NTSB CAROL · Event
Event GAA15CA224
Aircraft involved
Probable cause & findings
The helicopter flight instructor's delayed remedial action during an autorotation resulting in a loss of control and impact with terrain.
Factual narrative
According to the flight instructor, while performing a simulated, right turn, 180 degree autorotation the helicopter impacted the ground and rolled over. The flight instructor stated that at 200 feet AGL, the low rotor RPM horn sounded, and he and the student pilot "attempted a recovery." The flight instructor reported that after hearing the low rotor RPM horn, but prior to impact, "a loud thumping noise could be heard and a violent shake in the cyclic could be felt." He stated that he chose to level the helicopter before it impacted the terrain and rolled. The helicopter sustained substantial damage to the main rotor system, fuselage and tail boom. The pilot reported that there were no mechanical failures or anomalies prior to flight that would have prevented normal operation. According to the flight instructor, while performing a simulated, right turn, 180 degree autorotation the helicopter impacted the ground and rolled over. The flight instructor stated that at 200 feet AGL, the low rotor RPM horn sounded, and he and the student pilot "attempted a recovery." The flight instructor reported that after hearing the low rotor RPM horn, but prior to impact, "a loud thumping noise could be heard and a violent shake in the cyclic could be felt." He stated that he chose to level the helicopter before it impacted the terrain and rolled. The helicopter sustained substantial damage to the main rotor system, fuselage and tail boom. The pilot reported that there were no mechanical failures or anomalies prior to flight that would have prevented normal operation. 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).
- C Personnel issues-Action/decision-Action-Delayed action-Instructor/check pilot - C
- C Personnel issues-Task performance-Use of equip/info-Aircraft control-Instructor/check pilot - C
- C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Prop/rotor parameters-Not attained/maintained - C
Verbatim from NTSB's published report. Source file
NTSB_2015_GAA15CA224.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 (loss of control). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Scoping Review of Aviation Loss of Control Inflight Research
Loss of control – inflight (LOC-I) contributes to aircraft accidents at unacceptably high rates. Significant industry efforts and research have aimed to improve LOC-I prevention, detection, and recove…
- SKYbrary (Eurocontrol) 2024 · SKYbrary article
Loss of Control In-Flight (LOC-I) — SKYbrary Knowledge Base
SKYbrary comprehensive knowledge-base entry on Loss of Control In-Flight — definitions, contributing factors, accident case studies (Air France 447, Colgan 3407), and prevention strategies.
- NTSB Aircraft Accident Reports 2022 · Accident report
Loss of Control on Takeoff in Icing Conditions — Citation 560XL
Cessna Citation 560XL fatal takeoff icing accident, March 2018. Investigation of a Citation 560XL loss-of-control takeoff accident in icing conditions.
- Semantic Scholar 2021 · Article (Aviation)
ANALYSIS OF GENERAL AVIATION FIXED-WING AIRCRAFT ACCIDENTS INVOLVING INFLIGHT LOSS OF CONTROL USING A STATE-BASED APPROACH
Inflight loss of control (LOC-I) is a significant cause of General Aviation (GA) fixed-wing aircraft accidents. The United States National Transportation Safety Board’s database provides a rich source…
- NASA NTRS 2021 · Presentation
Use of Design of Experiments in Determining Neural Network Architectures for Loss of Control Detection
Abstract—We describe empirical methods for selecting a neural network architecture to implement belief state inference on generic commercial transport aircraft.
- NASA NTRS 2021 · Conference Paper
Use of Design of Experiments in Determining Neural Network Architectures for Loss of Control Detection
We describe empirical methods for selecting a neural network architecture to implement belief state inference on generic commercial transport aircraft.
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