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CEN20CA326

2020-08-06 · St Louis, Missouri, United States · None · 1 aircraft · Status: Completed

Airport KSUS

Aircraft involved

Probable cause & findings

The flight instructor's failure to maintain helicopter control which resulted in a hard landing while preforming a practice autorotation.

Factual narrative

The instructor reported that during the instructional flight, he was manipulating the controls and accepted the option to land on the taxiway; he decreased the throttle for a full touchdown auto rotation. About 50 ft above the ground (agl), he flared the helicopter and leveled off about 5 to 10 ft agl. The instructor reported that everything seemed "normal" at this point. He then raised the collective, but the descent was not arrested, so he raised the collective full up. The helicopter landed hard and shook violently. The instructor closed the throttle to which stopped the fuel supply. The tailboom was substantially damaged. The flight instructor reported that there were no mechanical anomalies with the helicopter that would have precluded normal operation. The instructor added that he felt a slight tailwind after exiting the helicopter and that the tail wind caused a "vortex ring state" which stalled the main rotor blades. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

FAA avdata. C = Cause, F = Factor.

  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Descent rate-Capability exceeded - C
  • — Personnel issues-Task performance-Use of equip/info-Aircraft control-Instructor/check pilot
  • — Environmental issues-Conditions/weather/phenomena-Wind-Tailwind-Effect on operation

Verbatim from NTSB's published report. Source file NTSB_2020_CEN20CA326.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

Related research

Matched on aircraft type or causal vocabulary (stall). All research papers