusing on terrain, obstacles, and surface conditions.