What happened
On June 25, 2016, a private flight departing from Schaffhausen Airport (LSPF) encountered deteriorating weather conditions. The pilot, originally planning a flight to Speck-Fehraltorf, opted for a local circuit around Lake Constance after observing developing convective clouds and turbulence. As the aircraft returned to the airfield, a heavy rain front moved into the area, accompanied by significant wind.
During the straight-in approach to runway 25, the pilot maintained an airspeed of approximately 64 KIAS with flaps set to position 1 (10 degrees). The pilot noted that the aircraft's stall warning activated several times during the final approach due to increasing turbulence and gusts. Approximately 50 meters before reaching the runway threshold, the aircraft was suddenly pushed downward, causing it to impact a high rapeseed field. The aircraft slid for about 35 meters and rotated 70 degrees to the left before coming to a stop. The impact resulted in light injuries to one passenger, while the pilot and the other two passengers remained uninjured. The aircraft sustained damage to the propeller, nose and main landing gear, and the right wing leading edge.
The investigation
SUST examined meteorological data and aircraft performance parameters. Records from MeteoSchweiz confirmed that a strong rain front passed over the airfield between 15:12 and 15:20, featuring sustained winds of 52 km/h and gusts reaching 89 km/h. The investigation also reviewed the aircraft flight manual (AFM) for the Piper PA-28-181, which recommends increasing approach speed and reducing flap settings when operating in strong or gusty winds. Additionally, it was noted that while the pilot and passengers were secured with lap belts, the use of shoulder harnesses is required by the AFM during approach and landing.
Findings
- The chosen approach speed was insufficiently high to account for the severe wind gusts and turbulent conditions.
- The aircraft encountered sudden downward vertical movement caused by the weather conditions, leading to the undershoot.