NTSB CAROL · Event
Event CEN12FA579
Aircraft involved
Probable cause & findings
The airplane's entry into a pilot-induced oscillation and the pilot’s loss of airplane control during the takeoff initial climb. Contributing to the accident was the left entrance door opening in flight for undetermined reasons.
Factual narrative
HISTORY OF FLIGHT
On August 28, 2012, about 0949 central daylight time, a Lee SQ-2000 experimental airplane, N416, owned and operated by the pilot, was substantially damaged during takeoff from Pierre Regional Airport (KPIR), Pierre, South Dakota. The certificated private pilot was fatally injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed during the flight. No flight plan was filed. The local flight was originating at the time of the accident. On takeoff leg at about 50 feet above the ground, two witnesses observed the left “gull-wing” entrance door to be open and the airplane enter into a series of four up and down pitch oscillations. During the last pitch down oscillation, the airplane impacted the runway at a steep descent angle.
PERSONNEL INFORMATION
The pilot of N416, age 69, held a private pilot certificate with an airplane single-engine land rating. On October 5, 2011, the pilot was issued a limited third-class medical certificate, with the limitation that corrective lenses be worn while flying. At the time of the medical examination, the pilot reported having 330 hours of flight experience, with 2 hours in the last six months.
AIRCRAFT INFORMATION
The accident airplane was a KLS Composites (Kit), SQ-2000, which the pilot purchased on December 25, 2001. The airplane was issued a special airworthiness certificate on March 18, 2004. During April 2012, the pilot completed the installation of a Continental IO-360C engine. The pilot maintained detailed construction records of the accident airplane, to include construction of the “gull-wing” entrance doors. In these records, the pilot wrote that during flight it was very easy to open the doors and had constructed a door lock “clip” to prevent inadvertent opening of the entrance door closing mechanism. In these records, the pilot also described the aircraft being very pitch sensitive.
METEOROLOGICAL INFORMATION
At 0953, the KPIR automated weather observation system reported the following weather conditions: Wind 090 degrees at 8 knots; sky clear; temperature 27 degrees Celsius (C); dew point 17 degrees C; altimeter setting 29.93 inches of mercury.
WRECKAGE AND IMPACT INFORMATION
Following impact with the runway, the airplane slid to a stop on the edge of the runway and a postimpact fire ensued. The distance from initial runway impact to the main wreckage location was about 500 feet. During examination, the engine crankshaft was rotated and a compression check was confirmed on all cylinders. Propeller impact with the runway resulted in the shredding of over half of the propeller’s diameter. Flight control surfaces were accounted for, although flight control continuity could not be confirmed due to impact and fire damage. Examination of the airframe, engine and propeller did not reveal any anomalies associated with a preimpact failure or malfunction. Both “gull-wing” entrance doors separated from the airplane during the impact sequence and were not fire damaged. Examination of the left entrance “gull-wing” door revealed a witness mark corresponding to the door closing mechanism in a “partially closed” position. Extensive fire damage of the fuselage surrounding the left entrance door prevented further analysis of door failure.
MEDICAL AND PATHOLOGICAL INFORMATION
On August 30, 2012, an autopsy was performed on the pilot at the Rapid City, South Dakota Regional Hospital. The cause of death was attributed to blunt force injuries. The FAA's Civil Aeromedical Institute in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. No carbon monoxide, cyanide, or drugs were detected in the blood, and no ethanol was detected in vitreous. During the airplane’s initial takeoff climb, two ground witnesses observed the left “gull-wing” entrance door to be open. They reported that when the airplane was about 50 feet above the ground, it entered a series of approximately four pitch oscillations. During the last pitch-down oscillation, the airplane impacted the runway at a steep descent angle and then skidded forward about 500 feet, coming to a stop near the right side of the runway. A postimpact fire ensued. Examination of the airframe, engine, propeller and the door did not reveal any anomalies associated with a preimpact failure or malfunction. 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-Task performance-Use of equip/info-Aircraft control-Pilot - C
- C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Pitch control-Incorrect use/operation - C
- F Aircraft-Aircraft structures-Doors-Passenger/crew doors-Unintentional use/operation - F
Verbatim from NTSB's published report. Source file
NTSB_2012_CEN12FA579.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…
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