What happened
Between 2000 and 2009, the Finnish Safety Investigation Authority (OTKES) conducted a systematic review of 20 investigations involving Class B ultralight aircraft. The study was prompted by a notable increase in ultralight accidents in Finland during 2009. The research analyzed various incidents, including accidents involving aircraft such as the Eurostar EV-97, Ikarus C42, and Dynamic WT-9, ranging from minor damages to fatal crashes.
In one specific analyzed case (B6/2009L), an aircraft impacted the ground with its engine still running. The investigation established that the aircraft entered a stall during a technically demanding turning maneuver at a low altitude. Due to the low height, the pilot was unable to recover from the stall once it occurred.
The investigation
OTKES utilized the SHELL model to analyze the human factors contributing to these events. The investigation scope was limited to B-category ultrallight aircraft accidents, damages, and serious incidents investigated by the authority between 2000 and 2009. The methodology involved a systematic analysis of 20 investigation reports, supplemented by interviews with investigators and archival research. The study also evaluated the effectiveness of safety recommendations and compared Finnish investigation practices with those in other European nations.
Findings
Limited pilot experience was identified as a contributing factor in the majority of the analyzed events. Specifically, in nearly half of the cases, inadequate flight skills and the selection of unsuitable procedures played a role. In one-quarter of the studied cases, the immediate cause of the incident was an aircraft stalling at low altitude, where the pilot failed to recognize the onset of the stall.
Other contributing factors identified include:
- Inadequate flight training and insufficient pilot training regarding cockpit instrument usage.
- Deficiencies in aircraft construction, maintenance, or manufacturing.
- Improper aircraft loading (overweight conditions).
- Inadequate flight manuals and instructional guidance.
- Unfavorable weather conditions and poor monitoring of airspeed.
- A training culture that encouraged high-risk maneuvers, such as performing turns at very low altitudes during engine failure simulations.
Safety action
Following the investigations, several safety recommendations were issued to various authorities. These included requests for the Finnish Civil Aviation Authority (Trafi Ilmailu) to clarify regulations regarding instructor qualifications and to implement measures to prevent overweight operations. Recommendations were also made to the Finnish Aero Club (SIL) to refine training programs with specific safety limits and learning objectives, and to improve coordination between emergency services and rescue centers.