What happened
On November 14, 2013, a group of eight Cessna 172 aircraft departed from Varaždin Airport to perform a specialized mission involving the aerial dispersal of bait for fox vaccination. The flight group was operating over western Slavonia, specifically covering the Pakrac and Jablanac areas.
During the mission, the flight leader eventually ordered all aircraft to return to the departure airport due to deteriorating weather. However, the aircraft with registration YU-DPR continued its mission. While flying near the Pakrac area, the aircraft disappeared from air traffic control radar at 10:01:30.
Following the disappearance, another aircraft in the group was directed to assist in the search. The wreckage and two occupants—the pilot and a technician—were located later that day near Gornji Rogolji. The pilot sustained serious injuries, while the technician suffered minor injuries.
The investigation
The AIN investigation examined the meteorological conditions, flight logs, and the aircraft's GPS data. Investigators found that the aircraft was flying at an altitude between 378 and 704 meters. At the time of the accident, the cloud base was approximately 600 meters, meaning the hilltop where the crash occurred was obscured by clouds.
Analysis of the GPS data showed that the aircraft was in a slight climb near the time of impact. The pilot stated that they had spotted trees from a distance and believed they could clear them; however, upon striking the trees, the aircraft was pulled downward by the impact.
Findings
- The primary cause of the accident was flying in unfavorable meteorological conditions, specifically operating below the prescribed VFR (Visual Flight Rules) minimums for visibility and cloud clearance.
- At the time of the accident, visibility at the nearby Gorice station was between 0.8 km and 1.5 km, and the sky was covered by Stratus nebulosus clouds.
- The pilot likely misjudged the height of the treetops due to the low cloud base and poor visibility.
- The operator's training program at the time did not sufficiently cover decision-making regarding changing weather conditions or flying over hilly terrain.