What happened
On June 23, 2018, a Cessna 208B Caravan, registration SP-KON, was conducting a skydiving mission near Chrcynno (EPNC) airport. The aircraft was carrying ten skydivers, four tandem passengers, and an observer. During the third flight of the day, the pilot was maneuvering the aircraft toward the drop zone at an altitude of approximately 4,000 meters AGL.
As the pilot prepared for the drop, the airspeed decreased below 90 knots. The pilot deployed the flaps to the 10-degree position and reduced engine power to approximately 30%. At this moment, the pilot signaled for the door to open, causing three skydivers to shift toward the rear of the cabin. While the pilot was focused on the GPS coordinates for the drop zone and flying within a cloud layer that obscured the natural horizon, the aircraft's stall warning activated.
In an attempt to regain altitude, the pilot increased engine power while maintaining a back-pressure elevator position. The resulting engine torque, combined with the high angle of attack, caused the aircraft to enter a right-hand spin. Due to the sudden onset of the spin, the skydivers at the door were ejected, and the remaining occupants exited the aircraft in an emergency fashion. The pilot managed to recover the aircraft at approximately 3,000 meters AGL and subsequently landed safely at the departure airfield.
The investigation
The PKBWL investigation examined the pilot's training, the aircraft's technical condition, and the environmental factors present during the flight. The investigation reviewed cockpit footage recorded by the skydivers and analyzed meteorological data. The investigators also reviewed the aircraft's maintenance logs and the pilot's flight experience, noting that while the pilot was experienced in skydiving operations, they had no practical experience in recovering from a spin.
Findings
- The primary cause of the incident was the pilot's incorrect response to the stall warning, specifically increasing engine power while maintaining a high angle of attack instead of reducing the angle of attack.
- The use of 10-degree flaps instead of full flaps increased the stall speed, a factor the pilot failed to account for.
- The movement of three skydivers toward the rear of the aircraft likely shifted the center of gravity aft, contributing to an increased angle of attack.
- Flying above a cloud layer resulted in a lack of a natural horizon, which, combined with the pilot's focus on the GPS, hindered situational awareness.
- The aircraft was found to be in a fully airworthy condition with all maintenance up to date.