NTSB CAROL · Event
Event SEA91FA143
Aircraft involved
Probable cause & findings
THE CONTROL INTERFERENCE BY THE MECHANIC WHEN HE INADVERTENTLY RAISED THE COLLECTIVE PITCH AND THE COPILOT'S FAILURE TO ATTEND THE FLIGHT CONTROLS. FACTORS RELATING TO THE ACCIDENT WERE THE MOTION SICKNESS OF THE MECHANIC, INADEQUATE COLLECTIVE PITCH CONTROL LOCKING MECHANISM UTILIZED BY THE COMPANY, AND ADMINISTRATIVE TASKS THAT DIVERTED THE CO-PILOT'S ATTENTION FROM ATTENDING THE FLIGHT CONTROLS.
Factual narrative
THE ACFT WAS ON AN EXTERNAL LOAD LOGGING OPN AND THE PIC HAD LANDED AT A FIELD SITE TO REFUEL. THE PIC EXITED, WITH THE ACFT RUNNING AT FULL RPM WHILE IT WAS BEING REFUELED, AND THE COPILOT REMAINED IN THE RIGHT SEAT COMPLETING LOAD REPORTS. THE ACFT CONTROLS WERE UNATTENDED. THE CREW CHIEF WAS SEATED IN THE AFT FACING HOIST OPR STATION, WHICH HAD THE COLLECTIVE PITCH STICK INSTALLED BESIDE THE SEAT. HE HAD BECOME AIR SICK DURING THE FLT, AND REMAINED SEATED AFTER THE PIC EXITED. WHEN HE ATTEMPTED TO EXIT, WHICH REQUIRED THAT HE STAND, TURN AROUND AND STEP UP OUT OF THE SEAT WELL, THE ACFT TOOK OFF TO A HOVER AND ROTATED TO THE LEFT. THE TAIL ROTOR STRUCK A ROTOR BLADE BOX ON TOP OF A SUPPORT TRAILER PARKED BY THE REFUELING SITE, FRACTURING THE AFT TAIL BOOM, PYLON AND TAIL ROTOR FROM THE ACFT. THE ACFT PITCHED NOSE DOWN, ROLLED OVER AND IMPACTED THE GROUND. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1991_SEA91FA143.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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