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ASN Wikibase Occurrence # 66418
Last updated: 10 January 2021
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Type:Tomark Viper SD-4
Registration: OM-M702
C/n / msn: 2
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Raznany, Sabinov -   Slovakia
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:LZRY
Destination airport:LZRY
Investigating agency: LNVU
Crashed during testing about 2km of the airport Raznany. 63yr old co-pilot died at the scene and 34yrs old pilot has been transported via air ambulance to the nearest hospital with life treatening injuries. He died few hours after the crash in hospital. The aircraft is believed to be written off. The pilot had deliberately steered the aicraft into a spin about 800 m above the ground and failed to recover the aicraft from it. The plane crashed after about 15 turns. The last few turns were flat ones after the pilot opened the canopy in a late attempt to bail out (both pilots were equipped with parachutes). The pilot was not authorized to attempt any spins that day. But he was encouraged do so after he had made some (unauthorised) successful spin recoveries solo the previous day.
The most probable cause of the pilot's failure to recover from the spin and subsequent crash was an thin electric cable on the leading edge of the vertical stabilizer, leading to a small camera installed at the top of the vertical stabilizer, intended to be used for the recording of an official spin recovery test, which was due to be carried out a few days later. The camera was installed by a person with poor understanding of aerodynamics and flight mechanics. The pilot and the co-pilot, although both very experienced, failed to recognize the grave risk posed by the camera cable on the leading edge of the vertical stabilizer during the pre-flight inspection of the plane. When the plane entered the spin, the cable most likely caused the separation of the boundary layer on the suction side of the stabilizer in an unsymmetrical airflow pattern. That resulted in a substantial decrease of the efficiency of the vertical stabilizer during recovery attempts, effectively preventing the pilot from recovering from the spin.
Electric Cabel ist not mentioned in Final Report.
Causes of the Accident /Final Report/: The crew did not perform sufficient preparation for the intended flight. Flight Activity on the day of an airplane accident was not carried out in accordance with the air regulations of the Slovak Republic. Accirding to the POH Viper SD-4, OM-M702 was intended for sport and recreational flying. The crew consciously introduced the aircraft into the non-standard flight mode of the right Spin to which the aircraft was not intended by the manufacturer. The crew failed to rcover the aircraft from the non-standard flight mode in the given weight configuration. MTOW was exceeded.

The crew did not perform sufficient preparation

Final Report:

Accident investigation:
Investigating agency: LNVU
Status: Investigation completed
Download report: Final report


OM-702 rec AC

crash site

Revision history:

15-Jul-2009 21:00 Martin Added
16-Jul-2009 02:44 Taildragger Updated
16-Jul-2009 20:57 Anon. Updated
17-Jul-2009 12:06 Martin Updated
17-Jul-2009 12:09 Martin Updated
22-Jul-2009 09:11 Hoplite Updated
19-Mar-2012 12:41 private investigator Updated [Source, Narrative]
03-Feb-2019 12:02 Anon. Updated [Source, Narrative]
03-Feb-2019 12:03 harro Updated [Departure airport, Destination airport, Accident report, ]

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