What happened
On June 8, 2015, at approximately 13:00 LMT, a professional pilot arrived at the Strzyżewice airfield near Leszno to perform glider towing operations. The flight involved a PZL-104 Wilga 80 (registration D-ELSZ) configured for a two-glider tow sequence. After completing a pre-flight inspection, the pilot coordinated with a glider instructor to perform two climbs to 400 meters.
During the initial climb phase, at an altitude of approximately 50 meters AGL, the pilot observed fluctuating fuel gauge readings. Believing the aircraft was experiencing a fuel imbalance that might lead to engine failure, the pilot attempted to switch the fuel selector valve from the right tank to the left tank. During this manipulation, the pilot inadvertently pushed the control column forward, causing the aircraft to transition from a climb to a descent. Perceiving this as a loss of engine power, the pilot released the tow rope and attempted an emergency landing within the airfield boundaries.
As the aircraft descended, it lost airspeed and settled from a height of several meters. The impact caused the main landing gear struts to fail, specifically the detachment of the shock absorber mounting pins. This led to the gear resting directly on the ground, causing the aircraft to brake violently, slide approximately 14 meters, and ultimately undergo a nose-over (capsize).
The investigation
The PKBWL investigation focused on the pilot's actions during the climb and the mechanical failure of the landing gear. Investigators examined the fuel system, the pilot's pre-flight inspection, and the flight path. The investigation established that while the pilot believed the engine was losing power, the actual cause of the descent was the physical movement of the control column during the attempt to reach the fuel valve. Furthermore, the investigation reviewed the fuel logs, noting that the aircraft had been recently refueled and contained significantly more fuel than the pilot's gauge readings suggested.
Findings
- The primary cause of the capsize was the excessive sink rate and loss of altitude during the emergency landing.
- The root cause was the pilot's decision to manipulate the fuel selector valve during the critical initial climb phase.
- The pilot's attention was diverted from maintaining airspeed and heading to monitoring unreliable fuel gauges.
- An inadequate pre-flight inspection resulted in the pilot lacking accurate knowledge of the actual fuel quantity, relying instead on erroneous float-type gauge readings.
- The physical act of reaching for the fuel valve caused the pilot to inadvertently push the control column, inducing the descent.
- The landing gear failure was caused by the high-impact contact of the gear struts with the airfield surface during the sink.