NTSB CAROL · Event
Event CEN21LA226
Aircraft involved
Probable cause & findings
The flight instructor’s failure to maintain aircraft control resulting in the exceedance of the glider’s critical angle of attack following the breakage of the weak/safety link during a winch launch, which resulted in an aerodynamic stall and spin, and subsequent impact with trees and terrain.
Factual narrative
The flight instructor of the instructional glider flight reported that during a winch launch with the student pilot, the glider accelerated to 70 kts exceeding the winch launch speed. As the flight instructor attempted to decrease the airspeed to the normal winch launch speed, the weak/safety link broke and the glider separated from the towing cable. The flight instructor attempted to maneuver the glider for a landing back to the runway; however, during the turn to enter the final approach, the glider’s critical angle of attack was exceeded, and the glider entered an aerodynamic stall/spin. The glider impacted trees and terrain coming to rest on a grass field. The glider sustained substantial damage to the fuselage and to both wings. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation. The flight instructor also reported that he should have maintained sufficient airspeed to prevent a “stall/spin” at a low altitude. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- — Personnel issues-Task performance-Use of equip/info-Aircraft control-Instructor/check pilot
- — Personnel issues-Task performance-Use of equip/info-Use of equip/system-Pilot
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Angle of attack-Capability exceeded
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained
Verbatim from NTSB's published report. Source file
NTSB_2021_CEN21LA226.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (stall). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- NASA NTRS 2026 · Conference Paper
Computational Analysis of Steady State Aerodynamics of Transonic Truss-Braced Wing Configuration in Deep Stall
This study presents a computational investigation of steady state aerodynamics of the Subsonic Ultra-Green Aircraft Research (SUGAR) Transonic Truss-Braced Wing (TTBW) configuration over a wide range …
- arXiv 2023 · arXiv preprint
Automating Bird Diverter Installation through Multi-Aerial Robots and Signal Temporal Logic Specifications
This paper tackles the task assignment and trajectory generation problem for bird diverter installation using a fleet of multi-rotors.
- arXiv 2023 · arXiv preprint
Variation of Critical Crystallization Pressure for the Formation of Square Ice in Graphene Nanocapillaries
Two-dimensional square ice in graphene nanocapillaries at room temperature is a fascinating phenomenon and has been confirmed experimentally.
- arXiv 2023 · arXiv preprint
Polycrystallinity enhances stress build-up around ice
Damage caused by freezing wet, porous materials is a widespread problem, but is hard to predict or control. Here, we show that polycrystallinity makes a great difference to the stress build-up process…
- arXiv 2022 · arXiv preprint
Enhanced Prediction of Three-dimensional Finite Iced Wing Separated Flow Near Stall
Icing on three-dimensional wings causes severe flow separation near stall. Standard improved delayed detached eddy simulation (IDDES) is unable to correctly predict the separating reattaching flow due…
- Embry-Riddle Scholarly Commons 2021 · Journal article (JAAER)
Analysis on the Negative Emotional, Physiological, and Cognitive Responses Elicited from of the Activation of a Stall Alarm
Failing to identify an aerodynamic stall can lead to the inability of an aircraft to sustain flight. To warn pilots of an impending or fully-developed stall, many aircraft have safety devices installe…
Browse the full corpus — academia portal ↗