Glider Stall During Forced Landing Near Schänis

Casualties unknown • Schänis Flugplatz (LSZX), SG, CH

A student pilot experienced a stall and subsequent crash while attempting an outlanding to avoid power lines near Schänis, Switzerland.

What happened

On August 14, 1967, a Rhönlerche II glider, registration HB-807, was involved in an accident approximately 400 meters southeast of the Schänil airfield. The pilot, a student with approximately six hours of total flight experience, was conducting a training flight under instructions to limit the duration of the flight and terminate soaring at a specific altitude.

After releasing from a tow at 600 meters, the pilot attempted to find rising air near Ziegelbrücke but failed to locate any lift. As the aircraft's altitude dropped to 350 meters, the pilot realized the airfield could no longer be reached. During the return attempt, the pilot encountered a high-voltage power line crossing the approach sector. To avoid the obstacle, the pilot attempted an outlanding in a nearby field by executing a right-hand turn to fly parallel to the lines. During this maneuver, the aircraft's airspeed dropped to approximately 50 km/h, and the pilot applied back-pressure on the control stick, causing the aircraft to stall and spin over the right wing. The glider struck the ground at a steep angle.

The investigation

The investigation examined the flight conditions, the pilot's experience, and the aircraft's mechanical state. The Rhönlerche II was found to be airworthy, with no evidence of mechanical failure contributing to the accident. The investigation noted that the pilot's decision to return to the airfield was made too late, leaving insufficient altitude to clear the power lines. Furthermore, the investigation established that the pilot was flying at the aircraft's minimum steady flight speed during the critical maneuver.

Findings

  • The pilot's decision to initiate the return to the airfield occurred too late in the flight.
  • The pilot attempted an outlanding to avoid a high-voltage power line that obstructed the approach path.
  • The aircraft was flying at its minimum airspeed during the turn.
  • The application of back-pressure on the control stick during the turn induced a stall.

Probable cause

The accident was caused by the student pilot's delayed decision to return to the airfield, which necessitated an emergency outlanding to avoid power lines; during this maneuver, the aircraft's speed dropped to the minimum threshold and a control input induced a stall at a low altitude.

Frequently asked questions

What happened in the 1967-08-14 ALEXANDER SCHLEICHER OHG SEGELFLUGZEUGBAU RHÖNLERCHE II accident near Schänis Flugplatz (LSZX), SG, CH?

A student pilot experienced a stall and subsequent crash while attempting an outlanding to avoid power lines near Schänis, Switzerland.

What aircraft was involved and where did it happen?

The accident on 1967-08-14 involved a ALEXANDER SCHLEICHER OHG SEGELFLUGZEUGBAU RHÖNLERCHE II, registration HB-807, at Schänis Flugplatz (LSZX), SG, CH.

What was the probable cause of the accident?

The accident was caused by the student pilot's delayed decision to return to the airfield, which necessitated an emergency outlanding to avoid power lines; during this maneuver, the aircraft's speed dropped to the minimum threshold and a control input induced a stall at a low altitude.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/405.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.

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