NORTH AMERICAN AT-6D near Oshkosh, WI — 2023-07-29
- Date
- 2023-07-29
- Location
- Oshkosh, WI, USA
- Airport
- OSH
- Aircraft
- NORTH AMERICAN AT-6D
- Registration
- N49961
- Category
- Airplane
- Highest injury
- Fatal
- Fatalities
- 2
- Phase of flight
- Maneuvering
Probable cause
The pilot’s failure to maintain airspeed while maneuvering, which resulted in the exceedance of the airplane’s critical angle of attack and an aerodynamic stall/spin.
NTSB narrative
The pilot and passenger departed on a local flight and climbed to an altitude of about 3,900 ft mean sea level (msl) while turning to overfly a local lake. After leveling off, the airplane made a turn to the right, followed by a turn to the left. Performance calculations based on ADS-B and winds aloft data showed that, during the turns, the airplane decelerated, and the calculated load factor increased. The airplane slowed to a speed consistent with its published accelerated stall speed, then entered a rapid descent. A witness reported seeing the airplane in a flat spin to the right that continued until the airplane impacted the water. The airplane was destroyed when it impacted the water. Examination of the airplane, engine, and related systems did not reveal any preimpact anomalies that would have precluded normal operation. Based on the available information, the pilot likely failed to maintain adequate airspeed while maneuvering and exceeded the airplane’s critical angle of attack, which resulted in an inadvertent aerodynamic stall/spin.
Analysis
- Primary failure mode
- Loss of control
- First missed decision gate
- Pilot could have avoided excessive maneuvers leading to loss of control.
NTSB coding
Evidence available
- ADS-B / radar
- 12 docket documents
Docket documents12
- AIRCRAFT PERFORMANCE PLOTSform
- RELEASE OF AIRCRAFT WRECKAGE, NTSB FORM 6120.15form
- RECORD OF FAA INTERVIEW OF WITNESSinterview
- AIRCRAFT EXAMINATION SUMMARYother
- AIRFRAME MAINTENANCE RECORD EXCERPTSother
- ENGINE MAINTENANCE RECORD EXCERPTSother
- FLIGHT MANUAL EXCERPTSother
- PILOT LOGBOOKother
- ADS-B DATAradar
- ADS-B DATA (KMZ FILE)radar
- GOOGLE EARTH PLOTS OF ADS-B DATAradar
- TOXICOLOGICAL REPORTreport
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