Glider landing accident in Kirchzarten caused by improper flap deployment

Casualties unknown • Kirchzarten, DE

A student pilot sustained minor injuries after an ASK 23 B glider experienced a sudden loss of altitude during landing following a tow rope failure.

What happened

On August 12, 2012, a student pilot was conducting training flights at the Kirchzarten glider airfield. Following two successful training flights in a different aircraft, the pilot attempted their first flight in an ASK 23 B glider. The flight began with a winch launch from runway 36 at 15:53 local time.

During the climb, at an altitude of approximately 120 to 150 meters, the tow rope snapped. The pilot managed to maintain level flight and initiated a 180-degree turn. The instructor, observing from the ground, confirmed that both the release path and the landing runway were clear for a landing toward runway 18.

The student pilot elected to land on the winch release path. During the final approach, at an altitude of approximately four to five meters, the pilot extended the landing flaps. The pilot reported being surprised by the significant aerodynamic effect, which caused the glider to suddenly sink. In an attempt to recover, the pilot retracted the flaps. This resulted in a series of hard landings, culminating in a final touchdown where the aircraft abruptly rotated 90 degrees to the left. The pilot sustained minor injuries, and the ASK 23 B was heavily damaged.

The investigation

The BFU examined the aircraft and the circumstances of the flight. The investigation confirmed that the aircraft, a fiberglass construction glider with 1,807 total flight hours, suffered significant structural damage. Specifically, the fuselage tube broke near the tail unit, the underside of the cockpit shell cracked, and the canopy frame was distorted with a tear in the locking mechanism fabric. The investigation also reviewed the pilot's training status, noting they were in the second stage of training and had received theoretical instruction for this specific model only one day prior to the accident.

Probable cause

The sudden loss of altitude and subsequent hard landings were caused by the pilot's improper deployment of the landing flaps at a very low altitude, which led to an unexpected sink rate.

Frequently asked questions

What happened in the 2012-08-12 Alexander Schleicher Segelflugzeugbau / accident near Kirchzarten, DE?

A student pilot sustained minor injuries after an ASK 23 B glider experienced a sudden loss of altitude during landing following a tow rope failure.

What aircraft was involved and where did it happen?

The accident on 2012-08-12 involved a Alexander Schleicher Segelflugzeugbau /, at Kirchzarten, DE.

What was the probable cause of the accident?

The sudden loss of altitude and subsequent hard landings were caused by the pilot's improper deployment of the landing flaps at a very low altitude, which led to an unexpected sink rate.

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