NTSB CAROL · Event
Event WPR11LA190
Aircraft involved
Probable cause & findings
The pilot did not maintain adequate altitude during takeoff, which resulted in ground contact and a dynamic rollover.
Factual narrative
On April 6, 2011, at 1355 Pacific daylight time, a Bell 47G helicopter, N9FK, sustained substantial damage when it impacted terrain following a loss of control during departure at Zamperini Field (TOA), Torrance, California. The private pilot, the sole occupant, received minor injuries. The owner/pilot was operating the helicopter under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which was originating at the time of the accident. A flight plan had not been filed. The pilot reported that he received clearance to take off. He applied power and pitch, and lifted up approximately 2 to 3 feet while starting a pedal turn to the right. He stated that the helicopter "abruptly started to turn right hard and he had no control over the helicopter." He immediately lowered the collective to stop the rotation. When the helicopter touched down, it immediately rolled onto its right side, shattering the cabin bubble and main rotor blades. Additionally, the fuselage was distorted and bent. An airport operations employee heard the noise and responded to assist the pilot. He said the pilot told him that he “was in a hover just above the ground. I was cleared for takeoff and it just went over.” The wind reported at 1357, at Torrance, was from 270 degrees at 8 knots; no wind gusts were reported during the 24-hour period on the day of the accident. The pilot did not report any known preimpact mechanical discrepancies with the helicopter. The helicopter pilot reported that he applied power and pitch for takeoff and lifted up about 2 to 3 feet while starting a pedal turn to the right. He said that the helicopter then abruptly started to turn hard to the right and that he then had no control over the helicopter, so he immediately lowered the collective to stop the rotation. When the helicopter touched down, it immediately rolled onto its right side, shattering the cabin bubble and the main rotor blades. An airport operations employee heard the noise and responded to assist the pilot. He said that the pilot told him that he was in a hover just above the ground and that he “was cleared for takeoff and it just went over.” No gusts were reported on the day of the accident. The pilot did not report any known preimpact mechanical discrepancies with the helicopter. It is likely that the pilot simultaneously performed a right-pedal turn while transitioning to forward flight at too low an 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).
- C Personnel issues-Action/decision-Action-Incorrect action sequence-Pilot - C
- C Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Altitude-Not attained/maintained - C
Verbatim from NTSB's published report. Source file
NTSB_2011_WPR11LA190.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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