What happened
On August 19, 2012, a Cessna C2/08B Supervan 900 was conducting parachute jump operations over the Poznań-Bednary (EPPB) landing field. The aircraft was carrying one pilot and 17 skydivers/tandem passengers. During the jump phase, as the pilot attempted to level the aircraft at 4,000 meters and reduce speed, a malfunction occurred in the engine power control system. This malfunction prevented the pilot from reducing the aircraft's airspeed.
While the initial jumpers exited the aircraft within the speeds specified in the Flight Manual, the pilot had to maintain a higher speed for the remaining jumpers. To prevent a jumper from colliding with the horizontal stabilizer, the pilot maintained level flight rather than a climb. Consequently, the final jumpers exited the aircraft at 100 knots, exceeding the recommended jump speed range of 75 to 85 knots. All passengers landed safely at the Poznań-Bednary field.
Following the jump, the pilot consulted with the jump master and decided to divert to the nearby controlled airport, Poznań-Ławica (EPPO), to utilize its superior emergency services. The descent was conducted gradually without exceeding maximum speeds, and two-way communication was maintained with Poznań Approach. Prior to the final approach, the pilot notified air traffic control of the intention to shut down the engine on the straight-in leg. The engine was subsequently shut down, and the propeller was set to the feathered position. The aircraft landed safely at EPPO without damage to the airframe or injuries to the occupants.
The investigation
An inspection of the propulsion system by the investigation team revealed a fracture in a rigid component of the engine power control linkage. The investigation established that the fracture was a fatigue failure. The mechanism of failure involved the bending of the control linkage whenever the power lever was moved to its forward-most position. Over time, this repeated bending induced fatigue, resulting in the structural failure of the rigid element and the subsequent loss of power control capability.