What happened
On August 27, 2017, a Cessna 207 Skywagon, registration D-EPJR, was conducting a skydiving flight at the "Madonna di Loreto" airfield. Following the deployment of parachutists, the pilot transitioned into a descent attitude and experienced a sudden hardening of the flight controls, which prevented the reduction of the descent rate. The pilot managed to maintain control by increasing propeller pitch to the maximum, though the aircraft experienced a rapid increase in airspeed.
As the aircraft descended to approximately 5,000 feet, the pilot regained control of the flight surfaces. However, at roughly 1,500 feet, white smoke and intense vibrations filled the cabin. Shortly thereafter, the engine ceased operation. The pilot declared an emergency and successfully performed an engine-out landing on Runway 36, coming to a stop near the middle of the runway.
The investigation
The ANSV investigation focused on the mechanical failure and the reported control difficulties. While investigators could not replicate the elevator control hardening on the ground, they noted small indentations on the elevator edges, though they could not confirm if an external object caused the issue.
An inspection of the Continental IO-520F engine revealed that the failure was caused by the rupture of connecting rod number 4, which had fragmented within the engine crankcase. GPS data from the onboard AvMap GeoPilot II confirmed a high-rate spiral descent with significant fluctuations in airspeed and vertical speed following the jump.
Findings
- The primary cause of the event was a technical failure involving the rupture of connecting rod number 4.
- High vertical and airspeed following the jump may have increased stresses on the engine, contributing to the failure.
- The cause of the temporary control surface stiffness remains undetermined, as it could not be reproduced during testing.