Introduction
On 25 June 2016, at 15:11 local time, a Piper PA-28-181, registration HB-PDH, operated by beltec.aero GmbH on a private flight, landed short of runway 25 at Schaffhausen Airport (LSPF). The pilot and three passengers were uninjured. The aircraft sustained minor damage.
Accident Sequence
The pilot planned a sightseeing flight with three passengers, intending to land at Speck-Fehraltorf for a hangar inauguration. Due to approaching thunderstorms from the south and west, the pilot decided instead to conduct a local flight to Lake Constance. Preflight checks and takeoff from runway 25 were normal. During the eastbound departure, the pilot observed cumulus clouds and light turbulence. After turning over Lake Untersee, a threatening black cloud wall was seen to the west, prompting an immediate return to Schaffhausen. Over Neuhausen/Rheinfall, the front-seat passenger noted that plants in fields were moving, indicating strong wind.
The approach was straight-in to runway 25, initially at 80 KIAS, then with flaps at 10° and speed at 64 KIAS. The pilot could see the runway despite increasing and heavy rain; a dark, opaque rain wall was slightly west of the airport. Due to turbulence and gusts, the stall warning sounded several times; the pilot adjusted power to maintain 64 KIAS. About 50 meters before the runway threshold, the aircraft was abruptly pushed down and landed in a tall rapeseed field. The engine was producing power until propeller contact, then stopped. The aircraft slid approximately 35 meters and turned about 70° to the left. Pilot and passengers were secured only with lap belts.
Meteorological Information
A MeteoSwiss weather forecast for the afternoon of 25 June 2016 predicted widespread thunderstorms, with visibility in heavy precipitation of 1–3 km. Weather records show that between 15:12 and 15:20, a strong rain front passed over Schaffhausen, with a mean wind of 52 km/h and gusts up to 89 km/h.
Aircraft Information
The Piper PA-28-181 aircraft flight manual specifies a normal approach speed of 66 KIAS with full flaps (40°). It recommends an increased speed and reduced flap setting in strong or gusty winds. The manual also requires the use of shoulder harnesses during approach and landing.
Conclusion
The choice of airspeed on final was not adapted to the gusty wind conditions. Consequently, HB-PDH landed in the rapeseed field before the runway.