11 fatalities

2014-07-05: Piper PA-31-310 Navajo (N11WB) — Omega Skydiving School — Częstochowa-Rudniki, Poland

Częstochowa-Rudniki, PolandTakeoff (climb)

On July 5, 2014, a Piper PA-31-310 Navajo (registration N11WB) operated by Omega Skydiving School was involved in an aviation accident near Częstochowa-Rudniki, Poland during takeoff. 11 people were killed. Investigators recorded the probable cause as: The failure of the left engine's crankshaft caused an unfeathered propeller and asymmetric thrust, leading to a stall and subsequent crash. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781193512Data APIEditorial standards

A twin-engine aircraft crashed into a wooded area near Częstochowa-Rudniki Airport following engine failure during its initial climb, resulting in ten fatalities.

What happened

During a series of skydiving operations at the Częstochowa-Rudniki Airport in Silesia, a twin-engine aircraft departed from runway 26C carrying one pilot and 11 skydivers. Shortly after takeoff, while maintaining an altitude of approximately 100 meters, the aircraft experienced mechanical issues with its engines. The pilot notified the passengers of an emergency and attempted to perform an emergency landing.

During this maneuver, the aircraft experienced a significant left roll, reaching an angle of 70 degrees. This led to an aerodynamic stall, causing the plane to crash into a nearby forested area where the wreckage ignited. The impact occurred roughly 4,200 meters beyond the end of the runway. The accident resulted in 9 fatalities among the occupants, with three passengers sustaining serious injuries. Following the initial event, two of the survivors later succumbed to their wounds.

Findings

Investigations into the accident revealed that the aircraft was being operated without a valid Certificate of Airworthiness. The primary sequence of failure began when the left engine's crankshaft failed, which subsequently caused the propeller to malfunction; because the propeller could not be feathered, the resulting asymmetric thrust led to the stall.

Several contributing factors were identified regarding the right engine's transmission, specifically damage to the pin clutch connecting the crankshaft to the drive shaft. This damage may have resulted from a prior undocumented propeller strike or long-term fatigue from uneven engine operation. Additional findings included:

  • Inadequate maintenance of the aircraft
  • Use of fuel that did not meet manufacturer specifications
  • Unauthorized modifications that violated the aircraft's Type Certificate
  • Low power output from the left engine due to improper operation
  • High ambient temperatures during the flight

Probable cause

The failure of the left engine's crankshaft caused an unfeathered propeller and asymmetric thrust, leading to a stall and subsequent crash.