What happened
On July 18, 2008, a Mooney M 20E was conducting a visual flight rules (VFR) flight from Stade to Porta Westfalica. The aircraft departed at 09:27 local time, maintaining a course of approximately 200° at altitudes between 700 ft and 800 ft MSL. At approximately 10:09, the aircraft collided with the northern side of the Wiehengebirge ridge at the main crest. The impact and subsequent impact with the terrain caused a post-crash fire that destroyed the fuselage and cockpit. The collision resulted in two fatalities, involving the pilot and one passenger.
Witnesses observed the aircraft flying at a low altitude beneath a cloud layer. One observer noted the aircraft flying approximately 250 meters away before it disappeared into the clouds located just ahead of the ridge edge. Shortly after the impact, parts of the tail section and engine were found scattered near the main wreckage site.
The investigation
The BFU investigation examined radar data provided by DFS, GPS data from a Garmin GPSmap 296 carried on board, and meteorological records. The investigation also reviewed the pilot's flight preparation and the weather information available at the time of departure. The aircraft was equipped with a portable GPS unit set to "Direct To" Porta Westfalica, which featured a terrain warning function set to a 500 ft caution elevation.
Radio communications were also reviewed. Before the accident, the pilot had contacted the Porta Westfalica tower to report his position near Bückeburg. The controller provided landing information, noting that the only available route to the airfield was through the gap in the mountains between the Wiehengeb and Wesergebirge ranges due to the prevailing weather.
Findings
- Low cloud ceilings: At the time of the accident, the cloud base was between 700 ft and 1,000 ft MSL, which placed the terrain of the Wiehengebirge ridge directly within the cloud layer.
- Inadequate flight preparation: The pilot had not sought individual flight weather briefings from the German Meteorological Service (DWD) for the specific route.
- Hazardous weather conditions: Significant weather warnings (AIRMETs) and GAFOR advisories were active, indicating low visibility and low cloud ceilings (X-RAY conditions) in the area.
- Terrain collision: The aircraft was flying at an altitude (700–800 ft MSL) that coincided with the level of the cloud base and the height of the ridge crest.