What happened
On a flight conducted for the Hungarian Aerobatic Club, an Air Service Hungary (Repülögépes Szolgalat Allami Vallat) aircraft was performing a special mission from Budaörs to Dunakeszi. The flight was transporting seven passengers along with two pilots.
During the transit, the aircraft encountered weather conditions characterized by limited visibility. While navigating near the northern suburbs of Budapest, the single engine airplane collided with the terrain at Hármashatárhegy. The impact caused the airframe to break apart, resulting in nine fatalities and no survivors.
Findings
Investigations into the crash concluded that the primary reason for the accident was an incorrect altimeter setting, which led to the aircraft striking the mountain slope.