What happened
On August 8, 2020, a Cessna U206A (registration OH-CSU) was performing its fifth jump flight of the day at Imola aerodrome. The aircraft was carrying the pilot and five skydivers. During the takeoff roll on runway 19, the pilot applied full power and attempted to rotate the aircraft at approximately 70 mph.
While the aircraft did lift off from the runway, it failed to climb effectively. The airspeed dropped to between 60 and 65 mph, and the aircraft could not clear the trees located at the end of the runway. Realizing the climb was insufficient, the pilot decided to abort the takeoff and attempted an emergency landing on the grass area to the right of the runway.
The aircraft descended at a high rate of sink, struck the main landing gear, and bounced. The nose then dropped, and the aircraft struck the ground nose-first. The nose wheel dug into the soft ground, causing the aircraft to cartwheel onto its back on the left wingtip and nose. The pilot was left hanging upside down in the harness, while the skydivers managed to exit through the jump door after it was partially opened by a crew member.
The investigation
The investigation examined the aircraft's performance, the engine specifications, and the environmental conditions. Investigators reviewed engine data, which showed the Continental IO-520-A engine was functioning normally. The investigation also looked into the aircraft's loading, noting that the takeoff mass of 1604 kg was higher than the pilot's previous flights that day.
Discrepancies were noted regarding the engine's documented performance. While the aircraft's manual and records indicated an IO-520-A engine, there was confusion among the club's pilots regarding the exact engine type and its specific performance characteristics, as previous engine replacements had occurred. Additionally, the investigation reviewed the takeoff procedures used, specifically the use of flaps and rotation speeds.
Findings
- The primary cause of the accident was that the takeoff was performed at an insufficient airspeed.
- The pilot rotated the aircraft at a speed lower than the procedures recommended in the aircraft's manual.
- High ambient temperatures and calm winds, combined with a higher takeoff mass compared to earlier flights, negatively impacted the aircraft's climb performance.
- There was ambiguity regarding the engine's performance capabilities among the operators due to inconsistent documentation following engine changes.
- The use of flaps during takeoff was not recommended by the operators' own procedures, yet they were deployed during this event.